Lifespan Development

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Lifespan Development

Santrock, J. W. (2019). Life-span development (17th ed.). New York, NY: McGraw-Hill Education.

Week 4 Assignment: The Adolescent Brain – Workshop Handout

Required Resources
Read/review the following resources for this activity:

Textbook: Chapter 11
Minimum of 2 scholarly sources (in addition to course text)

Your textbook details a sequence in which the human brain develops. The limbic system, or the seat of emotions and experience of rewards, (p. 344) is said to be completely developed in early adolescence. However, the pre-frontal cortex, also called the, judgement region doesn’t finish developing until at least a person is nearly an adult.
We could reasonably suggest that during the adolescent stage, it may be biologically difficult for a person to wrangle their emotions, impulses, and behaviors.
As a medical educator, how would you teach a group of parents about why their adolescent boys and girls are “acting out”?
In approximately 3 pages, create a “fact sheet” in MS Word that includes a chart, images, or banners, tables, etc., that explain why adolescent children may be less logical and more emotional in their decision-making. As part of your fact sheet, include ideas on how parents can best support their teenager during this time
Be sure that you use peer-reviewed research and the textbook to support your 3-page handout.
Writing Requirements (APA format)

Length: 2.5-3 pages (not including title page or references page)
Includes engaging presentation elements (i.e. images, banners, tables)
Attributes proper credit to outside sources (due to the creative nature of this assignment, attribution may look different than it does in a standard essay – that is ok so long as you credit your source in such a way that your audience can easy track down the sources you reference)

This activity will be graded using the Essay Grading Rubric. Please review the following link:
Link (webpage):
Course Outcomes (CO): 1, 3, 4, 5
Due Date: By 11:59 p.m. MT on Sunday
PSYC290 Week 4 Assignment

PSYC290 Week 4 Assignment


This criterion is linked to a Learning OutcomeAssignment Content

60.0 pts
Addresses all aspects of the questions, applying professional knowledge, and research regarding weekly concepts.
51.0 pts
Addresses most aspects of the questions, applying professional knowledge, , and research regarding weekly concepts.
45.0 pts
Addresses some aspects of the questions, applying professional knowledge, and research regarding weekly concepts.
36.0 pts
Minimally addresses the questions, applying professional knowledge, and research regarding weekly concepts.
0.0 pts
No effort

60.0 pts

This criterion is linked to a Learning OutcomeResearch

20.0 pts
Research is supportive of the rationale presented. Sources are distinctive. Addresses all of the issues stated in the assignment criteria. Assignment meets all source requirements, and citations and references are properly formatted in APA style throughout
17.0 pts
Research is timely and relevant, and addresses all of the issues stated in the assignment criteria. Assignment meets all source requirements, and citations and references are mostly properly formatted in APA style throughout.
15.0 pts
Research is adequate. Sources are standard in relevance, quality of outside sources, and/or timeliness. Assignment meets all source requirements, and citations and references are somewhat properly formatted in APA style throughout.
12.0 pts
An inadequate number of outside sources were used to support the assignment. Limited research is apparent. Assignment fails to meet source requirements and/or citations and references are improperly formatted in APA style throughout.
0.0 pts
No effort

20.0 pts

This criterion is linked to a Learning OutcomeProfessional Communication

20.0 pts
Presents information using clear and concise language in an organized, professional manner. The work is well presented and includes all required elements. The overall appearance is neat and professional.
17.0 pts
Presents information in an organized manner, although a few mechanical errors may be present. The overall appearance is generally neat, with a few minor flaws or missing elements.
15.0 pts
Presents information using understandable language but is somewhat disorganized and/or some mechanical errors may be present. The overall appearance is general, and some elements are missing.
12.0 pts
Presents information that is not clear, logical, professional or organized to the point that the reader has difficulty understanding the message and/or numerous mechanical errors are present. The work is not neat and many required elements are missing or flawed.
0.0 pts
No effort

20.0 pts

Total Points: 100.0

chapter 11
chapter outline
1 The Nature of Adolescence
Learning Goal 1 Discuss the nature of adolescence.
2 Physical Changes
Learning Goal 2 Describe the changes involved in puberty, as well as changes in the brain and sexuality during adolescence.
The Brain
Adolescent Sexuality
3 Issues in Adolescent Health
Learning Goal 3 Identify adolescent problems related to health, substance use and abuse, and eating disorders.
Adolescent Health
Substance Use and Abuse
Eating Disorders
4 Adolescent Cognition
Learning Goal 4 Explain cognitive changes in adolescence.
Piaget’s Theory
Adolescent Egocentrism
Information Processing
5 Schools
Learning Goal 5 Summarize some key aspects of how schools influence adolescent development.
The Transition to Middle or Junior High School
Effective Schools for Young Adolescents
High School
Extracurricular Activities
Service Learning
©Image Source/Getty Images
Fifteen-year-old Latisha developed Page 338a drinking problem, and she was kicked off the cheerleading squad for missing too many practice sessions—but that didn’t make her stop drinking. She and her friends began skipping school regularly so they could drink.
Fourteen-year-old Arnie is a juvenile delinquent. Last week he stole a TV set, struck his mother and bloodied her face, broke some streetlights in the neighborhood, and threatened a boy with a wrench and hammer.
Twelve-year-old Katie, more than just about anything else, wanted a playground in her town. She knew that the other kids also wanted one, so she put together a group that generated funding ideas for the playground. They presented their ideas to the town council. Her group attracted more youth, and they raised money by selling candy and sandwiches door-to-door. The playground became a reality, a place where, as Katie says, “People have picnics and make friends.” Katie’s advice: “You won’t get anywhere if you don’t try.”
Adolescents like Latisha and Arnie are the ones we hear about the most. But there are many adolescents like Katie who contribute in positive ways to their communities and competently make the transition through adolescence. Indeed, for most young people, adolescence is not a time of rebellion, crisis, pathology, and deviance. A far more accurate vision of adolescence is that it is a time of evaluation, decision making, commitment, and carving out a place in the world. Most of the problems of today’s youth are not with the youth themselves, but with needs that go unmet. To reach their full potential, adolescents need a range of legitimate opportunities as well as long-term support from adults who care deeply about them (Miller & Cho, 2018; Ogden & Haden, 2019).
Katie Bell (front) and some of her volunteers.
©Ronald Cortes
topical connections looking back
In middle and late childhood, physical growth continues but at a slower pace than in infancy and early childhood. Gross motor skills become much smoother and more coordinated, and fine motor skills also improve. Significant advances in the development of the prefrontal cortex occur. Cognitive and language skills also improve considerably. In terms of cognitive development, most children become concrete operational thinkers, long-term memory increases, and metacognitive skills improve, especially if children learn a rich repertoire of strategies. In terms of language development, children’s understanding of grammar and syntax increases, and learning to read becomes an important achievement.
Adolescence is a transitional period in the human life span, linking childhood and adulthood Page 339. We begin the chapter by examining some general characteristics of adolescence and then explore the major physical changes and health issues of adolescence. Next, we consider the significant cognitive changes that characterize adolescence and conclude the chapter by describing various aspects of schools for adolescents.
1 The Nature of Adolescence
LG1 Discuss the nature of adolescence.
As in development during childhood, genetic/biological and environmental/social factors influence adolescent development. During their childhood years, adolescents experienced thousands of hours of interactions with parents, peers, and teachers, but now they face dramatic biological changes, new experiences, and new developmental tasks. Relationships with parents take a different form, moments with peers become more intimate, and dating occurs for the first time, as do sexual exploration and possibly intercourse. The adolescent’s thoughts become more abstract and idealistic. Biological changes trigger a heightened interest in body image. Adolescence has both continuity and discontinuity with childhood.
There is a long history of worrying about how adolescents will “turn out.” In 1904, G. Stanley Hall proposed the “storm-and-stress” view that adolescence is a turbulent time charged with conflict and mood swings. However, when Daniel Offer and his colleagues (1988) studied the self-images of adolescents in the United States, Australia, Bangladesh, Hungary, Israel, Italy, Japan, Taiwan, Turkey, and West Germany, at least 73 percent of the adolescents displayed a healthy self-image. Although there were differences among them, the adolescents were happy most of the time, they enjoyed life, they perceived themselves as able to exercise self-control, they valued work and school, they felt confident about their sexual selves, they expressed positive feelings toward their families, and they felt they had the capability to cope with life’s stresses—not exactly a storm-and-stress portrayal of adolescence.
Public attitudes about adolescence emerge from a combination of personal experience and media portrayals, neither of which produces an objective picture of how normal adolescents develop (Feldman & Elliott, 1990). Some of the readiness to assume the worst about adolescents likely involves the short memories of adults. Many adults measure their current perceptions of adolescents by their memories of their own adolescence. Adults may portray today’s adolescents as more troubled, less respectful, more self-centered, more assertive, and more adventurous than they were.

Growing up has never been easy. However, adolescence is not best viewed as a time of rebellion, crisis, pathology, and deviance. A far more accurate vision of adolescence describes it as a time of evaluation, of decision making, of commitment, and of carving out a place in the world. Most of the problems of today’s youth are not with the youth themselves. What adolescents need is access to a range of legitimate opportunities and to long-term support from adults who care deeply about them. What might be some examples of such support and caring?
©Regine Mahaux/The Image Bank/Getty Images
However, in matters of taste and manners, the young people Page 340of every generation have seemed unnervingly radical and different from adults—different in how they look, in how they behave, in the music they enjoy, in their hairstyles, and in the clothing they choose. It would be an enormous error, though, to confuse adolescents’ enthusiasm for trying on new identities and enjoying moderate amounts of outrageous behavior with hostility toward parental and societal standards. Acting out and boundary testing are time-honored ways in which adolescents move toward accepting, rather than rejecting, parental values.
Negative stereotyping of adolescence has been extensive (Jiang & others, 2018; Petersen & others, 2017). However, much of the negative stereotyping has been fueled by media reports of a visible minority of adolescents. In the last decade there has been a call for adults to have a more positive attitude toward youth and emphasize their positive development. Indeed, researchers have found that a majority of adolescents are making the transition from childhood through adolescence to adulthood in a positive way (Seider, Jayawickreme, & Lerner, 2017). For example, a recent study of non-Latino White and African American 12- to 20-year-olds in the United States found that they were characterized much more by positive than problematic development, even in their most vulnerable times (Gutman & others, 2017). Their engagement in healthy behaviors, supportive relationships with parents and friends, and positive self-perceptions were much stronger than their angry and depressed feelings.
©RubberBall Productions/Getty Images
Although most adolescents negotiate the lengthy path to adult maturity successfully, too large a group does not. Ethnic, cultural, gender, socioeconomic, age, and lifestyle differences influence the actual life trajectory of each adolescent (Green & others, 2018; Hadley, 2018; Kimmel & Aronson, 2018; McQueen, 2017; Ruck, Peterson-Badali, & Freeman, 2017). Different portrayals of adolescence emerge, depending on the particular group of adolescents being described. Today’s adolescents are exposed to a complex menu of lifestyle options through the media, and many face the temptations of drug use and sexual activity at increasingly young ages (Johnston & others, 2018). Too many adolescents are not provided with adequate opportunities and support to become competent adults (Bill & Melinda Gates Foundation, 2018; Edalati & Nicholls, 2018; Lo & others, 2017; Loria & Caughy, 2018; Miller & Cho, 2018; Umana-Taylor & Douglass, 2017).
Recall that social policy is the course of action designed by the national government to influence the welfare of its citizens. Currently, many researchers in adolescent development are designing studies that they hope will lead to wise and effective social policy decision making (Duncan, Magnuson, & Votruba-Drzal, 2017; Galinsky & others, 2017; Hall, 2017).
Research indicates that youth benefit enormously when they have caring adults in their lives in addition to parents or guardians (Frydenberg, 2019; Masten, 2017; Masten & Kalstabakken, 2018; Ogden & Hagen, 2019; Pomerantz & Grolnick, 2017). Caring adults—such as coaches, neighbors, teachers, mentors, and after-school leaders—can serve as role models, confidants, advocates, and resources. Relationships with caring adults are powerful when youth know they are respected, that they matter to the adult, and that the adult wants to be a resource in their lives. However, in a survey, only 20 percent of U.S. 15-year-olds reported having meaningful relationships with adults outside their family who were helping them to succeed in life (Search Institute, 2010).
Review Connect Reflect
LG1 Discuss the nature of adolescence.

What characterizes adolescent development? What especially needs to be done to improve the lives of adolescents?


In this section you read about how important it is for adolescents to have caring adults in their lives. In previous chapters, what did you learn about the role parents play in their children’s lives leading up to adolescence that might influence adolescents’ development?

Reflect Your Own Personal Journey of Life

Was your adolescence better described as a stormy and stressful time or as one of trying out new identities as you sought to find an identity of your own? Explain.

Page 341
2 Physical Changes
LG2 Describe the changes involved in puberty, as well as changes in the brain and sexuality during adolescence.
The Brain
Adolescent Sexuality
One father remarked that the problem with his teenage son was not that he grew, but that he did not know when to stop growing. As we will see, there is considerable variation in the timing of the adolescent growth spurt. In addition to pubertal changes, other physical changes we will explore involve sexuality and the brain.
Puberty is not the same as adolescence. For most of us, puberty ends long before adolescence does, although puberty is the most important marker of the beginning of adolescence.
Puberty is a brain-neuroendocrine process occurring primarily in early adolescence that provides stimulation for the rapid physical changes that take place during this period of development (Berenbaum, Beltz, & Corley, 2015; Shalitin & Kiess, 2017; Susman & Dorn, 2013). Puberty is not a single, sudden event. We know whether a young boy or girl is going through puberty, but pinpointing puberty’s beginning and end is difficult. Among the most noticeable changes are signs of sexual maturation and increases in height and weight.
Sexual Maturation, Height, and Weight Think back to the onset of your puberty. Of the striking changes that were taking place in your body, what was the first to occur? Researchers have found that male pubertal characteristics typically develop in this order: increase in penis and testicle size, appearance of straight pubic hair, minor voice change, first ejaculation (which usually occurs through masturbation or a wet dream), appearance of kinky pubic hair, onset of maximum growth in height and weight, growth of hair in armpits, more detectable voice changes, and, finally, growth of facial hair.
What is the order of appearance of physical changes in females? First, either the breasts enlarge or pubic hair appears. Later, hair appears in the armpits. As these changes occur, the female grows in height and her hips become wider than her shoulders. Menarche—a girl’s first menstruation—comes rather late in the pubertal cycle. Initially, her menstrual cycles may be highly irregular. For the first several years, she may not ovulate every menstrual cycle; some girls do not ovulate at all until a year or two after menstruation begins. No voice changes comparable to those in pubertal males occur in pubertal females. By the end of puberty, the female’s breasts have become more fully rounded.
Marked weight gains coincide with the onset of puberty. During early adolescence, girls tend to outweigh boys, but by about age 14 boys begin to surpass girls. Similarly, at the beginning of the adolescent period, girls tend to be as tall as or taller than boys of their age, but by the end of the middle school years most boys have caught up or, in many cases, surpassed girls in height.
As indicated in Figure 1, the growth spurt occurs approximately two years earlier for girls than for boys. The mean age at the beginning of the growth spurt in girls is 9; for boys, it is 11. The peak rate of pubertal change occurs at 11½ years for girls and 13½ years for boys. During their growth spurt, girls increase in height about 3½ inches per year, boys about 4 inches. Boys and girls who are shorter or taller than their peers before adolescence are likely to remain so during adolescence; however, as much as 30 percent of an individual’s height in late adolescence is unexplained by his or her height in the elementary school years.
FIGURE 1 PUBERTAL GROWTH SPURT. On average, the peak of the growth spurt during puberty occurs two years earlier for girls (11½) than for boys (13½). How are hormones related to the growth spurt and to the difference between the average height of adolescent boys and that of girls?
Is age of pubertal onset linked to how tall boys and girls will be toward the end of adolescence? One study found that for girls, earlier onset of menarche, breast development, and growth spurt were linked to shorter height at 18 years of age; however, for boys, earlier age of growth spurt and slower progression through puberty were associated with being taller at 18 years of age (Yousefi & others, 2013).
Hormonal Changes Behind the first whisker in boys and the widening of hips in girls is a flood of hormones, powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream.
The concentrations of certain hormones Page 342increase dramatically during adolescence (Berenbaum, Beltz, & Corley, 2015; Herting & Sowell, 2017; Nguyen, 2018; Piekarski & others, 2017). Testosterone is a hormone associated in boys with genital development, increased height, and deepening of the voice. Estradiol is a type of estrogen that in girls is associated with breast, uterine, and skeletal development. In one study, testosterone levels increased eighteenfold in boys but only twofold in girls during puberty; estradiol increased eightfold in girls but only twofold in boys (Nottelmann & others, 1987). Thus, both testosterone and estradiol are present in the hormonal makeup of both boys and girls, but testosterone dominates in male pubertal development, estradiol in female pubertal development (Benyi & Savendahl, 2017). A study of 9- to 17-year-old boys found that testosterone levels peaked at 17 years of age (Khairullah & others, 2014).
The same influx of hormones that grows hair on a male’s chest and increases the fatty tissue in a female’s breasts may also contribute to psychological development in adolescence (Berenbaum, Beltz, & Corley, 2015; Wang & others, 2017). In one study of boys and girls ranging in age from 9 to 14, a higher concentration of testosterone was present in boys who rated themselves as more socially competent (Nottelmann & others, 1987). However, a research review concluded that there is insufficient quality research to confirm that changing testosterone levels during puberty are linked to mood and behavior in adolescent males (Duke, Balzer, & Steinbeck, 2014). And hormonal effects by themselves do not account for adolescent development (Susman & Dorn, 2013). For example, in one study, social factors were much better predictors of young adolescent girls’ depression and anger than hormonal factors (Brooks-Gunn & Warren, 1989). Behavior and moods also can affect hormones (DeRose & Brooks-Gunn, 2008). Stress, eating patterns, exercise, sexual activity, tension, and depression can activate or suppress various aspects of the hormonal system (Marceau, Dorn, & Susman, 2012). In sum, the hormone-behavior link is complex (Susman & Dorn, 2013).
Timing and Variations in Puberty In the United States—where children mature up to a year earlier than children in European countries—the average age of menarche has declined significantly since the mid-nineteenth century (see Figure 2). Also, recent studies in Korea and Japan (Cole & Mori, 2018), China (Song & others, 2017), and Saudi Arabia (Al Alwan & others, 2017) found that pubertal onset has been occurring earlier in recent years. Fortunately, however, we are unlikely to see pubescent toddlers, since what has happened in the past century is likely the result of improved nutrition and health.
FIGURE 2 AGE AT MENARCHE IN NORTHERN EUROPEAN COUNTRIES AND THE UNITED STATES IN THE NINETEENTH AND TWENTIETH CENTURIES. Notice the steep decline in the age at which girls experienced menarche in four northern European countries and the United States from 1845 to 1969. Recently the age at which girls experience menarche has been leveling off.
Why do the changes of puberty occur when they do, and how can variations in their timing be explained? The basic genetic program for puberty is wired into the species (Day & others, 2017; Kiess & others, 2016). Weight also is linked to pubertal onset. A cross-cultural study in 29 countries found that childhood obesity was linked to early puberty in girls (Currie & others, 2012). And a study of Chinese girls confirmed that childhood obesity contributed to an earlier onset of puberty (Zhai & others, 2015).
Experiences that are linked to earlier pubertal onset include nutrition, an urban environment, low socioeconomic status, adoption, father absence, family conflict, maternal harshness, child maltreatment, and early substance use (Bratke & others, 2017). For example, a recent study found that child sexual abuse was linked to earlier pubertal onset (Noll & others, 2017). In many cases, puberty comes months earlier in these situations, and this earlier onset of puberty is likely explained by high rates of conflict and stress in these social contexts.
What are some of the differences in the ways girls and boys experience pubertal growth?
©Fuse/Getty Images
For most boys, the pubertal sequence may begin as early as age 10 or as late as 13½, and it may end as early as age 13 or as late as 17. Thus, the normal range is wide enough that, given two boys of the same chronological age, one might complete the pubertal sequence before the other one has begun it. For girls, menarche is considered within the normal range if it appears between the ages of 9 and 15. An increasing number of U.S. girls are beginning puberty at 8 and 9 years of age, with African American girls developing earlier than non-Latino White girls (Herman-Giddens, 2007; Selkie, 2018; Sorensen & others, 2012).
Body Image One psychological aspect of physical Page 343change in puberty is universal: Adolescents are preoccupied with their bodies and develop images of what their bodies are like (Senin-Calderon & others, 2017; Solomon-Krakus & others, 2017). Preoccupation with body image is strong throughout adolescence but is especially acute during early adolescence, a time when adolescents are more dissatisfied with their bodies than in late adolescence.
The recent dramatic increase in Internet and social media use has raised concerns about their influence on adolescents’ body images. For example, a recent study of U.S. 12- to 14-year-olds found that heavier social media use was associated with body dissatisfaction (Burnette, Kwitowski, & Mazzeo, 2017). Also, in a recent study of U.S. college women, spending more time on Facebook was related to more frequent body and weight concern comparisons with other women, more attention to the physical appearance of others, and more negative feelings about their own bodies (Eckler, Kalyango, & Paasch, 2017), In sum, various aspects of exposure to the Internet and social media are increasing the body dissatisfaction of adolescents and emerging adults, especially females.
Gender differences characterize adolescents’ perceptions of their bodies (Hoffman & Warschburger, 2017; Mitchison & others, 2017). In general, girls are less happy with their bodies and have more negative body images than boys throughout puberty (Griffiths & others, 2017). In a recent U.S. study of young adolescents, boys had a more positive body image than girls (Morin & others, 2017). Girls’ more negative body images may be due to media portrayals of the attractiveness of being thin and the increase in body fat in girls during puberty (Benowitz-Fredericks & others, 2012). One study found that both boys’ and girls’ body images became more positive as they moved from the beginning to the end of adolescence (Holsen, Carlson Jones, & Skogbrott Birkeland, 2012).
Early and Late Maturation You may have entered puberty earlier or later than average, or perhaps you were right on schedule. Adolescents who mature earlier or later than their peers perceive themselves differently (Lee & others, 2017; Wang & others, 2018). In the Berkeley Longitudinal Study some years ago, early-maturing boys perceived themselves more positively and had more successful peer relations than did their late-maturing counterparts (Jones, 1965). When the late-maturing boys were in their thirties, however, they had developed a stronger sense of identity than the early-maturing boys had (Peskin, 1967). This identity development may have occurred because the late-maturing boys had more time to explore life’s options, or because the early-maturing boys continued to focus on their advantageous physical status instead of on career development and achievement. More recent research confirms, though, that at least during adolescence it is advantageous to be an early-maturing rather than a late-maturing boy (Graber, Brooks-Gunn, & Warren, 2006).
Early and late maturation have been linked with body image. In one study, in the sixth grade, early-maturing girls showed greater satisfaction with their figures than did late-maturing girls, but by the tenth grade late-maturing girls were more satisfied (Simmons & Blyth, 1987) (see Figure 3). A possible reason for this is that in late adolescence early-maturing girls are shorter and stockier, whereas late-maturing girls are taller and thinner. Thus, late-maturing girls in late adolescence have bodies that more closely approximate the current American ideal of feminine beauty—tall and thin. Also, one study found that in the early high school years, late-maturing boys had a more negative body image than early-maturing boys (de Guzman & Nishina, 2014).
FIGURE 3 EARLY- AND LATE-MATURING ADOLESCENT GIRLS’ PERCEPTIONS OF BODY IMAGE IN EARLY AND LATE ADOLESCENCE. The sixth-grade girls in this study had positive body image scores if they were early maturers but negative body image scores if they were late maturers (Simmons & Blyth, 1987). Positive body image scores indicated satisfaction with their figures. By the tenth grade, however, it was the late maturers who had positive body image scores.
An increasing number of researchers have found that early maturation increases girls’ vulnerability to a number of problems (Selkie, 2018). Early-maturing girls are more likely to smoke, drink, be depressed, have an eating disorder, engage in delinquency, struggle for earlier independence from their parents, and have older friends; and their bodies are likely to elicit responses from males that lead to earlier dating and earlier sexual experiences (Ibitoye & others, 2017; Pomerantz & others, 2017; Wang & others, 2018). In a recent study, onset of menarche before 11 years of age was linked to a higher incidence of distress disorders, fear disorders, and externalizing disorders in females (Platt & others, 2017). Another study found that early maturation predicted a stable higher level of depression for adolescent girls (Rudolph & others, 2014). Further, researchers recently found that early-maturing girls had higher rates of depression and antisocial behavior as middle-aged adults, mainly because their difficulties began in adolescence and did not lessen over time (Mendle & others, 2018). Further, early-maturing girls tend to have sexual intercourse earlier and to have more unstable sexual relationships, and they are more at risk for physical and verbal abuse in dating (Chen, Rothman, & Jaffee, 2017; Moore, Harden, & Mendle, 2014). And early-maturing girls are less likely to graduate from high Page 344school and tend to cohabit and marry earlier (Cavanagh, 2009). Apparently as a result of their social and cognitive immaturity, combined with early physical development, early-maturing girls are easily lured into problem behaviors, not recognizing the possible long-term negative effects on their development.
In sum, early maturation often has more favorable outcomes in adolescence for boys, especially in early adolescence. However, late maturation may be more favorable for boys, especially in terms of identity and career development. Research increasingly has found that early-maturing girls are vulnerable to a number of problems.
Along with the rest of the body, the brain changes during adolescence, but the study of adolescent brain development is still in its infancy. As advances in technology take place, significant strides are also likely to be made in charting developmental changes in the adolescent brain (Cohen & Casey, 2017; Crone, Peters, & Steinbeis, 2018; Sherman, Steinberg, & Chein, 2018; Steinberg & others, 2018; Vijayakumar & others, 2018). What do we know now?
The dogma of the unchanging brain has been discarded, and researchers are mainly focused on context-induced plasticity of the brain over time (Romeo, 2017; Steinberg, 2017; Zelazo, 2013). The development of the brain mainly changes in a bottom-up, top-down sequence with sensory, appetitive (eating, drinking), sexual, sensation-seeking, and risk-taking brain linkages maturing first and higher-level brain linkages such as self-control, planning, and reasoning maturing later (Zelazo, 2013).
Using fMRI brain scans, scientists have recently discovered that adolescents’ brains undergo significant structural changes (Aoki, Romeo, & Smith, 2017; Crone, Peters, & Steinbeis, 2018; Goddings & Mills, 2017; Rudolph & others, 2017). The corpus callosum, where fibers connect the brain’s left and right hemispheres, thickens in adolescence, and this improves adolescents’ ability to process information (Chavarria & others, 2014). We have described advances in the development of the prefrontal cortex—the highest level of the frontal lobes involved in reasoning, decision making, and self-control. However, the prefrontal cortex doesn’t finish maturing until the emerging adult years, approximately 18 to 25 years of age, or later (Cohen & Casey, 2017; Juraska & Willing, 2017; Sousa & others, 2018).
developmental connection
Brain Development
Although the prefrontal cortex shows considerable development in childhood, it is still not fully mature even in adolescence. Connect to “Physical and Cognitive Development in Middle and Late Childhood.”
At a lower, subcortical level, the limbic system, which is the seat of emotions and where rewards are experienced, matures much earlier than the prefrontal cortex and is almost completely developed in early adolescence (Mueller & others, 2017). The limbic system structure that is especially involved in emotion is the amygdala. Figure 4 shows the locations of the corpus callosum, prefrontal cortex, and the limbic system.
With the onset of puberty, the levels of neurotransmitters change (Cohen & Casey, 2017). For example, an increase in the neurotransmitter dopamine occurs in both the prefrontal cortex and the limbic system during adolescence (Cohen & Casey, 2017). Increases in dopamine have been linked to increased risk taking and the use of addictive drugs (Webber & others, 2017). Researchers also have found that dopamine plays an important role in reward seeking during adolescence (Dubol & others, 2018).
Earlier we described the increased focal activation that is linked to synaptic pruning in a specific region, such as the prefrontal cortex. In middle and late childhood, while there is increased focal activation within a specific brain region such as the prefrontal cortex, there are limited connections across distant brain regions. As adolescents develop, they have more connections across brain areas (Lebel & Deoni, 2018; Quinlin & others, 2017; Sousa & others, 2018; Tashjian, Goldenberg, & Galvan, 2017). The increased connectedness (referred to as brain networks) is especially prevalent across more distant brain regions. Thus, as children develop, greater efficiency and focal activation occurs in close Page 345-by areas of the brain, and simultaneously there is an increase in brain networks connecting more distant brain regions. In a recent study, reduced connectivity between the brain’s frontal lobes and amygdala during adolescence was linked to increased depression (Scheuer & others, 2017).
Many of the changes in the adolescent brain that have been described here involve the rapidly emerging fields of developmental cognitive neuroscience and developmental social neuroscience, in which connections between development, the brain, and cognitive or socioemotional processes are studied (Lauharatanahirun & others, 2018; Mueller & others, 2017; Romer, Reyna, & Sattherthwaite, 2017; Sherman, Steinberg, & Chein, 2018; Steinberg & others, 2018). For example, consider leading researcher Charles Nelson’s (2003) view that, although adolescents are capable of very strong emotions, their prefrontal cortex hasn’t adequately developed to the point at which they can control these passions. It is as if their brain doesn’t have the brakes to slow down their emotions. Or consider this interpretation of the development of emotion and cognition in adolescents: “early activation of strong ‘turbo-charged’ feelings with a relatively unskilled set of ‘driving skills’ or cognitive abilities to modulate strong emotions and motivations” (Dahl, 2004, p. 18).
Of course, a major question is which comes first, biological changes in the brain or experiences that stimulate these changes (Lerner, Boyd, & Du, 2008; Steinberg, 2017). In a longitudinal study, 11- to 18-year-olds who lived in poverty conditions had diminished brain functioning at 25 years of age (Brody & others, 2017). However, the adolescents from poverty backgrounds whose families participated in a supportive parenting intervention did not show this diminished brain functioning in adulthood. Another study found that the prefrontal cortex thickened and more brain connections formed when adolescents resisted peer pressure (Paus & others, 2007). Scientists have yet to determine whether the brain changes come first or whether they result from experiences with peers, parents, and others (Lauharatanahirun & others, 2018; Webber & others, 2017). Once again, we encounter the nature-nurture issue that is so prominent in an examination of development through the life span. Nonetheless, there is adequate evidence that environmental experiences make important contributions to the brain’s development (Cohen & Casey, 2017; Crone, 2017; Sherman, Steinberg, & Chein, 2018).
In closing this section on the development of the brain in adolescence, a further caution is in order. Much of the research on neuroscience and the development of the brain in adolescence is correlational in nature, and thus causal statements need to be scrutinized (Steinberg & others, 2018). This caution, of course, applies to any period in the human life span.
Not only is adolescence characterized by substantial changes in physical growth and the development of the brain, but adolescence also is a bridge between the asexual child and the sexual adult (Diamond & Alley, 2018; Savin-Williams, 2017, 2018). Adolescence is a time of sexual exploration and experimentation, of sexual fantasies and realities, of incorporating sexuality into one’s identity. Adolescents have an almost insatiable curiosity about sexuality. They are concerned about whether they are sexually attractive, how to do sex, and what the future holds for their sexual lives. Although most adolescents experience times of vulnerability and confusion, the majority will eventually develop a mature sexual identity.
In the United States, the sexual culture is widely available to adolescents. In addition to any advice adolescents get from parents, they learn a great deal about sex from television, videos, magazines, the lyrics of popular music, and the Internet (Bleakley & others, 2017; Kinsler & others, 2018; van Oosten & Vandenbosch, 2017). In some schools, sexting is common, as indicated in a recent study of 656 high school students at one school in which 15.8 percent of males and 13.6 percent of females reported sending and 40.5 percent of males and 30.6 percent of females reported receiving explicit sexual pictures on cell phones (Strassberg, Cann, & Velarde, 2017). And in another recent study of 13- to 21-year-old Latinos, engaging in sexting was linked to engaging in penetrative sex (oral, vaginal, and anal sex) (Romo & others, 2017).
Sexual arousal emerges as a new phenomenon in adolescence and it is important to view sexuality as a normal aspect of adolescent development.
—Shirley Feldman
Contemporary Psychologist, Stanford University
Developing a Sexual Identity Mastering emerging sexual feelings and forming a sense of sexual identity are multifaceted and lengthy processes (Diamond & Alley, 2018; Savin-Williams, 2017, 2018). They involve learning to manage sexual feelings (such as sexual arousal and attraction), developing new forms of intimacy, and learning how to regulate sexual behavior to avoid undesirable consequences.
An adolescent’s sexual identity involves activities Page 346, interests, styles of behavior, and an indication of sexual orientation (whether an individual has same-sex or other-sex attractions, or both) (Goldberg & Halpern, 2017). For example, some adolescents have a high anxiety level about sex, others a low level. Some adolescents are strongly aroused sexually, others less so. Some adolescents are very active sexually, others not at all (Hyde & DeLamater, 2017). Some adolescents are sexually inactive in response to their strong religious upbringing; others go to church regularly and yet their religious training does not inhibit their sexual activity.
It is commonly thought that most gays and lesbians quietly struggle with same-sex attractions in childhood, do not engage in heterosexual dating, and gradually recognize that they are a gay or lesbian in mid- to late adolescence. Many youth do follow this developmental pathway, but others do not (Diamond & Alley, 2018; Savin-Williams, 2017, 2018). For example, many youth have no recollection of early same-sex attractions and experience a more abrupt sense of their same-sex attraction in late adolescence. The majority of adolescents with same-sex attractions also experience some degree of other-sex attractions (Carroll, 2018). Even though some adolescents who are attracted to individuals of their same sex fall in love with these individuals, others claim that their same-sex attractions are purely physical (Diamond & Alley, 2018; Savin-Williams, 2017, 2018).
Further, the majority of sexual minority (gay, lesbian, and bisexual) adolescents have competent and successful paths of development through adolescence and become healthy and productive adults. However, in a recent large-scale study, sexual minority adolescents did engage in a higher prevalence of health-risk behaviors (greater drug use and sexual risk taking, for example) compared with heterosexual adolescents (Kann & others, 2016b).
The Timing of Adolescent Sexual Behaviors What is the current profile of sexual activity of adolescents? In a U.S. national survey conducted in 2015, 58 percent of twelfth-graders reported having experienced sexual intercourse, compared with 24 percent of ninth-graders (Kann & others, 2016a). By age 20, 77 percent of U.S. youth report having engaged in sexual intercourse (Dworkin & Santelli, 2007). Nationally, 46 percent of twelfth-graders, 33.5 percent of eleventh-graders, 25.5 percent of tenth-graders, and 16 percent of ninth-graders recently reported that they were currently sexually active (Kann & others, 2016a).
developmental connection
What characterizes the sexual activity of emerging adults (18 to 25 years of age)? Connect to “Physical and Cognitive Development in Early Adulthood.”
What trends in adolescent sexual activity have occurred in recent decades? From 1991 to 2015, fewer adolescents reported any of the following: ever having had sexual intercourse, currently being sexually active, having had sexual intercourse before the age of 13, and having had sexual intercourse with four or more persons during their lifetime (Kann & others, 2016a) (see Figure 5).
Sexual initiation varies by ethnic group in the United States (Kann & others, 2016a). African Americans are likely to engage in sexual behaviors earlier than other ethnic groups, whereas Asian Americans are likely to engage in them later (Feldman, Turner, & Araujo, 1999). In a more recent national U.S. survey of ninth- to twelfth-graders, 48.5 percent of African Americans, 42.5 percent of Latinos, and 39.9 percent of non-Latino Whites said they had experienced sexual intercourse (Kann & others, 2016a). In this study, 8 percent of African Americans (compared with 5 percent of Latinos and 2.5 percent of non-Latino Whites) said they had their first sexual experience before 13 years of age.
Research indicates that oral sex is now a common occurrence among U.S. adolescents (Fava & Bay-Cheng, 2012; Song & Halpern-Felsher, 2010). In a national survey, 51 percent of U.S. 15- to 19-year-old boys and 47 percent of girls in the same age range said they had engaged in oral sex (Child Trends, 2015). Researchers have also found that among female adolescents who reported having vaginal sex first, 31 percent reported having a teen pregnancy, whereas among those who initiated oral-genital sex first, only 8 percent reported having a teen pregnancy (Reese & others, 2013). Thus, how adolescents initiate their sex lives may have positive or negative consequences for their sexual health.
Risk Factors in Adolescent Sexual Behavior Many adolescents are not emotionally prepared to handle sexual experiences, especially in early adolescence (Cai & others, 2018; Donenberg & others, 2018; Ihongbe, Cha, & Masho, 2017). Early sexual activity is linked with risky behaviors Page 347such as drug use, delinquency, and school-related problems (Boisvert, Boislard, & Poulin, 2017; Rivera & others, 2018). A recent study of more than 3,000 Swedish adolescents revealed that sexual intercourse before age 14 was linked to risky behaviors such as an increased number of sexual partners, experience of oral and anal sex, negative health behaviors (smoking, drug and alcohol use), and antisocial behavior (being violent, stealing, running away from home) at 18 years of age (Kastbom & others, 2016). Further, a recent study found that early sexual debut (first sexual intercourse before age 13) was associated with sexual risk taking, substance use, violent victimization, and suicidal thoughts/attempts in both sexual minority (in this study, gay, lesbian, and bisexual adolescents) and heterosexual youth (Lowry, Robin, & Kann, 2017). And in a recent study of Korean adolescent girls, early menarche was linked with earlier initiation of sexual intercourse (Kim & others, 2018).
In addition to having sex in early adolescence, other risk factors for sexual problems in adolescence include contextual factors such as socioeconomic status (SES) and poverty, immigration/ethnic minority status, family/parenting and peer factors, and school-related influences (Simons & others, 2016; Warner, 2018). The percentage of sexually active young adolescents is higher in low-income areas of inner cities (Morrison-Beedy & others, 2013). One study revealed that neighborhood poverty concentrations predicted 15- to 17-year-old girls’ and boys’ sexual initiation (Cubbin & others, 2010). Also, a national survey of 15- to 20-year-olds found that Spanish-speaking immigrant youth were more likely to have a sexual partner age difference of 6 or more years and less likely to use contraception at first sexual intercourse than their native Latino, non-Latino White, and English-speaking Latino immigrant counterparts (Haderxhanaj & others, 2014).
What are some risks associated with early initiation of sexual intercourse?
A number of family factors are associated with sexual risk-taking (Ashcraft & Murray, 2017; Ruiz-Casares & others, 2017). For example, a recent study revealed that adolescents who in the eighth grade reported greater parental knowledge and more family rules about dating were less likely to initiate sex from the eighth to tenth grade (Ethier & others, 2016). Also, a recent study revealed that of a number of parenting practices the factor that best predicted a lower level of risky sexual behavior by adolescents was supportive parenting (Simons & others, 2016). Further, one study found that difficulties and disagreements between Latino adolescents and their parents were linked to the adolescents’ early sex initiation (Cordova & others, 2014). Also, having older sexually active siblings or pregnant/parenting teenage sisters placed adolescent girls at higher risk for pregnancy (Miller, Benson, & Galbraith, 2001).
Peer, school, sport, and religious contexts provide further information about sexual risk taking in adolescents (Choukas-Bradley & Prinstein, 2016). One study found that adolescents who associated with more deviant peers in early adolescence were likely to have more sexual partners at age 16 (Lansford & others, 2010). Also, a research review found that school connectedness was linked to positive sexuality outcomes (Markham & others, 2010). A study of middle school students revealed that better academic achievement was a protective factor in preventing boys and girls from engaging in early sexual intercourse (Laflin, Wang, & Barry, 2008). Also, a recent study found that adolescent males who play sports engage in a higher level of sexual risk taking, while adolescent females who play sports engage in a lower level of sexual risk taking (Lipowski & others, 2016). And a recent study of African American adolescent girls indicated that those who reported that religion was of low or moderate importance to them had a much earlier sexual debut that their counterparts who said that religion was very important or extremely important to them (George Dalmida & others, 2018).
Psychologists are exploring ways to encourage adolescents to make less risky sexual decisions. Here an adolescent participates in an interactive video session developed by Julie Downs and her colleagues at the Department of Social and Decision Making Sciences at Carnegie Mellon University. The videos help adolescents evaluate their responses and decisions in high-risk sexual contexts.
©Michael Ray
Cognitive and personality factors are increasingly implicated in sexual risk taking in adolescence. Weak self-regulation (difficulty controlling one’s emotions and behavior) and impulsiveness are two such factors. Another longitudinal study found that weak self-regulation at 8 to 9 years of age and risk proneness (tendency to seek sensation Page 348and make poor decisions) at 12 to 13 years of age set the stage for sexual risk taking at 16 to 17 years of age (Crockett, Raffaelli, & Shen, 2006). Also, a meta-analysis indicated that the link between impulsivity and risky sexual behavior was likely to be more characteristic of adolescent females than males (Dir, Coskunpinar, & Cyders, 2014).
Contraceptive Use Too many sexually active adolescents still do not use contraceptives, use them inconsistently, or use contraceptive methods that are less effective than others (Chandra-Mouli & others, 2018; Diedrich, Klein, & Peipert, 2017; Fridy & others, 2018; Jaramillo & others, 2017). In 2015, 14 percent of sexually active adolescents did not use any contraceptive method the last time they had sexual intercourse (Kann & others, 2016a). Researchers have found that U.S. adolescents are less likely to use condoms than their European counterparts (Jorgensen & others, 2015).
developmental connection
Conditions, Diseases, and Disorders
What are some good strategies for protecting against HIV and other sexually transmitted infections? Connect to “Physical and Cognitive Development in Early Adulthood.”
Recently, a number of leading medical organizations and experts have recommended that adolescents use long-acting reversible contraception (LARC). These include the Society for Adolescent Health and Medicine (2017), the American Academy of Pediatrics and American College of Obstetrics and Gynecology (Allen & Barlow, 2017), and the World Health Organization (2017). LARC consists of the use of intrauterine devices (IUDs) and contraceptive implants, which have a much lower failure rate and are more effective in preventing unwanted pregnancy than birth control pills and condoms (Diedrich, Klein, & Peipert, 2017; Fridy & others, 2018; Society for Adolescent Health and Medicine, 2017).
Sexually Transmitted Infections Some forms of contraception, such as birth control pills or implants, do not protect against sexually transmitted infections, or STIs. Sexually transmitted infections (STIs) are contracted primarily through sexual contact, including oral-genital and anal-genital contact. Every year more than 3 million American adolescents (about one-fourth of those who are sexually experienced) acquire an STI (Centers for Disease Control and Prevention, 2018). In a single act of unprotected sex with an infected partner, a teenage girl has a 1 percent risk of getting HIV, a 30 percent risk of acquiring genital herpes, and a 50 percent chance of contracting gonorrhea (Glei, 1999). Yet another very widespread STI is chlamydia. We will consider these and other sexually transmitted infections in more detail later.
Adolescent Pregnancy Adolescent pregnancy is another problematic outcome of sexuality in adolescence and requires major efforts to reduce its occurrence (Brindis, 2017; Chandra-Mouli & others, 2018; Fridy & others, 2018; Marseille & others, 2018; Romero & others, 2017; Tevendale & others, 2017). In cross-cultural comparisons, the United States continues to have one of the highest adolescent pregnancy and childbearing rates in the industrialized world, despite a considerable decline during the 1990s. The U.S. adolescent pregnancy rate is eight times as high as that in the Netherlands. Although U.S. adolescents are no more sexually active than their counterparts in the Netherlands, their adolescent pregnancy rate is dramatically higher. In the United States, 82 percent of pregnancies in adolescents 15 to 19 years of age are unintended (Koh, 2014). A cross-cultural comparison found that among 21 countries, the United States had the highest adolescent pregnancy rate among 15- to 19-year-olds and Switzerland the lowest (Sedgh & others, 2015).
Despite the negative comparisons of the United States with many other developed countries, there have been some encouraging trends in U.S. adolescent pregnancy rates. In 2015, the U.S. birth rate for 15- to 19-year-olds was 22.3 births per 1,000 females, the lowest rate ever recorded, which represents a dramatic decrease from the 61.8 births for the same age range in 1991 and down even 8 percent from 2014 (Martin & others, 2017) (see Figure 6). There also has been a substantial decrease in adolescent pregnancies across ethnic groups in recent years. Reasons for the decline include school/community health classes, increased contraceptive Page 349use, and fear of sexually transmitted infections such as AIDS.
Source: Martin, J. A. et al. “Births: Final data for 2015.” National Vital Statistics Reports, 66 (1), 2017, 1.
Ethnic variations characterize birth rates for U.S. adolescents. Latina adolescents are more likely than African American and non-Latina White adolescents to have a child (Martin & others, 2017). Latina and African American adolescent girls who have a child are also more likely to have a second child than are non-Latina White adolescent girls (Rosengard, 2009). And daughters of teenage mothers are at increased risk for teenage childbearing, thus perpetuating an intergenerational cycle (Meade, Kershaw, & Ickovics, 2008).
Adolescent pregnancy creates health risks for both the baby and the mother (Leftwich & Alves, 2017). Infants born to adolescent mothers are more likely to have low birth weights—a prominent factor in infant mortality—as well as neurological problems and childhood illness (Leftwich & Alves, 2017). A recent study assessed the reading and math achievement trajectories of children born to adolescent and non-adolescent mothers with different levels of education (Tang & others, 2016). In this study, higher levels of maternal education were linked to higher academic achievement through the eighth grade. Nonetheless, the achievement of children born to adolescent mothers never reached the levels of children born to adult mothers. Adolescent mothers are more likely to be depressed and to drop out of school than their peers are (Siegel & Brandon, 2014). Although many adolescent mothers resume their education later in life, they generally never catch up economically with women who postpone childbearing until their twenties. Also, a study of African American urban youth found that at 32 years of age, women who had become mothers as teenagers were more likely than non-teen mothers to be unemployed, live in poverty, depend on welfare, and not have completed college (Assini-Meytin & Green, 2015). In this study, at 32 years of age, men who had become fathers as teenagers were more likely than non-teen fathers to be unemployed.
A special concern is repeated adolescent pregnancy. In a recent national study, the percentage of teen births that were repeat births decreased from 2004 (21 percent) to 2015 (17 percent) (Dee & others, 2017). In a recent meta-analysis, use of effective contraception, especially LARC, and education-related factors (higher level of education and school continuation) resulted in a lower incidence of repeated teen pregnancy, while depression and a history of abortion were linked to a higher percentage of repeated teen pregnancy (Maravilla & others, 2017).
Researchers have found that adolescent mothers interact less effectively with their infants than do adult mothers (Leftwich & Alves, 2017). One study revealed that adolescent mothers spent more time negatively interacting and less time in play and positive interactions with their infants than did adult mothers (Riva Crugnola & others, 2014). Also, a recent intervention, “My Baby and Me,” that involved frequent, intensive home visitation coaching sessions with adolescent mothers across three years resulted in improved maternal behavior and child outcomes (Guttentag & others, 2014).
Although the consequences of America’s high rate of adolescent pregnancy are cause for great concern, it often is not pregnancy alone that leads to negative consequences for an adolescent mother and her offspring. Adolescent mothers are more likely to come from low-SES backgrounds (Mollborn, 2017). Many adolescent mothers also were not good students before they became pregnant (Malamitsi-Puchner & Boutsikou, 2006). However, not every adolescent female who bears a child lives a life of poverty and low achievement. Thus, although adolescent pregnancy is a high-risk circumstance, and adolescents who do not become pregnant generally fare better than those who do, some adolescent mothers do well in school and have positive outcomes (Schaffer & others, 2012).
Serious, extensive efforts are needed to help pregnant adolescents and young mothers enhance their educational and occupational opportunities (Carroll, 2018; Craft, Brandt, & Prince, 2016; Mueller & others, 2017; Romero & others, 2017). Adolescent mothers also need help obtaining competent child care and planning for the future.
Adolescents can benefit from age-appropriate family-life education (Barfield, Warner, & Kappeler, 2017; Mueller & others, 2017). Family and consumer science educators teach life skills, such as effective decision making, to adolescents. To read about the work of one family and consumer science educator, see Connecting with Careers. And to learn more about ways to reduce adolescent pregnancy, see Connecting Development to Life.
What are some consequences of adolescent pregnancy?
©Geoff Manasse/Getty ImagesPage 350
connecting with careers
Lynn Blankinship, Family and Consumer Science Educator
Lynn Blankinship is a family and consumer science educator with an undergraduate degree in this field from the University of Arizona. She has taught for more than 20 years, the last 14 at Tucson High Magnet School.
Blankinship has been honored as the Tucson Federation of Teachers Educator of the Year and the Arizona Teacher of the Year. Blankinship especially enjoys teaching life skills to adolescents. One of her favorite activities is having students care for an automated baby that imitates the needs of real babies. She says that this program has a profound impact on students because the baby must be cared for around the clock for the duration of the assignment. Blankinship also coordinates real-world work experiences and training for students in several child-care facilities in the Tucson area.
For more information about what family and consumer science educators do, see the Careers in Life-Span Development appendix.
Lynn Blankinship (center) teaches life skills to students.
Courtesy of Lynn Blankinship
connecting development to life
Reducing Adolescent Pregnancy
One strategy for reducing adolescent pregnancy, called the Teen Outreach Program (TOP), focuses on engaging adolescents in volunteer community service and stimulates discussions that help adolescents appreciate the lessons they learn through volunteerism.
Girls Inc. has four programs that are intended to increase adolescent girls’ motivation to avoid pregnancy until they are mature enough to make responsible decisions about motherhood (Roth & others, 1998). Growing Together, a series of five two-hour workshops for mothers and adolescents, and Will Power/Won’t Power, a series of six two-hour sessions that focus on assertiveness training, are for 12- to 14-year-old girls. For older adolescent girls, Taking Care of Business provides nine sessions that emphasize career planning as well as information about sexuality, reproduction, and contraception. Health Bridge coordinates health and education services—girls can participate in this program as one of their club activities. Girls who participated in these programs were less likely to get pregnant than girls who did not participate (Girls Inc., 1991).
In 2010, the U.S. government launched the Teen Pregnancy Prevention (TPP) program under the direction of the newly created Office of Adolescent Health (Koh, 2014). Currently, a number of studies are being funded by the program in an effort to find ways to reduce the rate of adolescent pregnancy.
The sources and the accuracy of adolescents’ sexual information are linked to adolescent pregnancy. Adolescents can get information about sex from many sources, including parents, siblings, schools, peers, magazines, television, and the Internet. A special concern is the accuracy of sexual information to which adolescents have access on the Internet.
Currently, a major controversy in sex education is whether schools should have an abstinence-only program or a program that emphasizes contraceptive knowledge (Erkut & others, 2013; MacKenzie, Hedge, & Enslin, 2017). Recent research reviews have concluded that abstinence-only programs do not delay the initiation of sexual intercourse and do not reduce HIV risk behaviors (Denford & others, 2017; Jaramillo & others, 2017; Santelli & others, 2017).
Despite the evidence that favors comprehensive sex education, there recently has been an increase in government funding for abstinence-only programs (Donovan, 2017). Also, in some states (Texas and Mississippi, for example), many students still either get abstinence-only or no sex education at all (Campbell, 2016; Pollock, 2017).
Recently, there also has been an increased emphasis in abstinence-only-until-marriage (AOUM) policies and programs. However, a major problem with such policies and programs is that a very large majority of individuals engage in sexual intercourse at some point in adolescence or emerging adulthood while the age of marriage continues to go up (27 for females, 29 for males in the United States) (Society for Adolescent Medicine, 2017).
Based on the information you read earlier about risk factors in adolescent sexual behavior, which segments of the adolescent population would benefit most from the types of sex education programs described here?
Page 351
Review Connect Reflect
LG2 Describe the changes involved in puberty, as well as changes in the brain and sexuality during adolescence.

What are some key aspects of puberty?
What changes typically occur in the brain during adolescence?
What are some important aspects of sexuality in adolescence?


How might adolescent brain development be linked to adolescents’ decisions to engage in sexual activity or to abstain from it?

Reflect Your Own Personal Journey of Life

Did you experience puberty earlier or later than your peers? How did this timing affect your development?

3 Issues in Adolescent Health
LG3 Identify adolescent problems related to health, substance use and abuse, and eating disorders.
Adolescent Health
Substance Use and Abuse
Eating Disorders
Many health experts argue that whether adolescents are healthy depends primarily on their own behavior. To improve adolescent health, adults should aim to (1) increase adolescents’ health-enhancing behaviors, such as eating nutritious foods, exercising, wearing seat belts, and getting adequate sleep; and (2) reduce adolescents’ health-compromising behaviors, such as drug abuse, violence, unprotected sexual intercourse, and dangerous driving.
Adolescence is a critical juncture in the adoption of behaviors that are relevant to health (Coore Desai, Reece, & Shakespeare-Pellington, 2017; Devenish, Hooley, & Mellor, 2017; Oldfield & others, 2018; Yap & others, 2017). Many of the behaviors that are linked to poor health habits and early death in adults begin during adolescence (Blake, 2017; Donatelle & Ketcham, 2018). Conversely, the early formation of healthy behavior patterns, such as regular exercise and a preference for foods low in fat and cholesterol, not only has immediate health benefits but helps in adulthood to delay or prevent disability and mortality from heart disease, stroke, diabetes, and cancer (Hales, 2018; Powers & Dodd, 2017).
Nutrition and Exercise Concerns are growing about adolescents’ nutrition and exercise habits (Donatelle, 2019; Powers & Dodd, 2017; Schiff, 2017, 2019; Smith & Collene, 2019). National data indicated that the percentage of overweight U.S. 12- to 19-year-olds increased from 11 percent in the early 1990s to nearly 20.5 percent in 2014 (Centers for Disease Control and Prevention, 2016). In another study, 12.4 percent of U.S. kindergarten children were obese, but by 14 years of age, 20.8 percent were obese (Cunningham, Kramer, & Narayan, 2014).
A special concern in American culture is the amount of fat we consume. Many of today’s adolescents virtually live on fast-food meals, which are high in fat. A comparison of adolescents in 28 countries found that U.S. and British adolescents were more likely to eat fried food and less likely to eat fruits and vegetables than adolescents in most other countries that were studied (World Health Organization, 2000). The National Youth Risk Survey found that U.S. high school students showed a linear decrease in their intake of fruits and vegetables from 1999 through 2015 (Kann & others, 2016a).
Being obese in adolescence predicts obesity in emerging adulthood. For example, a longitudinal study of more than 8,000 adolescents found that obese adolescents were more likely to develop severe obesity in emerging adulthood than were overweight or normal-weight adolescents (The & others, 2010). In another longitudinal study, the percentage of overweight individuals increased from 20 percent at 14 years of age to 33 percent at 24 years of age (Patton & others, 2011).
Researchers have found that individuals become Page 352less active as they reach and progress through adolescence (Alberga & others, 2012). A national study of U.S. adolescents revealed that physical activity increased until 13 years of age in boys and girls but then declined through 18 years of age (Kahn & others, 2008). A recent national study also found that adolescent girls were much less likely to have engaged in 60 minutes or more of vigorous exercise per day in 5 of the last 7 days (61 percent) than were boys (42 percent) (YRBSS, 2016). Ethnic differences in exercise participation rates of U.S. adolescents also occur, and these rates vary by gender. In the national study just mentioned, non-Latino White boys exercised the most, African American and Latino girls the least (YRBSS, 2016).
Positive physical outcomes of exercise in adolescence include a lower rate of obesity, reduced triglyceride levels, lower blood pressure, and a lower incidence of type II diabetes (Barton & others, 2017; Powers & Howley, 2018; Son & others, 2017; Walton-Fisette & Wuest, 2018; Xie & others, 2017). Also, one study found that adolescents who were high in physical fitness had better connectivity between brain regions than adolescents who were low in physical fitness (Herting & others, 2014). Exercise in adolescence also is linked to other positive outcomes. Higher levels of exercise are related to fewer depressive symptoms in adolescents (Gosmann & others, 2015). In a recent study, a high-intensity exercise program reduced depressive symptoms and improved the moods of depressed adolescents (Carter & others, 2016). In another study, young adolescents who exercised regularly had higher academic achievement (Hashim, Freddy, & Rosmatunisah, 2012). And in a recent research review, among a number of cognitive factors, memory was the factor that most often was improved by exercise in adolescence (Li & others, 2017).
What are some characteristics of adolescents’ exercise patterns?
©Tom Stewart/Corbis/Getty Images
Adolescents’ exercise is increasingly being found to be associated with parenting and peer relationships (Mason & others, 2017; Michaud & others, 2017). One study revealed that family meals during adolescence protected against becoming overweight or obese in adulthood (Berge & others, 2015). Another study revealed that female adolescents’ physical activity was linked to their male and female friends’ physical activity, while male adolescents’ physical activity was associated with their female friends’ physical activity (Sirard & others, 2013).
Researchers have found that screen time is associated with a number of adolescent health problems, including a lower rate of exercise and a higher rate of sedentary behavior (Pearson & others, 2017). In one research review, a higher level of screen-based sedentary behavior was associated with being overweight, having sleep problems, being depressed, and having lower levels of physical activity/fitness and psychological well-being (higher stress levels, for example (Costigan & others, 2013).
What types of interventions and activities have been successful in reducing overweight in adolescents and emerging adults? Research indicates that dietary changes and regular exercise are key components of weight reduction in adolescence and emerging adulthood (Fukerson & others, 2018; Lipsky & others, 2017; Martin & others, 2018; Powers & Howley, 2018). For example, a recent study found that a combination of regular exercise and a diet plan resulted in weight loss and enhanced executive function in adolescents (Xie & others, 2017).
Sleep Like nutrition and exercise, sleep is an important influence on well-being. Might changing sleep patterns in adolescence contribute to adolescents’ health-compromising behaviors? Recently there has been a surge of interest in adolescent sleep patterns (Hoyt & others, 2018; Meltzer, 2017; Palmer & others, 2018; Reddy & others, 2017; Seo & others, 2017; Wheaton & others, 2018). A longitudinal study in which adolescents completed a 24-hour diary every 14 days in ninth, tenth, and twelfth grades found that regardless of how much students studied each day, when the students sacrificed sleep time to study more than usual they had difficulty understanding what was taught in class and were more likely to struggle with class assignments the next day (Gillen-O’Neel, Huynh, & Fuligni, 2013). Also, a recent experimental study indicated that when adolescents’ sleep was restricted to five hours for five nights, then returned to ten hours for two nights, their sustained attention was negatively affected (especially in the early morning) and did not return to baseline levels during recovery (Agostini & others, 2017). Further, researchers have found that adolescents who get less than 7.7 hours of sleep per night on average have more emotional and peer-related problems, higher anxiety, and a higher level of suicidal ideation (Sarchiapone & others, 2014). And a recent national study of more than 10,000 13- to 18-year-olds revealed that later weeknight bedtime, shorter weekend bedtime delay, and both short and long periods of weekend oversleep were linked to increased rates of anxiety, mood, substance abuse, and behavioral disorders (Zhang & others, 2017). Further, in a four-year longitudinal study beginning at 12 years of age, poor sleep patterns (for example, shorter sleep duration and greater daytime sleepiness) at age 12 was associated with an increased likelihood Page 353of drinking alcohol and using marijuana at 16 years of age (Miller, Janssen, & Jackson, 2017). Also, recent Swedish studies revealed that adolescents with a shorter sleep duration were more likely to have more school absences, while shorter sleep duration and greater sleep deficits were linked to having a lower grade point average (Hysing & others, 2015, 2016).
In a recent national survey of youth, only 27 percent of U.S. adolescents got eight or more hours of sleep on an average school night (Kann & others, 2016a). In this study, the percentage of adolescents getting this much sleep on an average school night decreased as they got older (see Figure 7). Also, in other research with more than 270,000 U.S. adolescents from 1991–2012, adolescents were getting less sleep in recent years than in the past (Keyes & others, 2015).
The National Sleep Foundation (2006) conducted a U.S. survey of adolescent sleep patterns. Those who got inadequate sleep (eight hours or less) on school nights were more likely to feel tired or sleepy, to be cranky and irritable, to fall asleep in school, to be in a depressed mood, and to drink caffeinated beverages than their counterparts who got optimal sleep (nine or more hours). Also, a longitudinal study of more than 6,000 adolescents found that sleep problems were linked to subsequent suicidal thoughts and attempts in adolescence and early adulthood (Wong & Brower, 2012). Further, one study found that adolescents who got less than 7.7 hours of sleep per night on average had more emotional and peer-related problems, higher anxiety, and a higher level of suicidal ideation than their peers who got 7.7 hours of sleep or more (Sarchiapone & others, 2014).
Why are adolescents getting too little sleep? Among the reasons given are those involving electronic media, caffeine, and changes in the brain coupled with early school start times (Bartel, Scheeren, & Gradisar, 2018; Owens, 2014). In one study, adolescents averaged engaging in four electronic activities (in some cases, this involved simultaneous use of different devices) after 9 p.m. (Calamaro, Mason, & Ratcliffe, 2009). Engaging in these electronic activities in the evening can replace sleep time, and such media use may increase sleep-disrupting arousal (Cain & Gradisar, 2010). Also, a study of fourth- and seventh-graders found that sleeping near small screens (smartphones, for example), sleeping with a TV in the room, and more screen time were associated with shorter sleep duration in both children and adolescents (Falbe & others, 2015).
Caffeine intake by adolescents appears to be related to inadequate sleep (Owens, 2014). Greater caffeine intake as early as 12 years of age is linked to later sleep onset, shorter sleep duration, and increased daytime sleepiness (Carskadon & Tarokh, 2014). Further, researchers have yet to study the connection between adolescent sleep patterns and high levels of caffeine intake from energy drinks.
Mary Carskadon and her colleagues (2004, 2005, 2011a, b; Crowley & Carskadon, 2010; Tarokh & Carskadon, 2010) have conducted a number of research studies on adolescent sleep patterns. They found that when given the opportunity, adolescents will sleep an average of 9 hours and 25 minutes a night. Most get considerably less than nine hours of sleep, however, especially during the week. This shortfall creates a sleep deficit, which adolescents often attempt to make up on the weekend. The researchers also found that older adolescents tend to be sleepier during the day than younger adolescents. They theorized that this sleepiness was not due to academic work or social pressures. Rather, their research suggests that adolescents’ biological clocks undergo a shift as they get older, delaying their period of sleepiness by about one hour. A delay in the nightly release of the sleep-inducing hormone melatonin, which is produced in the brain’s pineal gland, seems to underlie this shift. Melatonin is secreted at about 9:30 p.m. in younger adolescents and approximately an hour later in older adolescents.
Carskadon concludes that early school starting times may cause grogginess, inattention in class, and poor performance on tests. Based on her research, school officials in Edina, Minnesota, decided to start classes at 8:30 a.m. rather than the usual 7:25 a.m. Since then there have been fewer referrals for discipline problems, and the number of students who report being ill or depressed has decreased. The school system reports that test scores have improved for high school students but not for middle school students. This finding supports Carskadon’s suspicion that early start times are likely to be more stressful for older than for younger adolescents.
In Mary Carskadon’s sleep laboratory at Brown University, an adolescent girl’s brain activity is being monitored. Carskadon (2005) says that in the morning, sleep-deprived adolescents’ “brains are telling them it’s night time . . . and the rest of the world is saying it’s time to go to school” (p. 19).
©Jim LoScalzo
One study found that just a 30-minute delay in school start time was linked to improvements in adolescents’ sleep, alertness, mood, and health (Owens, Belon, & Moss, 2010). In another study, early school start times were linked to a higher vehicle crash rate in adolescent Page 354drivers (Vorona & others, 2014). The American Academy of Pediatrics recommends that schools institute start times from 8:30 to 9:30 a.m. to improve adolescents’ academic performance and quality of life (Adolescent Sleep Working Group, AAP, 2014).
Do sleep patterns change in emerging adulthood? Research indicates that they do (Galambos, Howard, & Maggs, 2011). One study revealed that more than 60 percent of college students were categorized as poor-quality sleepers (Lund & others, 2010). In this study, the weekday bedtimes and rise times of first-year college students were approximately 1 hour and 15 minutes later than those of seniors in high school (Lund & others, 2010). However, the first-year college students had later bedtimes and rise times than third- and fourth-year college students, indicating that at about 20 to 22 years of age, a reverse in the timing of bedtimes and rise times occurs. In another study, consistently low sleep duration in college students was associated with less effective attention the next day (Whiting & Murdock, 2016). Also, in a recent study of college students, a higher level of text messaging (greater number of daily texts, awareness of nighttime cell phone notifications, and compulsion to check nighttime notifications) was linked to a lower level of sleep quality (Murdock, Horissian, & Crichlow-Ball, 2017).
Leading Causes of Death in Adolescence The three leading causes of death in adolescence are unintentional injuries, homicide, and suicide (National Center for Health Statistics, 2018). Almost half of all deaths from 15 to 24 years of age are due to unintentional injuries, the majority of them involving motor vehicle accidents. Risky driving habits, such as speeding, tailgating, and driving under the influence of alcohol or other drugs, may be more important contributors to these accidents than lack of driving experience (White & others, 2018; Williams & others, 2018). In about 50 percent of motor vehicle fatalities involving adolescents, the driver has a blood alcohol level of 0.10 percent—twice the level at which a driver is designated as “under the influence” in some states. Of growing concern is the increasingly common practice of mixing alcohol and energy drinks, which is linked to a higher rate of driving while intoxicated (Wilson & others, 2018). A high rate of intoxication is also found in adolescents who die as pedestrians or while using vehicles other than automobiles.
Homicide is the second leading cause of death in adolescence, especially among African American males (National Center for Health Statistics, 2018). Also notable is the adolescent suicide rate, which has tripled since the 1950s. Suicide accounts for 6 percent of deaths in the 10-to-14 age group and 12 percent of deaths in the 15-to-19 age group. We will discuss suicide in more detail later.
Each year since 1975, Lloyd Johnston and his colleagues at the Institute of Social Research at the University of Michigan have monitored the drug use of America’s high school seniors in a wide range of public and private high schools. Since 1991, they also have surveyed drug use by eighth- and tenth-graders. In 2017, the study surveyed approximately 45,000 secondary school students in 380 public and private schools (Johnston & others, 2018).
In the University of Michigan study, drug use among U.S. secondary school students declined in the 1980s but began to increase in the early 1990s before declining again in the early part of the first decade of the 21st century. However, from 2006 through 2017, overall use of illicit drugs began increasing again, due mainly to an increase in marijuana use by adolescents. In 2006, 36.5 percent of twelfth-graders reported annual use of an illicit drug but in 2017 that figure had increased to 39.9 percent. However, if marijuana use is subtracted from the annual use figures, there has been a significant decline in drug use by adolescents. When marijuana use is deleted, in 2006, 19.2 percent of twelfth-graders used an illicit drug annually, but that figure showed a significant decline to 13.3 percent in 2017 (Johnston & others, 2018). Marijuana is the most widely used illicit drug by adolescents.
The United States continues to have one of the highest rates of adolescent drug use of any industrialized nation. Because of the increased legalization of marijuana use for adults in a number of states, youth are likely to have increased access to the drug and it is expected that marijuana use by adolescents will increase in the future.
developmental connection
Substance Abuse
Does substance abuse increase or decrease in emerging adulthood? Connect to “Physical and Cognitive Development in Early Adulthood.”
Alcohol How extensive is alcohol use by U.S. adolescents? Sizable declines in adolescent alcohol use have occurred in recent years (Johnston & others, 2018). The percentage of U.S. eighth-graders who reported having had any alcohol to drink Page 355in the past 30 days fell from a 1996 high of 26 percent to 8.0 percent in 2017. The 30-day prevalence fell among tenth-graders from 39 percent in 2001 to 19.7 percent in 2017 and among high school seniors from 72 percent in 1980 to 33.2 percent in 2017. Binge drinking (defined in the University of Michigan surveys as having five or more drinks in a row in the last two weeks) by high school seniors declined from 41 percent in 1980 to 19.1 percent in 2015. Binge drinking by eighth- and tenth-graders also has dropped significantly in recent years. A consistent gender difference occurs in binge drinking, with males engaging in this behavior more than females do (Johnston & others, 2018).
A special concern is adolescents who drive while they are under the influence of alcohol or other substances (White & others, 2018; Williams & others, 2018; Wilson & others, 2018). In the University of Michigan Monitoring the Future Study, 30 percent of high school seniors said they had been in a vehicle with a drugged or drinking driver in the past two weeks (Johnston & others, 2008). And in a national study, one in four twelfth-graders reported that they had consumed alcohol mixed with energy drinks in the last 12 months, and this combination was linked to their unsafe driving (Martz, Patrick, & Schulenberg, 2015).
What are some trends in alcohol use by U.S. adolescents?
©Daniel Allan/Getty Images
Smoking Cigarette smoking (in which the active drug is nicotine) has been one of the most serious yet preventable health problems among adolescents and emerging adults (McKelvey & Halpern-Felsher, 2017). Cigarette smoking among U.S. adolescents peaked in 1996 and has declined significantly since then (Johnston & others, 2018). Following peak use in 1996, smoking rates for U.S. eighth-graders have fallen by 50 percent. In 2017, the percentage of twelfth-graders who reported having smoked cigarettes in the last 30 days was 9.7 percent, an 8 percent decrease from 2011, while the rate for tenth-graders was 5.0 percent and the rate for eighth-graders was 1.9 percent. Since the mid-1990s an increasing percentage of adolescents have reported that they perceive cigarette smoking as dangerous, that they disapprove of it, that they are less accepting of being around smokers, and that they prefer to date nonsmokers (Johnston & others, 2018).
E-cigarettes—battery-powered devices with a heating element—produce a vapor that users inhale. In most cases the vapor contains nicotine, but the specific contents of “vape” formulas are not regulated (Barrington-Trimis & others, 2017; Gorukanti & others, 2017). While adolescent cigarette use has decreased significantly in recent years, a substantial number of U.S. adolescents are now vaping nicotine. In the national study just described, in 2017, 11.0 percent of twelfth-graders, 8.2 percent of tenth-graders, and 3.5 percent of eighth-graders vaped nicotine (Johnston & others, 2018). Thus, adolescents currently are vaping nicotine more than they are smoking cigarettes. Also, in a recent meta-analysis of longitudinal studies, it was concluded that when adolescents use e-cigarettes they are at increased risk for subsequently smoking cigarettes (Soneji & others, 2018).
The Roles of Development, Parents, Peers, and Education There are serious consequences when adolescents begin to use drugs early in adolescence or even in childhood (Donatelle & Ketcham, 2018). For example, a study revealed that the onset of alcohol use before age 11 was linked to a higher risk of alcohol dependence in early adulthood (Guttmannova & others, 2012). Another study found that early onset of drinking and a quick progression to drinking to intoxication were linked to drinking problems in high school (Morean & others, 2014). Further, a longitudinal study found that earlier age at first use of alcohol was linked to increased risk of heavy alcohol use in early adulthood (Liang & Chikritzhs, 2015). And another study indicated that early- and rapid-onset trajectories of alcohol, marijuana, and substance use were associated with substance abuse in early adulthood (Nelson, Van Ryzin, & Dishion, 2015).
What are some of the ways that parents influence whether their adolescents take drugs?
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Parents play an important role in preventing adolescent drug abuse (Cruz & others, 2018; Garcia-Huidobro & others, 2018; Pena & others, 2017). Positive relationships with parents and others can reduce adolescents’ drug use (Chassin & others, 2016; Eun & others, 2018). Researchers have found that parental monitoring is linked with a lower incidence of drug use (Wang & others, 2014). For example, a recent study revealed that parental monitoring was linked to a lower level of polysubstance use by adolescents (Chan & others, 2017). Also, in a recent intervention study, Latino parents who participated in a program that emphasized the importance of parental monitoring had adolescents with a lower level of drug use than a control group of adolescents whose parents did not participate in the program (Estrada & others, 2017). A research review concluded that the more frequently adolescents ate dinner with their families, the less likely they were to have substance abuse problems (Sen, 2010).
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connecting through research
What Can Families Do to Reduce Drinking and Smoking by Young Adolescents?
Experimental studies have been conducted to determine whether family programs can reduce drinking and smoking by young adolescents. In one experimental study, 1,326 families with 12- to 14-year-old adolescents living in various parts of the United States were interviewed (Bauman & others, 2002). After the baseline interviews, participants were randomly assigned either to go through the Family Matters program (experimental group) or not to experience the program (control group) (Bauman & others, 2002).
The families assigned to the Family Matters program received four mailings of booklets. Each mailing was followed by a telephone call from a health educator to “encourage participation by all family members, answer any questions, and record information” (Bauman & others, 2002, pp. 36–37). The first booklet focused on the negative consequences of adolescent substance abuse to the family. The second emphasized “supervision, support, communication skills, attachment, time spent together, educational achievement, conflict reduction, and how well adolescence is understood.” The third booklet asked parents to list things they do that might inadvertently encourage their child’s use of tobacco or alcohol, identify rules that might influence the child’s use, and consider ways to monitor use. Then adult family members and the child met “to agree upon rules and sanctions related to adolescent use.” Booklet four dealt with “what the child can do to resist peer and media pressures for use.”
Two follow-up interviews with the parents and adolescents were conducted three months and one year after the experimental group had completed the program. Adolescents in the Family Matters program reported lower alcohol and cigarette use at three months and at one year after the program had been completed. Figure 8 shows the results for alcohol.
FIGURE 8 YOUNG ADOLESCENTS’ REPORTS OF ALCOHOL USE IN THE FAMILY MATTERS PROGRAM. Note that at baseline (before the program started) the young adolescents in the Family Matters program (experimental group) and their counterparts who did not go through the program (control group) reported approximately the same lifetime use of alcohol (slightly higher use by the experimental group). However, three months after the program ended, the experimental group reported lower alcohol use, and this reduction was still present one year after the program had ended, although at a reduced level.
Source: Johnston, L. D., et al. Monitoring the Future: National survey results on drug use 2016. Ann Arbor: Institute for Social Research, University of Michigan, 2017.
The topics covered in the second booklet underscore the importance of parental influence earlier in development. For instance, staying actively involved and establishing an authoritative, as opposed to a neglectful, parenting style early in children’s lives will better ensure that children have a clear understanding of the parents’ level of support and expectations when the children reach adolescence.
Along with parents, peers play a very important role in adolescent substance use (Cambron & others, 2018; Choukas-Bradley & Prinstein, 2016; Strong & others, 2017). For example, a large-scale national study of adolescents indicated that friends’ use of alcohol was a stronger influence on adolescent alcohol use than parental use (Deutsch, Wood, & Slutske, 2018).
Academic success is also a strong buffer for the emergence of drug problems in adolescence (Kendler & others, 2018). In one study, early educational achievement considerably reduced the likelihood that adolescents would develop drug problems (Bachman & others, 2008). But what can families do to educate themselves and their children and reduce adolescent drinking and smoking behavior? To find out, see Connecting Through Research.
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Let’s now examine two eating problems—anorexia nervosa and bulimia nervosa—that are far more common in adolescent girls than boys.
Anorexia Nervosa Although most U.S. girls have been on a diet at some point, slightly less than 1 percent ever develop anorexia nervosa. Anorexia nervosa is an eating disorder that involves the relentless pursuit of thinness through starvation. It is a serious disorder that can lead to death (Pinhas & others, 2017; Westmoreland, Krantz, & Mehler, 2016). Four main characteristics apply to people suffering from anorexia nervosa: (1) weight below 85 percent of what is considered normal for their age and height; (2) an intense fear of gaining weight that does not decrease with weight loss; (3) a distorted image of their body shape (Reville, O’Connor, & Frampton, 2016), and (4) amenorrhea (lack of menstruation) in girls who have reached puberty.
Obsessive thinking about weight and compulsive exercise also are linked to anorexia nervosa (Simpson & others, 2013). Even when they are extremely thin, they see themselves as too fat (Cornelissen & others, 2015). They never think they are thin enough, especially in the abdomen, buttocks, and thighs. They usually weigh themselves frequently, often take their body measurements, and gaze critically at themselves in mirrors.
Anorexia nervosa typically begins in the early to middle adolescent years, often following an episode of dieting and some type of life stress (Fitzpatrick, 2012). It is about 10 times more likely to occur in females than males. When anorexia nervosa does occur in males, the symptoms and other characteristics (such as a distorted body image and family conflict) are usually similar to those reported by females who have the disorder (Ariceli & others, 2005).
Most anorexics are non-Latina White adolescent or young adult females from well-educated middle- and upper-income families and are competitive and high-achieving (Darcy, 2012). They set high standards, become stressed about not being able to reach the standards, and are intensely concerned about how others perceive them (Murray & others, 2017; Stice & others, 2017). Unable to meet these high expectations, they turn to something they can control: their weight. Offspring of mothers with anorexia nervosa are at risk for becoming anorexic themselves (Machado & others, 2014). Problems in family functioning are increasingly being found to be linked to the appearance of anorexia nervosa in adolescent girls (Dimitropoulos & others, 2018; Espie & Eisler, 2015), and research indicates that family therapy is often an effective treatment for adolescent girls with anorexia nervosa (Ganci & others, 2018; Hail & Le Grange, 2018; Hughes & others, 2018).
Anorexia nervosa has become an increasing problem for adolescent girls and young adult women. What are some possible causes of anorexia nervosa?
©Ian Thraves/Alamy
Biology and culture are involved in anorexia nervosa. Genes play an important role in anorexia nervosa (Meyre & others, 2018). Also, the physical effects of dieting may change neural networks and thus sustain the disordered pattern (Scaife & others, 2017). The thin fashion-model image in U.S. culture likely contributes to the incidence of anorexia nervosa (Cazzato & others, 2016). The media portray thin as beautiful in their choice of fashion models, whom many adolescent girls strive to emulate. Social media may also fuel the relentless pursuit of thinness by making it easier for anorexic adolescents to find each other online. A recent study found that having an increase in Facebook friends across two years was linked to enhanced motivation to be thin (Tiggemann & Slater, 2017).
Bulimia Nervosa Whereas anorexics control their weight by restricting food intake, most bulimics cannot. Bulimia nervosa is an eating disorder in which the individual consistently follows a binge-and-purge pattern. The bulimic goes on an eating binge and then purges by self-inducing vomiting or using a laxative. Although many people binge and purge occasionally and some experiment with it, a person is considered to have a serious bulimic disorder only if the episodes occur at least twice a week for three months (Castillo & Weiselberg, 2017).
As with anorexics, most bulimics are preoccupied with food, have a strong fear of becoming overweight, are depressed or anxious, and have a distorted body image (Murray & others, 2017; Stice & others, 2017). One study found that bulimics have difficulty controlling their emotions (Lavender & others, 2014). Like adolescents who are anorexic, bulimics are highly perfectionistic (Lampard & others, 2012). Unlike anorexics, individuals who binge and purge typically fall within a normal weight range, which makes bulimia more difficult to detect.
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Approximately 1 to 2 percent of U.S. women are estimated to develop bulimia nervosa, and about 90 percent of bulimics are women. Bulimia nervosa typically begins in late adolescence or early adulthood. Many women who develop bulimia nervosa were somewhat overweight before the onset of the disorder, and the binge eating often began during an episode of dieting. As with anorexia nervosa, about 70 percent of individuals who develop bulimia nervosa eventually recover from the disorder (Agras & others, 2004). Drug therapy and psychotherapy have been effective in treating anorexia nervosa and bulimia nervosa (Agras & others, 2017). Cognitive behavior therapy has especially been helpful in treating bulimia nervosa (Abreu & Cangelli Filho, 2017; Hail & Le Grange, 2018; Peterson & others, 2017).
Review Connect Reflect
LG3 Identify adolescent problems related to health, substance use and abuse, and eating disorders.

What are key concerns about the health of adolescents?
What are some characteristics of adolescents’ substance use and abuse?
What are the characteristics of the major eating disorders?


In Connecting Through Research, you learned that attachment was one of the things that the Family Matters program emphasized as important in reducing drinking and smoking behavior in adolescents. Do the research findings discussed in the chapter entitled “Socioemotional Development in Infancy” support or contradict this emphasis on early attachment’s effect on development and behavior later in life?

Reflect Your Own Personal Journey of Life

How health-enhancing and health-compromising were your patterns of behavior in adolescence? Explain.

4 Adolescent Cognition
LG4 Explain cognitive changes in adolescence.
Piaget’s Theory
Adolescent Egocentrism
Information Processing
Adolescents’ developing power of thought opens up new cognitive and social horizons. Let’s examine some explanations of how their power of thought develops, beginning with Piaget’s theory (1952).
Jean Piaget proposed that around 7 years of age children enter the concrete operational stage of cognitive development. They can reason logically about concrete events and objects, and they make gains in their ability to classify objects and to reason about the relationships between classes of objects. Around age 11, according to Piaget, the fourth and final stage of cognitive development—the formal operational stage—begins.
developmental connection
Cognitive Theory
Is there a fifth, postformal stage of cognitive development that characterizes young adults? Connect to “Physical and Cognitive Development in Early Adulthood.”
The Formal Operational Stage What are the characteristics of the formal operational stage? Formal operational thought is more abstract than concrete operational thought. Adolescents are no longer limited to actual, concrete experiences as anchors for thought. They can conjure up make-believe situations, abstract propositions, and events that are purely hypothetical, and can try to reason logically about them.
The abstract quality of thinking during the formal operational stage is evident in the adolescent’s verbal problem-solving ability. Whereas the concrete operational thinker needs to see the concrete elements A, B, and C to be able to make the logical Page 359inference that if A = B and B = C, then A = C, the formal operational thinker can solve this problem merely through verbal presentation.
Another indication of the abstract quality of adolescents’ thought is their increased tendency to think about thought itself. One adolescent commented, “I began thinking about why I was thinking what I was. Then I began thinking about why I was thinking about what I was thinking about what I was.” If this sounds abstract, it is, and it characterizes the adolescent’s enhanced focus on thought and its abstract qualities.
Accompanying the abstract nature of formal operational thought is thought full of idealism and possibilities, especially during the beginning of the formal operational stage, when assimilation dominates. Adolescents engage in extended speculation about ideal characteristics—qualities they desire in themselves and in others. Such thoughts often lead adolescents to compare themselves with others in regard to such ideal standards. And their thoughts are often fantasy flights into future possibilities.
Might adolescents’ ability to reason hypothetically and to evaluate what is ideal versus what is real lead them to engage in demonstrations such as this protest related to improving education? What other causes might be attractive to adolescents’ newfound cognitive abilities of hypothetical-deductive reasoning and idealistic thinking?
©Jim West/Alamy
At the same time that adolescents think more abstractly and idealistically, they also think more logically. Children are likely to solve problems through trial and error; adolescents begin to think more as a scientist thinks, devising plans to solve problems and systematically testing solutions. This type of problem solving requires hypothetical-deductive reasoning, which involves creating a hypothesis and deducing its implications, steps that provide ways to test the hypothesis. Thus, formal operational thinkers develop hypotheses about ways to solve problems and then systematically deduce the best path to follow to solve the problem.
Evaluating Piaget’s Theory Researchers have challenged some of Piaget’s ideas about the formal operational stage (Reyna & Zayas, 2014). Among their findings is that there is much more individual variation than Piaget envisioned: Only about one in three young adolescents is a formal operational thinker, and many American adults (and adults in other cultures) never become formal operational thinkers.
Furthermore, education in the logic of science and mathematics promotes the development of formal operational thinking. This point recalls a criticism of Piaget’s theory that suggests culture and education exert stronger influences on cognitive development than Piaget maintained (Petersen & others, 2017; Wagner, 2018).
Piaget’s theory of cognitive development has been challenged on other points as well. Children’s cognitive development is not as stage-like as Piaget envisioned (Siegler, 2017; Wu & Scerif, 2018). Because some cognitive abilities have found to emerge earlier than Piaget thought, and others later, children do not appear to move neatly from one stage to another (Bauer, 2018; Liu & Spelke, 2017). Other evidence casting doubt on the stage notion is that children often show more understanding on one task than on another, similar task.
Many adolescent girls spend long hours in front of the mirror, depleting cans of hairspray, tubes of lipstick, and jars of cosmetics. How might this behavior be related to changes in adolescent cognitive and physical development?
©Image Source/Getty Images
Despite these challenges to Piaget’s ideas, we owe him a tremendous debt (Miller, 2016). Piaget was the founder of the present field of cognitive development, and he developed a long list of masterful concepts of enduring power and fascination: assimilation, accommodation, object permanence, egocentrism, conservation, and others. Psychologists also owe him the current vision of children as active, constructive thinkers. And they are indebted to him for creating a theory that has generated a huge volume of research on children’s cognitive development (Miller, 2016).
Piaget also was a genius when it came to observing children. His careful observations demonstrated inventive ways to discover how children act on and adapt to their world. He showed us how children need to make their experiences fit their schemes yet simultaneously adapt their schemes to accommodate their experiences. And Piaget revealed how cognitive change is likely to occur if the context is structured to allow gradual movement to the next higher level.
Adolescent egocentrism is the heightened self-consciousness of adolescents. David Elkind (1976) points out that adolescent egocentrism has two key components—the imaginary audience and personal fable. The imaginary audience is reflected in adolescents’ belief that others are as interested in them as they themselves Page 360are, as well as attention-getting behavior—attempts to be noticed, visible, and “on stage.” For example, an eighth-grade boy might walk into a classroom and think that all eyes are riveted on his spotty complexion. Adolescents sense that they are “on stage” in early adolescence, believing they are the main actors and all others are the audience.
According to Elkind, the personal fable is the part of adolescent egocentrism involving a sense of uniqueness and invincibility (or invulnerability). For example, 13-year-old Adrienne says this about herself: “No one understands me, particularly my parents. They have no idea of what I am feeling.” Adolescents’ sense of personal uniqueness makes them believe that no one can understand how they really feel. As part of their effort to retain a sense of personal uniqueness, adolescents might craft a story about the self that is filled with fantasy, immersing themselves in a world that is far removed from reality. Personal fables frequently show up in adolescent diaries.
Might frequent use of social media, such as Facebook, increase adolescents’ egocentrism?
©Brendan O’Sullivan/Photolibrary/Getty Images
Adolescents often have been portrayed as having a sense of invincibility or invulnerability. For example, during a conversation with a girl who is the same age, 14-year-old Margaret says, “Are you kidding? I won’t get pregnant.” This sense of invincibility may lead adolescents to believe that they themselves are invulnerable to dangers and catastrophes (such as deadly car wrecks) that happen to other people. As a result, some adolescents engage in risky behaviors such as drag racing, drug use, suicide attempts, and having sexual intercourse without using contraceptives or barriers against STIs (Alberts, Elkind, & Ginsberg, 2007).
developmental connection
Cognitive Theory
Piaget described a form of egocentrism that characterizes young children. Connect to “Physical and Cognitive Development in Early Childhood.”
Might social media be an amplification tool for adolescent egocentrism? Earlier generations of adolescents did not have social media to connect with large numbers of people; instead, they connected with fewer people, either in person or via telephone. Might today’s teens be drawn to social media and its virtually unlimited friend base to express their imaginary audience and sense of uniqueness? One analysis concluded that amassing a large number of friends (audience) may help to validate adolescents’ perception that their life is on stage and everyone is watching them (Psychster Inc, 2010). A recent meta-analysis concluded that a greater use of social networking sites was linked to a higher level of narcissism (Gnambs & Appel, 2018).
developmental connection
The Brain
The prefrontal cortex is the location in the brain where much of executive function occurs. Connect to “Physical and Cognitive Development in Early Childhood.”
What about having a sense of invulnerability—is that aspect of adolescent egocentrism as accurate as Elkind argues? An increasing number of research studies suggest that rather than perceiving themselves to be invulnerable, adolescents tend to portray themselves as vulnerable to experiencing a premature death (Reyna & Rivers, 2008). For example, in one study, 12- to 18-year-olds were asked about their chances of dying in the next year and prior to age 20 (Fischhoff & others, 2010). The adolescents greatly overestimated their chance of dying prematurely.
Deanna Kuhn (2009) identified some important characteristics of adolescents’ information processing and thinking. In her view, in the later years of childhood and continuing in adolescence, individuals approach cognitive levels that may or may not be achieved, in contrast to the largely universal cognitive levels that young children attain. By adolescence, considerable variation in cognitive functioning is present across individuals. This variability supports the argument that adolescents are producers of their own development to a greater extent than are children.
Kuhn (2009) further argues that the most important cognitive change in adolescence is improvement in executive function—an umbrella-like concept that consists of a number of higher-level cognitive processes linked to the development of the prefrontal cortex (Crone, Peters, & Steinbeis, 2018; Gerst & others, 2017). Executive function involves managing one’s thoughts to engage in goal-directed behavior and to exercise self-control (Bardikoff & Sabbagh, 2017; Knapp & Morton, 2017; Wiebe & Karbach, 2018). Our further coverage of executive function in adolescence focuses on cognitive control, decision making, and critical thinking.
Cognitive Control Earlier you read about the increase Page 361in cognitive control that occurs in middle and late childhood. Recall that cognitive control involves effective control in a number of areas, including controlling attention, reducing interfering thoughts, and being cognitively flexible (Stewart & others, 2017). Cognitive control continues to increase in adolescence and emerging adulthood (Chevalier, Dauvier, & Blaye, 2018; Romer, Reyna, & Satterthwaite, 2017; Somerville, 2016).
Think about all the times adolescents need to engage in cognitive control, such as the following situations (Galinsky, 2010):

making a real effort to stick with a task, avoiding interfering thoughts or environmental events, and instead doing what is most effective;
stopping and thinking before acting to avoid blurting out something that a minute or two later they wished they hadn’t said;
continuing to work on something that is important but boring when there is something a lot more fun to do, inhibiting their behavior and doing the boring but important task, saying to themselves, “I have to show the self-discipline to finish this.”

What are some different aspects of cognitive control that can benefit adolescents’ development?
©DreamPictures/Taxi/Getty Images
Control Attention and Reduce Interfering Thoughts Controlling attention is a key aspect of learning and thinking in adolescence and emerging adulthood (Lau & Waters, 2017; Mueller & others, 2017). Distractions that can interfere with attention in adolescence and emerging adulthood come from the external environment (other students talking while the student is trying to listen to a lecture, or the student turning on a laptop or tablet PC during a lecture and looking at a new friend request on Facebook, for example) or intrusive distractions from competing thoughts in the individual’s mind. Self-oriented thoughts, such as worrying, self-doubt, and intense emotionally laden thoughts may especially interfere with focusing attention on thinking tasks (Gillig & Sanders, 2011).
Be Cognitively Flexible Cognitive flexibility involves being aware that options and alternatives are available and adapting to the situation (Buttelmann & Karbach, 2017; Wang, Ye, & Degol, 2017). Before adolescents and emerging adults adapt their behavior in a situation, they must be aware that they need to change their way of thinking and be motivated to do so (Gopnik & others, 2018). Having confidence in their ability to adapt their thinking to a particular situation, an aspect of self-efficacy, also is important in being cognitively flexible (Bandura, 2012).
Decision Making Adolescence is a time of increased decision making—which friends to choose; which person to date; whether to have sex, buy a car, go to college, and so on (Helm & Reyna, 2018; Meschkow & others, 2018; Reyna, 2018; Romer, Reyna, & Satterthwaite, 2017; Steinberg & others, 2018; van den Bos & Hertwig, 2017). How competent are adolescents at making decisions? Older adolescents are described as more competent than younger adolescents, who in turn are more competent than children (Keating, 1990). Compared with children, young adolescents are more likely to generate different options, examine a situation from a variety of perspectives, anticipate the consequences of decisions, and consider the credibility of sources.
Most people make better decisions when they are calm than when they are emotionally aroused. That may especially be true for adolescents, who have a tendency to be emotionally intense (Cohen & Casey, 2017). The same adolescent who makes a wise decision when calm may make an unwise decision when emotionally aroused. In the heat of the moment, emotions may overwhelm decision-making ability (Goddings & Mills, 2017).
How do emotions and social contexts influence adolescents’ decision making?
©JodiJacobson/E+/Getty Images
The social context plays a key role in adolescent decision making (Breiner & others, 2018; Sherman, Steinberg, & Chein, 2018; Silva & others, 2017). For example, adolescents’ willingness to make risky decisions is more likely to occur in contexts where substances and other temptations are readily available (Helm & Reyna, 2018; Meschkow & others, 2018; Reyna, 2018; Reyna & Rivers, 2008). Recent research reveals that the presence of peers in risk-taking situations increases the likelihood that adolescents will make risky decisions (Silva & others, 2017; Steinberg, 2015a, b). In a recent study, adolescents took greater risks and showed stronger Page 362preference for immediate rewards when they were with three same-aged peers than when they were alone (Silva, Chein, & Steinberg, 2016).
To better understand adolescent decision making, Valerie Reyna and her colleagues (Helm & Reyna, 2018; Meschkow & othes, 2018; Reyna, 2018; Reyna & Farley, 2006; Reyna & others, 2011, 2015, 2017; Romer, Reyna, & Satterthwaite, 2017) have proposed the fuzzy-trace theory dual-process model, which states that decision making is influenced by two cognitive systems—“verbatim” analytical (literal and precise) and gist-based intuitional (simple bottom-line meaning)—which operate in parallel. Basing judgments and decisions on simple gist is viewed as more beneficial than analytical thinking to adolescents’ decision making. In this view, adolescents don’t benefit from engaging in reflective, detailed, higher-level cognitive analysis about a decision, especially in high-risk, real-world contexts where they would get bogged down in trivial detail. In such contexts, adolescents need to rely on their awareness that some circumstances are simply so dangerous that they must be avoided at all costs.
In risky situations it is important for an adolescent to quickly get the gist, or meaning, of what is happening and glean that the situation is a dangerous context, which can cue personal values that will protect the adolescent from making a risky decision (Helm, McCormick, & Reyna, 2018; Helm & Reyna, 2018; Meschkow & others, 2018; Rahimi-Golkhandan & others, 2017; Reyna, 2018; Reyna & others, 2011, 2015; Romer, Reyna, & Satterthwaite, 2017). An experiment showed that encouraging gist-based thinking about risks (along with factual information) reduced self-reported risk taking up to one year after exposure to the curriculum (Reyna & Mills, 2014). However, some experts on adolescent cognition argue that in many cases adolescents benefit from both analytical and experiential systems (Kuhn, 2009).
Adolescents need more opportunities to practice and discuss realistic decision making. Many real-world decisions on matters such as sex, drugs, and daredevil driving occur in an atmosphere of stress that includes time constraints and emotional involvement. One strategy for improving adolescent decision making is to provide more opportunities for them to engage in role playing and peer group problem solving.
Critical Thinking Adolescence is an important transitional period in the development of critical thinking (Keating, 1990). In one study of fifth-, eighth-, and eleventh-graders, critical thinking increased with age but still occurred in only 43 percent of even the eleventh-graders, and many adolescents showed self-serving biases in their reasoning.
If fundamental skills (such as literacy and math skills) are not developed during childhood, critical-thinking skills are unlikely to mature in adolescence. For the subset of adolescents who lack such fundamental skills, potential gains in adolescent thinking are unlikely. For other adolescents, however, cognitive changes that allow improved critical thinking in adolescence include the following: (1) increased speed, automaticity, and capacity of information processing, which free cognitive resources for other purposes; (2) more breadth of content knowledge in a variety of domains; (3) increased ability to construct new combinations of knowledge; and (4) a greater range and more spontaneous use of strategies or procedures for applying or obtaining knowledge, such as planning, considering alternatives, and cognitive monitoring.
Review Connect Reflect
LG4 Explain cognitive changes in adolescence.

What is Piaget’s theory of adolescent cognitive development?
What is adolescent egocentrism?
What are some important aspects of information processing in adolescence?


Egocentrism was also mentioned earlier in the context of early childhood cognitive development. How is adolescent egocentrism similar to or different from egocentrism in early childhood?

Reflect Your Own Personal Journey of Life

Evaluate the level of your thinking as you made the transition to adolescence and through adolescence. Does Piaget’s stage of formal operational thinking accurately describe the changes that occurred in your thinking? Explain.

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5 Schools
LG5 Summarize some key aspects of how schools influence adolescent development.
The Transition to Middle or Junior High School
Effective Schools for Young Adolescents
High School
Extracurricular Activities
Service Learning
What is the transition from elementary to middle or junior high school like? What are the characteristics of effective schools for adolescents? How can adolescents benefit from service learning?
The first year of middle school or junior high school can be difficult for many students (Wigfield, Rosenzweig, & Eccles, 2017; Wigfield, Tonks, & Klauda, 2016). For example, in one study of the transition from sixth grade in an elementary school to seventh grade in a junior high school, adolescents’ perceptions of the quality of their school life plunged in the seventh grade (Hirsch & Rapkin, 1987). Compared with their earlier feelings as sixth-graders, the seventh-graders were less satisfied with school, were less committed to school, and liked their teachers less. The drop in school satisfaction occurred regardless of how academically successful the students were. The transition to middle or junior high school is less stressful when students have positive relationships with friends and go through the transition in team-oriented schools where 20 to 30 students take the same classes together (Hawkins & Berndt, 1985).
The transition to middle or junior high school takes place at a time when many changes—in the individual, in the family, and in school—are occurring simultaneously (Wigfield & others, 2015; Wigfield, Rosenzweig, & Eccles, 2017; Wigfield, Tonks, & Klauda, 2016). These changes include puberty and related concerns about body image; the emergence of at least some aspects of formal operational thought and changes in social cognition; increased responsibility and decreased dependency on parents; change to a larger, more impersonal school structure; change from one teacher to many teachers and from a small, homogeneous set of peers to a larger, more heterogeneous set of peers; and an increased focus on achievement and performance. Moreover, when students make the transition to middle or junior high school, they experience the top-dog phenomenon, moving from being the oldest, biggest, and most powerful students in the elementary school to being the youngest, smallest, and least powerful students in the middle or junior high school.
The transition from elementary to middle or junior high school occurs at the same time as a number of other developmental changes. What are some of these other developmental changes?
The transition to middle or junior high school also can have positive aspects. Students are more likely to feel grown up, have more subjects from which to select, have more opportunities to spend time with peers and locate compatible friends, and enjoy increased independence from direct parental monitoring. They also may be more challenged intellectually by academic work.
Critics argue that middle and junior high schools should offer activities that reflect a wide range of individual differences in biological and psychological development among young adolescents. In 1989 the Carnegie Corporation issued an extremely negative evaluation of U.S. middle schools. It concluded that most young adolescents attended massive, impersonal schools; were taught from irrelevant curricula; trusted few adults in school; and lacked access to health care and counseling. It recommended that the nation develop smaller “communities” or “houses” to lessen the impersonal nature of large middle schools, have lower student-to-counselor ratios (10 to 1 instead of several hundred to 1), involve parents and community leaders in schools, develop new curricula, have teachers team teach in more flexibly designed curriculum blocks that integrate several disciplines, boost students’ health and fitness with more in-school programs, and help students who need public health care to get it. Twenty years later, experts are still finding that middle schools throughout the nation need a major redesign if they are to be effective in educating adolescents (Roeser, 2016; Wigfield & others, 2015).
To read about one individual whose main career focus is improving middle school students’ learning and education, see Connecting with Careers.
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connecting with careers
Katherine McMillan Culp, Research Scientist at an Educational Center
Katherine McMillan Culp wanted mainly to live in New York City when she graduated from college and became a receptionist at a center that focused on children and technology. More than 20 years later she is leading research projects at the center (Center for Children and Technology). Not long after her receptionist job, she combined work at the center with graduate school at Columbia University. Culp became especially interested in how content and instruction can best be created to link with the developmental level of children and adolescents.
Today she holds the position of principal research scientist at Education Development Center, directing a number of projects. One of her main current interests is middle school students’ science learning. In this area, she consults with game designers, teachers, and policy makers to improve their understanding of how adolescents think and learn.
Her advice to anyone wanting to do this type of work outside of academia is to get the best education and training possible, then become connected with schools, work with teachers, and obtain experience related to practical problems involved with schools and learning (Culp, 2012).
Just as there are concerns about U.S. middle school education, so are there concerns about U.S. high school education (Kitsantas & Cleary, 2016). A recent analysis indicated that only 25 percent of U.S. high school graduates have the academic skills to succeed in college (Bill & Melinda Gates Foundation, 2017). Not only are many high school graduates poorly prepared for college, they also are poorly prepared for the demands of the modern, high-performance workplace (Bill & Melinda Gates Foundation, 2018).
Critics stress that in many high schools expectations for success and standards for learning are too low. Critics also argue that too often high schools foster passivity and that schools should create a variety of pathways for students to achieve an identity. Many students graduate from high school with inadequate reading, writing, and math skills—including many who go on to college and must enroll in remediation classes there. Other students drop out of high school and do not have skills that will allow them to obtain decent jobs, much less to be informed citizens.
The transition to high school can have problems just as the transition to middle school does. For example, high schools are often even larger, more bureaucratic, and more impersonal than middle schools are; there isn’t much opportunity for students and teachers to get to know each other, which can lead to distrust; and teachers rarely make content relevant to students’ interests (Eccles & Roeser, 2016). Such experiences likely undermine the motivation of students.
Robert Crosnoe’s (2011) book, Fitting In, Standing Out, highlighted another major problem with U.S. high schools: how the negative social aspects of adolescents’ lives undermine their academic achievement. In his view, adolescents become immersed in complex peer group cultures that demand conformity. High school is supposed to be about getting an education, but for many youth it is about navigating the social worlds of peer relations that may or may not value education and academic achievement. Adolescents who fail to fit in, especially those who are obese or gay, become stigmatized. Crosnoe recommends increased school counseling services, expanded extracurricular activities, and improved parental monitoring to reduce such problems (Crosnoe & Benner, 2015).
Dropout Rates Yet another concern about U.S. high schools involves students dropping out of school. In the last half of the twentieth century and the first decade of the twenty-first century, U.S. high school dropout rates declined (National Center for Education Statistics, 2017). In the 1940s, more than half of U.S. 16- to 24-year-olds had dropped out of school; by 2015, this figure had decreased to 5.9 percent. The dropout rate of Latino adolescents remains high, although it has been decreasing considerably in the twenty-first century (from 27.8 percent in 2000 to 9.2 percent in 2016). The lowest dropout rate in 2015 was for Asian American adolescents Page 365(2.1 percent), followed by non-Latino White adolescents (4.6 percent), African American adolescents (6.5 percent), and Latino adolescents
(9.2 percent) (National Center for Education Statistics, 2017).
National data on Native American adolescents are inadequate because statistics have been collected sporadically and/or from small samples. However, there are some indications that Native American adolescents may have the highest school dropout rate.
Gender differences have characterized U.S. dropout rates for many decades, but they have been narrowing in recent years. In 2015, the dropout rate for males was 6.3 percent and for females it was 5.4 percent (National Center for Education Statistics, 2017).
The average U.S. high school dropout rates just described mask some very high dropout rates in low-income areas of inner cities. For example, in cities such as Detroit, Cleveland, and Chicago, dropout rates are higher than 50 percent. Also, the percentages cited earlier are for 16- to 24-year-olds. When dropout rates are calculated in terms of students who do not graduate from high school within four years, the percentage of students who drop out is also much higher. Thus, in considering high school dropout rates, it is important to examine age, the number of years it takes to complete high school, and various contexts including ethnicity, gender, and school location.
An important educational goal is to increase the high school graduation rate of Native youth. An excellent strategy to accomplish this goal is high quality early childhood educational programs such as this one at St. Bonaventure Indian School on the Navajo Nation in Thoreau, New Mexico.
©Jim West/Alamy
Students drop out of school for many reasons (Dupere & others, 2015). In one study, almost 50 percent of the dropouts cited school-related reasons for leaving school, such as not liking school or being expelled or suspended (Rumberger, 1983). Twenty percent of the dropouts (but 40 percent of the Latino students) cited economic reasons for leaving school. One-third of the female students dropped out for personal reasons such as pregnancy or marriage.
According to a research review, the most effective programs to discourage dropping out of high school provide early intervention for reading problems, tutoring, counseling, and mentoring (Lehr & others, 2003). Clearly, then, early detection of children’s school-related difficulties and getting children engaged with school in positive ways are important strategies for reducing the dropout rate (Crosnoe, Bonazzo, & Wu, 2015).
One program that has been very effective in reducing school dropout rates is “I Have a Dream” (IHAD), an innovative, comprehensive, long-term dropout prevention program administered by the National “I Have a Dream” Foundation in New York (“I Have a Dream” Foundation, 2017). It has grown to encompass more than 180 projects in 64 cities and 28 states plus Washington, DC, and New Zealand, serving more than 16,000 children (“I Have a Dream” Foundation, 2017). Local IHAD projects around the country “adopt” entire grades (usually the third or fourth) from public elementary schools, or corresponding age cohorts from public housing developments. These children—“Dreamers”—are then provided with a program of academic, social, cultural, and recreational activities throughout their elementary, middle school, and high school years. Evaluations of IHAD programs have found improvements in grades, test scores, and school attendance, as well as a reduction in behavioral problems among Dreamers (Davis, Hyatt, & Arrasmith, 1998).
Adolescents in U.S. schools usually can choose from a wide array of extracurricular activities in addition to their academic courses. These adult-sanctioned activities typically occur during the after-school hours and can be sponsored either by the school or by the community. They include such diverse activities as sports, academic clubs, band, drama, and math clubs. Researchers have found that participation in extracurricular activities is linked to higher grades, greater school engagement, less likelihood of dropping out of school, improved probability of going to college, higher self-esteem, and lower rates of depression, delinquency, and substance abuse (Denault & Guay, 2017; Simpkins, Fredricks, & Eccles, 2015; Wigfield & others, 2015). A recent study revealed that immigrant adolescents who participated in extracurricular activities improved their academic achievement and increased Page 366their school engagement (Camacho & Fuligni, 2015). Adolescents gain more benefit from a breadth of extracurricular activities than from focusing on a single extracurricular activity.
These adolescents are participating in the “I Have a Dream” (IHAD) Program, a comprehensive, long-term dropout prevention program that has been very successful. What are some other strategies for reducing high school dropout rates?
Courtesy of “I Have a Dream” Foundation of Boulder County (www.ihadboulder.org)
Of course, the quality of the extracurricular activities matters (Simpkins, Fredricks, & Eccles, 2015). High-quality extracurricular activities that are likely to promote positive adolescent development provide competent, supportive adult mentors; opportunities for increasing school connectedness; challenging and meaningful activities; and opportunities for improving skills.
What are some of the positive effects of service learning?
©Ariel Skelley/Blend Images
Service learning is a form of education that promotes social responsibility and service to the community. In service learning, adolescents engage in activities such as tutoring, helping older adults, working in a hospital, assisting at a child-care center, or cleaning up a vacant lot to make a play area. An important goal of service learning is that adolescents become less self-centered and more strongly motivated to help others (Hart, Goel, & Atkins, 2017; Hart & van Goethem, 2017; Hart & others, 2017; Kackar-Cam & Schmidt, 2014). Service learning is often more effective when two conditions are met (Nucci, 2006): (1) giving students some degree of choice in the service activities in which they participate, and (2) providing students opportunities to reflect about their participation.
Researchers have found that service learning benefits adolescents in a number of ways (Hart & others, 2017). Improvements in adolescent development related to service learning include higher grades in school, increased goal setting, higher self-esteem, and a greater sense of being able to make a difference for others (Hart & van Goethem, 2017). Also, one study revealed that adolescents’ volunteer activities provided opportunities to explore and reason about moral issues (van Goethem & others, 2012).
Review Connect Reflect
LG5 Summarize some key aspects of how schools influence adolescent development.

What is the transition to middle or junior high school like?
What are some characteristics of effective schools for young adolescents?
What are some important things to know about high school dropouts and improving high schools?
How does participation in extracurricular activities influence adolescent development?
What is service learning, and how does it affect adolescent development?


Compare the optimal school learning environments for adolescents described in this chapter with those described for younger children in previous chapters. Aside from age-appropriate curricula, what else is similar or different?

Reflect Your Own Personal Journey of Life

What was your middle or junior high school like? How did it measure up to the Carnegie Corporation’s recommendations?

topical connections looking forward
From 18 to 25 years of age, individuals make a transition from adolescence to adulthood. This transitional period, called emerging adulthood, is characterized by identity exploration, instability, and awareness of possibilities. Individuals often reach the peak of their physical skills between 19 and 26 years of age, followed by declining physical development during the early thirties. Cognitive development becomes more pragmatic and realistic, as well as more reflective and relativistic. Work becomes a more central aspect of individuals’ lives.
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reach your learning goals
Physical and Cognitive Development in Adolescence
1 The Nature of Adolescence
LG1 Discuss the nature of adolescence.

Many stereotypes of adolescents are too negative. Most adolescents today successfully negotiate the path from childhood to adulthood. However, too many of today’s adolescents are not provided with adequate opportunities and support to become competent adults. It is important to view adolescents as a heterogeneous group because different portraits of adolescents emerge, depending on the particular set of adolescents being described.
Social policy regarding adolescents too often has focused on health-compromising behaviors and not enough on strength-based approaches. Adolescents need more caring adults in their lives.

2 Physical Changes
LG2 Describe the changes involved in puberty, as well as changes in the brain and sexuality during adolescence.
The Brain
Adolescent Sexuality

Puberty is a period of rapid physical maturation involving hormonal and bodily changes that occur primarily during early adolescence. Determinants of pubertal timing include nutrition, health, and heredity. The pubertal growth spurt begins at an average age of 9 years for girls and 11 for boys, reaching a peak at 11½ for girls and 13½ for boys. Individual variation in pubertal changes is substantial.
Adolescents show considerable interest in their body image, with girls having more negative body images than boys do. For boys, early maturation brings benefits, at least during early adolescence. Early-maturing girls are vulnerable to a number of risks.
Changes in the brain during adolescence involve the thickening of the corpus callosum and a gap in maturation between the limbic system and the prefrontal cortex, which functions in reasoning and self-regulation.
Adolescence is a time of sexual exploration and sexual experimentation. Having sexual intercourse in early adolescence is associated with negative developmental outcomes.
Contraceptive use by adolescents is increasing. About one in four sexually experienced adolescents acquires a sexually transmitted infection (STI). The adolescent pregnancy rate is higher in the United States than in other industrialized nations, but the U.S. rate of adolescent pregnancy has been decreasing in recent years.

3 Issues in Adolescent Health
LG3 Identify adolescent problems related to health, substance use and abuse, and eating disorders.
Adolescent Health
Substance Use and Abuse
Eating Disorders

Adolescence is a critical juncture in health because many of the factors related to poor health habits and early death in the adult years begin during adolescence. Poor nutrition, lack of exercise, and inadequate sleep are concerns. The three leading causes of death in adolescence are unintentional injuries, homicide, and suicide.
Despite recent declines, the United States has one of the highest rates of adolescent illicit drug use of any industrialized nation. Alcohol abuse is a major adolescent problem, although its rate has been dropping in recent years, as has the rate of cigarette smoking. Parents, peers, social support, and educational success play important roles in determining whether adolescents take drugs.
Eating disorders have increased in adolescence, along with the percentage of adolescents who are overweight. Two eating disorders that may emerge in adolescence are anorexia nervosa and bulimia nervosa. Anorexia nervosa typically starts in the early to middle adolescent years following a dieting episode and involves the relentless pursuit of thinness through starvation. Bulimia nervosa involves a binge-and-purge pattern, and bulimics (unlike anorexics) typically fall within a normal weight range.

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4 Adolescent Cognition
LG4 Explain cognitive changes in adolescence.
Piaget’s Theory
Adolescent Egocentrism
Information Processing

During the formal operational stage, Piaget’s fourth stage of cognitive development, thinking becomes more abstract, idealistic, and logical than during the concrete operational stage. However, many adolescents are not formal operational thinkers but are consolidating their concrete operational thought.
Elkind describes adolescent egocentrism as the heightened self-consciousness of adolescents that consists of two parts: the imaginary audience and the personal fable. Recent research questions whether adolescents perceive themselves to be invulnerable.
Adolescence is characterized by a number of advances in executive function. Cognitive control involves effective control and flexible thinking in a number of areas, including controlling attention, reducing interfering thoughts, remaining cognitively flexible, making decisions, and thinking critically.

5 Schools
LG5 Summarize some key aspects of how schools influence adolescent development.
The Transition to Middle or Junior High School
Effective Schools for
Young Adolescents
High School
Extracurricular Activities
Service Learning

The transition to middle or junior high school coincides with many social, familial, and individual changes in the adolescent’s life, and this transition is often stressful. One source of stress is the move from the top-dog position to the lowest position in school.
Some critics argue that a major redesign of U.S. middle schools is needed. Critics say that U.S. high schools foster passivity and do not develop students’ academic skills adequately. Characteristics of effective schools include lower student-to-counselor ratios, involvement of parents and community leaders in schools, team teaching, and efforts to boost students’ health and fitness.
A number of strategies have been proposed for improving U.S. high schools, including raising expectations and providing better support. The overall high school dropout rate declined considerably in the last half of the twentieth century, but the dropout rates among Latino and Native American youth remain very high.
Participation in extracurricular activities is associated with positive academic and psychological outcomes. Adolescents benefit from participating in a variety of extracurricular activities; the quality of the activities also matters.
Service learning, a form of education that promotes social responsibility and service to the community, has been linked with positive benefits for adolescents such as higher grades, increased goal setting, and improved self-esteem.

key terms
adolescent egocentrism
anorexia nervosa
bulimia nervosa
cognitive control
corpus callosum
fuzzy-trace theory dual-process model
hypothetical-deductive reasoning
imaginary audience
limbic system
personal fable
service learning
sexually transmitted infections (STIs)
top-dog phenomenon
key people
David Elkind
Deanna Kuhn
Lloyd Johnston
Jean Piaget
Valerie Reyna

Link (webpage):
Course Outcomes (CO): 1, 3, 4, 5
chapter 1
chapter outline
1 The Life-Span Perspective
Learning Goal 1 Discuss the distinctive features of a life-span perspective on development.
The Importance of Studying Life-Span Development
Characteristics of the Life-Span Perspective
Some Contemporary Concerns
2 The Nature of Development
Learning Goal 2 Identify the most important processes, periods, and issues in development.
Biological, Cognitive, and Socioemotional Processes
Periods of Development
The Significance of Age
Developmental Issues
3 Theories of Development
Learning Goal 3 Describe the main theories of human development.
Psychoanalytic Theories
Cognitive Theories
Behavioral and Social Cognitive Theories
Ethological Theory
Ecological Theory
An Eclectic Theoretical Orientation
4 Research on Life-Span Development
Learning Goal 4 Explain how research on life-span development is conducted.
Methods for Collecting Data
Research Designs
Time Span of Research
Conducting Ethical Research
Minimizing Bias
©Ariel Skelley/Blend Images LLC
Page 3
Ted Kaczynski sprinted through high school, not bothering with his junior year and making only passing efforts at social contact. Off to Harvard at age 16, Kaczynski was a loner during his college years.
One of his roommates at Harvard said that he avoided people by quickly shuffling by them and slamming the door behind him. After obtaining his Ph.D. in mathematics at the University of Michigan, Kaczynski became a professor at the University of California at Berkeley. His colleagues there remember him as hiding from social contact—no friends, no allies, no networking.
Ted Kaczynski, the convicted Unabomber, traced his difficulties to growing up as a genius in a kid’s body and not fitting in when he was a child.©Seanna O’Sullivan
After several years at Berkeley, Kaczynski resigned and moved to a rural area of Montana where he lived as a hermit in a crude shack for 25 years. Town residents described him as a bearded eccentric. Kaczynski traced his own difficulties to growing up as a genius in a kid’s body and sticking out like a sore thumb in his surroundings as a child. In 1996, he was arrested and charged as the notorious Unabomber, America’s most-wanted killer. Over the course of 17 years, Kaczynski had sent 16 mail bombs that left 23 people wounded or maimed and 3 people dead. In 1998, he pleaded guilty to the offenses and was sentenced to life in prison.
Ted Kaczynski, about age 15–16.©WBBM-TV/AFP/Getty Images
A decade before Kaczynski mailed his first bomb, Alice Walker spent her days battling racism in Mississippi. She had recently won her first writing fellowship, but rather than use the money to follow her dream of moving to Senegal, Africa, she put herself into the heart and heat of the civil rights movement. Walker had grown up knowing the brutal effects of poverty and racism. Born in 1944, she was the eighth child of Georgia sharecroppers who earned $300 a year. When Walker was 8, her brother accidentally shot her in the left eye with a BB gun. By the time her parents got her to the hospital a week later (they had no car), she was blind in that eye, and it had developed a disfiguring layer of scar tissue. Despite the counts against her, Walker overcame pain and anger and went on to win a Pulitzer Prize for her book The Color Purple. She became not only a novelist but also an essayist, a poet, a short-story writer, and a social activist.
Alice Walker won the Pulitzer Prize for her book The Color Purple. Like the characters in her book, Walker overcame pain and anger to triumph and celebrate the human spirit.©AP ImagesAlice Walker, about age 8.Courtesy of Alice Walker
Page 4
What leads one individual, so full of promise, to commit brutal acts of violence and another to turn poverty and trauma into a rich literary harvest? If you have ever wondered why people turn out the way they do, you have asked yourself the central question we will be exploring. This text traces the journey of human development—your own and that of every other member of the human species. In this chapter, we will explore what it means to take a life-span perspective on development, examine the nature of development, and outline how science helps us to understand it.
1 The Life-Span Perspective
LG1 Discuss the distinctive features of a life-span perspective on development.
The Importance of Studying Life-Span Development
Characteristics of the Life-Span Perspective
Some Contemporary Concerns
Each of us develops partly like all other individuals, partly like some other individuals, and partly like no other individual. Most of the time our attention is directed to each individual’s uniqueness. But as humans, we have all traveled some common paths. Each of us—Leonardo da Vinci, Joan of Arc, George Washington, Martin Luther King, Jr., and you—walked at about 1 year, engaged in fantasy play as a young child, and became more independent as a youth. Each of us, if we live long enough, will experience hearing problems and the death of family members and friends. This is the general course of our development, the pattern of movement or change that begins at conception and continues through the human life span.
We reach backward to our parents and forward to our children, and through their children to a future we will never see, but about which we need to care.
—Carl Jung
Swiss Psychiatrist, 20th Century
In this section, we will explore what is meant by the concept of development and why the study of life-span development is important. We will outline the main characteristics of the life-span perspective and discuss various sources of contextual influences. In addition, we will examine some contemporary concerns in life-span development.
How might people benefit from examining life-span development? Perhaps you are, or will be, a parent or teacher. If so, responsibility for children is, or will be, a part of your everyday life. The more you learn about them, the better you can deal with them. Perhaps you hope to gain some insight about your own history—as an infant, a child, an adolescent, or a young adult. Perhaps you want to know more about what your life will be like as you grow through the adult years—as a middle-aged adult, or as an adult in old age, for example. Or perhaps you just stumbled onto this course, thinking that it sounded intriguing and that the study of the human life span might raise some provocative issues. Whatever your reasons for taking this course, you will discover that the study of life-span development is intriguing and filled with information about who we are, how we came to be this way, and where our future will take us.
Most development involves growth, but it also includes decline (as in dying). In exploring development, we will examine the life span from the point of conception until the time when life (or at least life as we know it) ends. You will see yourself as an infant, as a child, and as an adolescent, and be stimulated to think about how those years influenced the kind of individual you are today. And you will see yourself as a young adult, as a middle-aged adult, and as an adult in old age, and be motivated to think about how your experiences today will influence your development through the remainder of your adult years.Page 5
Although growth and development are dramatic during the first two decades of life, development is not something that happens only to children and adolescents (Kennedy & Raz, 2015). The traditional approach to the study of development emphasizes extensive change from birth to adolescence (especially during infancy), little or no change in adulthood, and decline in old age. But a great deal of change does occur in the five or six decades after adolescence. The life-span approach emphasizes developmental change throughout adulthood as well as childhood (Park & Festini, 2018; Schaie & Willis, 2016).
Life Expectancy Recent increases in human life expectancy have contributed to the popularity of the life-span approach to development. The upper boundary of the human life span (based on the oldest age documented) is 122 years, as indicated in Figure 1; this maximum life span of humans has not changed since the beginning of recorded history. What has changed is life expectancy—the average number of years that a person born in a particular year can expect to live. In the twentieth century alone, life expectancy in the United States increased by 32 years, thanks to improvements in sanitation, nutrition, and medicine (see Figure 2). In 2016, the life expectancy in the United States was 79 years of age (U.S. Census Bureau, 2017). Today, for most individuals in developed countries, childhood and adolescence represent only about one-fourth of their lives.
FIGURE 1 MAXIMUM RECORDED LIFE SPAN FOR DIFFERENT SPECIES. Our only competitor for the maximum recorded life span is the Galápagos turtle.(Tortoise image on top) ©MedioImages/SuperStock; (mouse image at bottom) ©Redmond Durrell/AlamyFIGURE 2 HUMAN LIFE EXPECTANCY AT BIRTH FROM PREHISTORIC TO CONTEMPORARY TIMES. It took 5,000 years to extend human life expectancy from 18 to 41 years of age.
For the first time in U.S. history, there are more people over 60 years of age than under 15 years of age. In less than a century, more years were added to human life expectancy than in all of the prior millennia.
Laura Carstensen (2015, 2016) recently described the challenges and opportunities presented by this dramatic increase in life expectancy. In her view, the remarkable increase in the number of people living to an old age has happened so quickly that science, technology, and social expectations have not kept pace. She proposes that the challenge is to change from a world constructed mainly for young people to a world that is more compatible and supportive for the increasing number of people living to age 100 and beyond.
In further commentary, Carstensen (2015, p. 70) remarked that making this transformation would be no small feat:
. . . parks, transportation systems, staircases, and even hospitals presume that the users have both strength and stamina; suburbs across the country are built for two parents and their young children, not single people, multiple generations or elderly people who are not able to drive. Our education system serves the needs of young children and young adults and offers little more than recreation for experienced people.
Indeed, the very conception of work as a full-time endeavor ending in the early sixties is ill suited for long lives. Arguably the most troubling aspect of our view of aging is that we fret about ways the older people lack the qualities of younger people rather than exploit a growing new resource right before our eyes: citizens who have deep expertise, emotional balance, and the motivation to make a difference.
Certainly some progress has been made recently in improving the lives of older adults. In our discussion of late adulthood, you will read about progress in understanding and influencing the aging process through interventions such as modifying the activity of genes related to aging, improving brain function in the elderly, and slowing or even reversing the effects of various chronic diseases. You’ll also learn about ways to help people plan for a better life when they get old, become more cognitively sharp as they age, improve their physical fitness, and feel more satisfied with their lives as older adults. But much more remains to be accomplished, as suggested earlier by Laura Carstensen, as well as others (Bergeron, Ossenkoppele, & Laforce, 2018; Shrestha & others, 2018).
One-hundred-year-old Don Pellman from Santa Clara, California, keeps breaking world records in track for older adults, beating many contestants who are 20 and 30 years younger than he is.©Sandy Huffaker/The New York Times/Redux
The Life-Span Perspective The belief that development occurs throughout life is central to the life-span perspective on human development, but this perspective has other characteristics as well. According to life-span development expert Paul Baltes (1939–2006), the life-span perspective views development as lifelong, multidimensional, multidirectional, plastic, multidisciplinary, and contextual, and as a process that involves growth, maintenance, and regulation of loss (Baltes, 1987, 2003; Baltes, Lindenberger, & Staudinger, 2006). In Baltes’ Page 6view, it is important to understand that development is constructed through biological, sociocultural, and individual factors working together. Let’s explore each of these components of the life-span perspective.
Development Is Lifelong In the life-span perspective, early adulthood is not the endpoint of development; rather, no age period dominates development. Researchers increasingly study the experiences and psychological orientations of adults at different points in their lives. Later in this chapter, we will describe the age periods of development and their characteristics.
Development Is Multidimensional No matter what your age might be, your body, mind, emotions, and relationships are changing and affecting each other. Consider the development of Ted Kaczynski, the Unabomber discussed at the beginning of this chapter. When he was 6 months old, he was hospitalized with a severe allergic reaction and his parents were rarely allowed to visit him. According to his mother, the previously happy baby was never the same after his hospitalization. He became withdrawn and unresponsive. As Ted grew up, he had periodic “shutdowns” accompanied by rage. In his mother’s view, a biological event during infancy warped the development of her son’s mind and emotions.
Development has biological, cognitive, and socioemotional dimensions. Even within a dimension, there are many components (Dale & others, 2018; Moss & Wilson, 2018; Zammit & others, 2018). For example, attention, memory, abstract thinking, speed of processing information, and social intelligence are just a few of the components of the cognitive dimension.
Development Is Multidirectional Throughout life, some dimensions or components of a dimension expand and others shrink. For example, when one language (such as English) is acquired early in development, the capacity for acquiring second and third languages (such as Spanish and Chinese) decreases later in development, especially after early childhood (Levelt, 1989). During adolescence, as individuals establish romantic relationships, their time spent with friends may decrease. During late adulthood, older adults might become wiser because they have more experience than younger adults to draw upon to guide their decision making (Rakoczy & others, 2018; Thomas & others, 2018), but they perform more poorly on tasks that require speed in processing information (Salthouse, 2017).
Development Is Plastic Even at 10 years old, Ted Kaczynski was extraordinarily shy. Was he destined to remain forever uncomfortable with people? Developmentalists debate how much plasticity people have in various dimensions at different points in their development (Roisman & Cicchetti, 2017; Park & Festini, 2018). Plasticity means the capacity for change. For example, can you still improve your intellectual skills when you are in your seventies or eighties? Or might these intellectual skills be fixed by the time you are in your thirties so that further improvement is impossible? Researchers have found that the cognitive skills of older adults can be improved through training and acquisition of effective strategies (Motes & others, 2018; Shah & others, 2017). However, possibly we possess less capacity for change as we grow older (Shivarama Shetty & Sajikumar, 2017). Understanding plasticity and its constraints is a key element on the contemporary agenda for developmental research (Almy & Cicchetti, 2018; Park & Festini, 2018).
Paul Baltes, a leading architect of the life-span perspective of development, converses with one of the long-time research participants in the Berlin Aging Study that he directs. She joined the study in the early 1990s and has participated six times in extensive physical, medical, psychological, and social assessments. In her professional life, she was a physician.©Margaret M. and Paul B. Baltes Foundation
Developmental Science Is Multidisciplinary Psychologists, sociologists, anthropologists, neuroscientists, and medical researchers all share an interest in unlocking the mysteries of development through the life span. How do your heredity and health limit your intelligence? Do intelligence and social relationships change with age in the same ways around the world? How do families and schools influence intellectual development? These are examples of research questions that cut across disciplines.
Development Is Contextual All development occurs within a context, or setting. Contexts include families, schools, peer groups, churches, cities, neighborhoods, university laboratories, countries, and so on. Each of these settings is influenced by historical, economic, social, and cultural factors (Lubetkin & Jia, 2017; Nair, Roche, & White, 2018).
Contexts, like individuals, change (Taylor, Widaman, & Robins, 2018). Thus, individuals are changing beings in a changing world. As a result of these changes, contexts exert three types of influences (Baltes, 2003): (1) normative age-graded influences, (2) normative history-graded Page 7influences, and (3) nonnormative or highly individualized life events. Each type of influence can have a biological or environmental impact on development.
Normative age-graded influences are similar for individuals in a particular age group. These influences include biological processes such as puberty and menopause. They also include sociocultural factors and environmental processes such as beginning formal education (usually at about age 6 in most cultures) and retiring from the workforce (which takes place during the fifties and sixties in most cultures).
Normative history-graded influences are common to people of a particular generation because of historical circumstances (Ganguli, 2017; Heo & others, 2018). For example, during their youth American baby boomers shared the experience of the Cuban missile crisis, the assassination of John F. Kennedy, and the Beatles invasion. Other examples of normative history-graded influences include economic, political, and social upheavals such as the Great Depression in the 1930s, World War II in the 1940s, the civil rights and women’s rights movements of the 1960s and 1970s, the terrorist attacks of 9/11/2001, the integration of computers and cell phones into everyday life during the 1990s, and time spent on social media in the last decade (Schaie, 2016a, b; Tsai, Shillair, & Cotton, 2017). Long-term changes in the genetic and cultural makeup of a population (due to immigration or changes in fertility rates) are also part of normative historical change.
What characterizes the life-span perspective of development?©Derek E. Rothchild/Getty Images
Nonnormative life events are unusual occurrences that have a major impact on the lives of individual people. These events do not happen to everyone, and when they do occur they can influence people in different ways (Fredriksen-Goldsen & others, 2017; Jacobson & others, 2018; Shah & others, 2018). Examples include the death of a parent when a child is young, pregnancy in early adolescence, a fire that destroys a home, winning the lottery, or getting an unexpected career opportunity.
Nonnormative life events, such as Hurricane Sandy in 2012, are unusual circumstances that have a major impact on a person’s life.©Adam Hunger/Reuters/Landov
Development Involves Growth, Maintenance, and Regulation of Loss Baltes and his colleagues (2006) assert that the mastery of life often involves conflicts and competition among three goals of human development: growth, maintenance, and regulation of loss. As individuals age into middle and late adulthood, the maintenance and regulation of loss in their capacities takes center stage. Thus, a 75-year-old man might aim not to improve his memory or his golf swing but to maintain his independence and his ability to play golf at all. In the chapters on “Physical and Cognitive Development in Middle Adulthood” and “Socioemotional Development in Middle Adulthood” we will discuss these ideas about maintenance and regulation of loss in greater depth.
Development Is a Co-construction of Biology, Culture, and the Individual Development is a co-construction of biological, cultural, and individual factors working together (Baltes, Reuter-Lorenz, & Rösler, 2012). For example, the brain shapes culture, but it is also shaped by culture and the experiences that individuals have or pursue. In terms of individual factors, we can go beyond what our genetic inheritance and our environment give us. We can author a unique developmental path by actively choosing from the environment the things that optimize our lives (Rathunde & Csikszentmihalyi, 2006).
developmental connection
Middle Age
Adults typically face more losses in middle age than earlier in life. Connect to “Physical and Cognitive Development in Middle Adulthood.”
Pick up a newspaper or magazine and you might see headlines like these: “Technology Shortens Toddlers’ Attention Spans,” “Political Leanings May Be Written in the Genes,” “Mother Accused of Tossing Children into Bay,” “Transgender Bathroom Laws Face Controversy,” “FDA Warns About Long-Term Effects of ADHD Drug,” “Heart Attack Deaths Higher in African American Patients,” or “Test May Predict Alzheimer Disease.” Researchers using the life-span perspective are examining these and many other topics of contemporary concern. The roles that health and well-being, parenting, education, sociocultural contexts, and technology play in life-span development, as well as how social policy is related to these issues, are a particular focus of this edition.
developmental connection
What effect might exercise have on children’s and older adults’ ability to process information? Connect to “Physical and Cognitive Development in Middle and Late Childhood” and “Physical Development in Late Adulthood.”
Health and Well-Being Health professionals today recognize the powerful influences of lifestyles and psychological states on health and well-being (Hales, 2018; Rolfes, Pinna, & Whitney, 2018). In every chapter of Life-Span Development, issues of health and well-being are integrated into our discussions.
Clinical psychologists are among the health professionals who help people improve their well-being. Read about one clinical psychologist who helps adolescents and adults improve their developmental outcomes in Connecting with Careers.Page 8
connecting with careers
Gustavo Medrano, Clinical Psychologist
Gustavo Medrano specializes in helping children, adolescents, and adults of all ages improve their lives when they have problems involving depression, anxiety, emotion regulation, chronic health conditions, and life transitions. He works individually with clients and also provides therapy for couples and families. As a native Spanish speaker, he also provides bicultural and bilingual therapy for clients.
Gustavo Medrano, clinical psychologist, who does therapy with children, adolescents, and adults, especially using his bilingual background and skills to work with Latino clients.©Avis Mandel Pictures
Dr. Medrano is a faculty member at the Family Institute at Northwestern University in Evanston, Illinois. He obtained his undergraduate degree in psychology at Northwestern and then became a high school teacher through Teach for America, a program where participants spend at least two years teaching in a high-poverty area. He received his master’s and doctoral degrees in clinical psychology at the University of Wisconsin–Milwaukee. As a faculty member at Northwestern, in addition to doing clinical therapy with clients, he conducts research focusing on how family experiences, especially parenting, influence children’s and adolescents’ ability to cope with chronic pain and other challenges.
For more information about what clinical psychologists do, see the Careers in Life-Span Development appendix.
Parenting and Education Can two gay men raise a healthy family? Are children harmed if both parents work outside the home? Are U.S. schools failing to teach children how to read and write and calculate adequately? We hear many questions like these involving pressures on the contemporary family and conditions impairing the effectiveness of U.S. schools (Trejos-Castillo & Trevino-Schafer, 2018; Walsh, DeFlorio, & Burnham, 2017). In later chapters, we will analyze child care, the effects of divorce, parenting styles, child maltreatment, intergenerational relationships, early childhood education, links between childhood poverty and education, bilingual education, recent efforts to improve lifelong learning, and many other issues related to parenting and education (Gewirtz & Youssef, 2017; Morrison, 2018).
©Robert Maust/Photo Agora
Sociocultural Contexts and Diversity Health, parenting, and education—like development itself—are all shaped by their sociocultural context (Duncan, Magnuson, & Votruba-Drzal, 2017; Lansford & Banati, 2018). To analyze this context, four concepts are especially useful: culture, ethnicity, socioeconomic status, and gender.
Culture encompasses the behavior patterns, beliefs, and all other products of a particular group of people that are passed on from generation to generation (Kim & others, 2018). Culture results from the interaction of people over many years (Huo & Kim, 2018; Inglehart, 2018). A cultural group can be as large as the United States or as small as an isolated Appalachian town. Whatever its size, the group’s culture influences the behavior of its members (Erez, 2018; Matsumoto & Juang, 2017).Page 9
Cross-cultural studies compare aspects of two or more cultures. The comparison provides information about the degree to which development is similar (or universal) across cultures, or is instead culture-specific (Duell & others, 2018; Petersen & others, 2017; Wagner, 2018). For example, in a recent study of 26 countries, individuals in Chile had the highest life satisfaction, while those in Bulgaria and Spain had the lowest (Jang & others, 2017).
Ethnicity (the word ethnic comes from the Greek word for “nation”) is rooted in cultural heritage, nationality, race, religion, and language. African Americans, Latinos, Asian Americans, Native Americans, European Americans, and Arab Americans are a few examples of broad ethnic groups in the United States. Diversity exists within each ethnic group (Nieto & Bode, 2018; Suarez-Orozco, 2018a, b, c). A special concern is the discrimination and prejudice experienced by ethnic minority children (Brown, 2017; Motti-Stefanidi, 2018; Zeiders & others, 2018). Recent research indicates that pride in one’s ethnic identity group has positive outcomes (Umana-Taylor & Douglass, 2017; Umana-Taylor & others, 2018). For example, in a recent study, strong ethnic group affiliation and connection served a protective function in reducing risk for psychiatric problems (Anglin & others, 2018).
Asian American and Latino children are the fastest-growing immigrant groups in the United States. How diverse are the students in your life-span development class? How are their experiences in growing up likely similar to or different from yours?©Skip O’Rourke/Zuma Press Inc./Alamy
Socioeconomic status (SES) refers to a person’s position within society based on occupational, educational, and economic characteristics. Socioeconomic status implies certain inequalities (Duncan, Magnuson, & Votruba-Drzal, 2017; Loria & Caughy, 2018). Differences in the ability to control resources and to participate in society’s rewards produce unequal opportunities (Koller, Prates Santana, & Raffaelli, 2018; Singh & Mukherjee, 2018).
Gender refers to the characteristics of people as males and females. Few aspects of our development are more central to our identity and social relationships than gender (Dettori & Gupta, 2018; Ellemers, 2018; Liben, 2017).
Recently, considerable interest has been generated about a category of gender classification, transgender, a broad term that refers to individuals who adopt a gender identity that differs from the one assigned to them at birth (Budge & Orovecz, 2018; Savin-Williams, 2017). For example, individuals may have a female body but identify more strongly with being masculine than feminine, or have a male body but identify more strongly with being feminine than masculine. A transgender identity of being born male but identifying with being a female is much more common than the reverse (Zucker, Lawrence, & Kreukels, 2016). We will have much more to say about gender and transgender later in the text.
In the United States, the sociocultural context has become increasingly diverse in recent years. The U.S. population includes a greater variety of cultures and ethnic groups than ever before. This changing demographic tapestry promises not only the richness that diversity brings but also difficult challenges in extending the American dream to all individuals (Cano & others, 2017; Nieto & Bode, 2018). We will discuss sociocultural contexts and diversity in each chapter.
A special cross-cultural concern is the educational and psychological conditions of women around the world (UNICEF, 2017, 2018). Inadequate educational opportunities, violence, and mental health issues are among the problems faced by many women.
Considerable progress has been made in many parts of the world in girls’ school attendance (UNICEF, 2017). However, in some regions, girls continue to receive less education. For example, in secondary schools in West and Central Africa, only 76 girls are enrolled for every 100 boys (UNICEF, 2015).
Doly Akter, age 17, lives in a slum in Dhaka, Bangladesh, where sewers overflow, garbage rots in the streets, and children are undernourished. Nearly two-thirds of young women in Bangladesh marry before they are 18. Doly organized a club supported by UNICEF in which girls go door-to-door to monitor the hygiene habits of households in their neighborhood. The monitoring has led to improved hygiene and health in the families. Also, her group has managed to stop several child marriages by meeting with parents and convincing them that it is not in their daughter’s best interests. When talking with parents in their neighborhoods, the girls in the club emphasize the importance of staying in school and how this will improve their daughters’ future. Doly says that the girls in her UNICEF group are far more aware of their rights than their mothers ever were. (UNICEF, 2007).Courtesy of Naser Siddique/UNICEF Bangladesh
Social Policy Social policy is a government’s course of action designed to promote the welfare of its citizens. Values, economics, and politics all shape a nation’s social policy (Lansford & Banati, 2018; Ruck, Peterson-Badali, & Freeman, 2017). Out of concern that policy makers are doing too little to protect the well-being of children and older adults, life-span researchers are increasingly undertaking studies that they hope will lead to effective social policy (Lerner & others, 2018; McQueen, 2017).
Statistics such as infant mortality rates, mortality among children under 5, and the percentage of children who are malnourished or living in poverty provide benchmarks for evaluating how well children are doing in a particular society (UNICEF, 2017, 2018). Marian Wright Edelman, a tireless advocate for children’s rights, has pointed out that such indicators place the United States at or near the lowest rank for industrialized nations in the treatment of children.
Children who grow up in poverty represent a special concern (Duncan, Magnuson, & Votruba-Drzal, 2017; Suarez-Orozco, 2018a, b, c). In 2015, 19.7 percent of U.S. children under 18 years of age were living in families with incomes below the poverty line, with African American (36 percent) and Latino (30 percent) families with children having especially high rates of Page 10poverty (Jiang, Granja, & Koball, 2017). In 2015, 12 percent of non-Latino White children were living in poverty. Compared with non-Latino White children, ethnic minority children are more likely to experience persistent poverty over many years and live in isolated poor neighborhoods where social supports are minimal and threats to positive development are abundant.
Marian Wright Edelman, president of the Children’s Defense Fund (shown here advocating for health care), has been a tireless advocate of children’s rights and has been instrumental in calling attention to the needs of children. What are some of these needs?Courtesy of the Children’s Defense Fund and Marian Wright Edelman
The overall poverty rate for U.S. children did drop from 21.2 percent in 2014 to 19.7 percent in 2015 (Proctor, Semega, & Kollar, 2016). The 19.7 percent figure represents an increase from 2001 (14.5 percent) but reflects a slight drop from a peak of 23 percent in 1993.The U.S. figure of 19.7 percent of children living in poverty is much higher than the rates in other developed countries. For example, Canada has a child poverty rate of 9 percent and Sweden has a rate of 2 percent.
Ann Masten (far right) with a homeless mother and her child who are participating in her research on resilience. Masten and her colleagues have found that good parenting skills and good cognitive skills (especially attention and self-control) increase the likelihood that children in challenging circumstances will do well in elementary school.©Dawn Villella Photography
As indicated in Figure 3, one study found that a higher percentage of U.S. children in poor families than in middle-income families were exposed to family turmoil, separation from a parent, violence, crowding, excessive noise, and poor housing (Evans & English, 2002). One study also revealed that the more years children spent living in poverty, the higher were their physiological indices of stress (Evans & Kim, 2007).
FIGURE 3 EXPOSURE TO SIX STRESSORS AMONG POOR AND MIDDLE-INCOME CHILDREN. One study analyzed the exposure to six stressors among poor children and middle-income children (Evans & English, 2002). Poor children were much more likely to face each of these stressors.
Edelman says that parenting and nurturing the next generation of children is our society’s most important function and that we need to take it more seriously than we have in the past. To read about efforts to improve the lives of children through social policies, see Connecting Development to Life.
Some children triumph over poverty or other adversities. They show resilience (Masten, 2015, 2017). Think back to the chapter-opening story about Alice Walker. In spite of racism, poverty, low socioeconomic status, and a disfiguring eye injury, she went on to become a successful author and champion for equality.
Are there certain characteristics that make children like Alice Walker resilient? Are there other characteristics that influence the development of children like Ted Kaczynski, who, despite his intelligence and education, became a killer? After analyzing research on this topic, Ann Masten and her colleagues (Masten, 2006, 2009, 2011, 2013, 2014, 2015, 2016, 2017; Masten, Burt, & Coatsworth, 2006; Masten & Kalstabakken, 2018) concluded that a number of individual factors, such as good intellectual functioning, influence resiliency. In addition, as Figure 4 shows, the families and extrafamilial contexts of resilient individuals tend to share certain features. For example, resilient children are likely to have a close relationship with a caring parent figure and bonds to caring adults outside the family.
At the other end of the life span, the well-being of older adults also creates policy issues (Burns, Browning, and Kendig, 2017; Jennifer, 2018; Volkwein-Caplan & Tahmaseb-McConatha, 2018). Key concerns are escalating health care costs and the access of older adults to adequate health care (Cunningham, Green, & Braun, 2018; Kane, Saliba, & Hollmann, 2017). One study found that the U.S. health care system fails older adults in many areas (Wenger & others, 2003). For example, older adults received the recommended care for general medical conditions such as heart disease only 52 percent of the time; they received appropriate care for undernutrition and Alzheimer disease only 31 percent of the time.Page 11
connecting development to life
Improving Family Policy
In the United States, the actions of the national government, state governments, and city governments influence the well-being of children (Gottlieb & DeLoache, 2017; Lerner & others, 2018). When families seriously endanger a child’s well-being, governments often step in to help. At the national and state levels, policy makers have debated for decades about whether helping poor parents ends up helping their children as well. Researchers are providing some answers by examining the effects of specific policies (Duncan, Magnuson, & Vrtoba-Drzal, 2017).
For example, the Minnesota Family Investment Program (MFIP) was designed in the 1990s primarily to influence the behavior of adults—specifically, to move adults off the welfare rolls and into paid employment. A key element of the program was its guarantee that adults participating in the program would receive more income if they worked than if they did not. When the adults’ income rose, how did that affect their children? A study of the effects of MFIP found that increased incomes of working poor parents were linked with benefits for their children (Gennetian & Miller, 2002). The children’s achievement in school improved, and their behavior problems decreased. A current MFIP study is examining the influence of providing specific services to low-income families at risk for child maltreatment and other negative outcomes for children (Minnesota Family Investment Program, 2009).
There is increasing interest in developing two-generation educational interventions to improve the academic success of children living in poverty (Gardner, Brooks-Gunn, & Chase-Lansdale, 2016; Sommer & others, 2016). For example, a recent large-scale effort to help children escape from poverty is the Ascend two-generation education intervention being conducted by the Aspen Institute (2013, 2018; King, Chase-Lansdale, & Small, 2015). The focus of the intervention emphasizes education (increasing postsecondary education for mothers and improving the quality of their children’s early childhood education), economic support (housing, transportation, financial education, health insurance, and food assistance), and social capital (peer support including friends and neighbors; participation in community and faith-based organizations; school and work contacts).
Developmental psychologists and other researchers have examined the effects of many other government policies. They are seeking ways to help families living in poverty improve their well-being, and they have offered many suggestions for improving government policies (Lansford & Banati, 2018; McQueen, 2017; Motti-Stefanidi, 2018; Yoshikawa & others, 2017).
Earlier, we learned that children who live in poverty experience higher levels of physiological stress. How might a child’s stress level be affected by the implementation of MFIP?
These concerns about the well-being of older adults are heightened by two facts. First, the number of older adults in the United States is growing dramatically, as Figure 5 shows. Second, many of these older Americans are likely to need society’s help (Conway & others, 2018; Simon, Soni, & Cawley, 2017). Not only is the population of older adults growing in the United States, but the world’s population of people 60 years and older is projected to increase from 900 million in 2015 to 2.1 billion in 2050 (United Nations, 2015). The world’s population of those 80 years and older is expected to triple or quadruple in this time frame.
FIGURE 5 THE AGING OF AMERICA. The number of Americans over age 65 has grown dramatically since 1900 and is projected to increase further from the present to the year 2040. A significant increase will also occur in the number of individuals in the 85-and-over group. Centenarians—persons 100 years of age or older—are the fastest-growing age group in the United States, and their numbers are expected to swell in the coming decades.
Compared with adults in earlier decades, U.S. adults today are less likely to be married, more likely to be childless, and more likely to be living alone (Poey, Burr, & Roberts, 2017). As the older population continues to expand during the twenty-first century, an increasing number of older adults will be without either a spouse or children—traditionally the main sources of support for older adults. These individuals will need social relationships, networks, and other forms of support (Andrew & Meeks, 2018; Shankar & others, 2017).Page 12
Technology A final discussion in our exploration of contemporary topics is the recent dramatic, almost overwhelming increase in the use of technology at all points in human development (Lever-Duffy & McDonald, 2018; Vernon, Modecki, & Barber, 2018). From the introduction of television in the mid ’50s, to the replacement of typewriters with computers that can do far more than just print words, and later to the remarkable invention of the Internet and the proliferation of smartphones, followed by the pervasiveness of social media and the development of robots that can do some jobs better than humans can, our way of life has been changed permanently by technological advances.
How might the infusion of technology into children’s, adolescents’, and adults’ lives be changing the way they function and learn?©DaydreamsGirl/Getty Images
We will explore many technology topics in this edition. Later in this chapter you will read about the emerging field of developmental robotics in our discussion of information processing, and you will ponder the influence of technology on generations such as the millennials. Other topics we will explore include whether babies should watch television and videos, with special attention to potential effects of audiovisual media on language development; indications that too much screen time reduces children’s participation in physical activities and increases their risk for obesity and cardiovascular disease; the effects on learning when many adolescents spend more time using various media than they do in school and the question of whether multitasking with various electronic devices is harmful or beneficial; as well as the degree to which older adults are adapting to the extensive role of technology in their lives, especially since they grew up without so much technology.
Review Connect Reflect
LG1 Discuss the distinctive features of a life-span perspective on development.

What is meant by the concept of development? Why is the study of life-span development important?
What are the main characteristics of the life-span perspective? What are three sources of contextual influences?
What are some contemporary concerns in life-span development?


Give your own example (not found in this chapter) of how biology, culture, and individual experience interact to affect development.

Reflect Your Own Personal Journey of Life

Imagine what your development would have been like in a culture that offered fewer or distinctly different choices. How might your development have been different if your family had been significantly richer or poorer?

Page 13
2 The Nature of Development
LG2 Identify the most important processes, periods, and issues in development.
Biological, Cognitive, and Socioemotional Processes
Periods of Development
The Significance of Age
Developmental Issues
In this section, we will explore what is meant by developmental processes and periods, as well as variations in the way age is conceptualized. We will examine key developmental issues and strategies we can use to evaluate them.
If you wanted to describe how and why Alice Walker or Ted Kaczynski developed during their lifetimes, how would you go about it? A chronicle of the events in any person’s life can quickly become a confusing and tedious array of details. Two concepts help provide a framework for describing and understanding an individual’s development: developmental processes and periods.
At the beginning of this chapter, we defined development as the pattern of change that begins at conception and continues through the life span. The pattern is complex because it is the product of biological, cognitive, and socioemotional processes (see Figure 6).
FIGURE 6 PROCESSES INVOLVED IN DEVELOPMENTAL CHANGES. Biological, cognitive, and socioemotional processes interact as individuals develop.
Biological Processes Biological processes produce changes in an individual’s physical nature. Genes inherited from parents, brain development, height and weight gains, changes in motor skills, nutrition, exercise, the hormonal changes of puberty, and cardiovascular decline are all examples of biological processes that affect development. Especially in recent years with the advent of new techniques to study people’s actual genetic makeup, there has been a substantial increase in studies that focus on the role of genes in development at different points in the life span (Amare & others, 2017; Bardak & others, 2018). Likewise, with the invention of brain-imaging techniques such as magnetic resonance imaging, there has been an explosion of research on how the brain influences many aspects of development at different points in the life span (Bell & others, 2018; Park & Festini, 2018).
Cognitive Processes Cognitive processes refer to changes in the individual’s thought, intelligence, and language. Watching a colorful mobile swinging above the crib, putting together a two-word sentence, memorizing a poem, imagining what it would be like to be a movie star, and solving a crossword puzzle all involve cognitive processes.
Socioemotional Processes Socioemotional processes involve changes in the individual’s relationships with other people, changes in emotions, and changes in personality. An infant’s smile in response to a parent’s touch, a toddler’s aggressive attack on a playmate, a school-age child’s development of assertiveness, an adolescent’s joy at the senior prom, and the affection of an elderly couple all reflect the role of socioemotional processes in development.
developmental connection
Brain Development
Is there a link between changes in the adolescent’s brain and their mood swings and increased risk taking? Connect to “Physical and Cognitive Development in Adolescence.”
Connecting Biological, Cognitive, and Socioemotional Processes Biological, cognitive, and socioemotional processes are inextricably intertwined (Diamond, 2013). Consider a baby smiling in response to a parent’s touch. This response depends on biological processes (the physical nature of touch and responsiveness to it), cognitive processes (the ability to understand intentional acts), and socioemotional processes (the fact that smiling often reflects a positive emotional feeling and helps to connect us in positive ways with other human beings). Nowhere is the connection across biological, cognitive, and socioemotional processes more obvious than in two rapidly emerging fields:

developmental cognitive neuroscience, which explores links between development, cognitive processes, and the brain (Bell & others, 2018; Nyberg, Pudas, & Lundquist, 2017).
developmental social neuroscience, which examines connections between socioemotional processes, development, and the brain (Silvers & others, 2017; Sullivan & Wilson, 2018).

Page 14In many instances, biological, cognitive, and socioemotional processes are bidirectional. For example, biological processes can influence cognitive processes and vice versa. Thus, although usually we will study the different processes of development (biological, cognitive, and socioemotional) separately, keep in mind that we are talking about the development of an integrated individual with a mind and body that are interdependent. In many places throughout the book, we will call attention to these connections.
The interplay of biological, cognitive, and socioemotional processes produces the periods of the human life span (see Figure 7). A developmental period refers to a time frame in a person’s life that is characterized by certain features. For the purposes of organization and understanding, we commonly describe development in terms of these periods. The most widely used classification of developmental periods involves the eight-period sequence shown in Figure 7. Approximate age ranges are listed for the periods to provide a general idea of when each period begins and ends.
FIGURE 7 PROCESSES AND PERIODS OF DEVELOPMENT. The unfolding of life’s periods of development is influenced by the interaction of biological, cognitive, and socioemotional processes.(Photo credit left to right) ©Brand X Pictures/PunchStock; Courtesy of Dr. John Santrock; ©Laurence Mouton/Photoalto/PictureQuest; ©Digital Vision/Getty Images; ©SW Productions/Getty Images; ©Blue Moon Stock/Alamy Images; ©Sam Edwards/Glow Images; ©Ronnie Kaufman/Blend Images LLC
The prenatal period is the time from conception to birth. It involves tremendous growth—from a single cell to an organism complete with brain and behavioral capabilities—and takes place in approximately a 9-month period.
Infancy is the developmental period from birth to 18 or 24 months. Infancy is a time of extreme dependence upon adults. During this period, many psychological activities—language, symbolic thought, sensorimotor coordination, and social learning, for example—are just beginning.
The term toddler is often used to describe a child from about 1 ½ to 3 years of age. Toddlers are in a transitional period between infancy and the next period, early childhood.
Early childhood is the developmental period from 3 through 5 years of age. This period is sometimes called the “preschool years.” During this time, young children learn to become more self-sufficient and to care for themselves, develop school readiness skills (following instructions, identifying letters), and spend many hours playing with peers. First grade typically marks the end of early childhood.
Middle and late childhood is the developmental period from about 6 to 10 or 11 years of age, approximately corresponding to the elementary school years. During this period, children Page 15master the fundamental skills of reading, writing, and arithmetic, and they are formally exposed to the larger world and its culture. Achievement becomes a more central theme of the child’s world, and self-control increases.
Adolescence is the developmental period of transition from childhood to early adulthood, entered at approximately 10 to 12 years of age and ending at 18 to 21 years of age. Adolescence begins with rapid physical changes—dramatic gains in height and weight, changes in body contour, and the development of sexual characteristics such as enlargement of the breasts, growth of pubic and facial hair, and deepening of the voice. At this point in development, the pursuit of independence and an identity are preeminent. Thought is more logical, abstract, and idealistic. More time is spent outside the family.
There has been a substantial increase in interest in the transition between adolescence and early adulthood, a transition that can be a long one as individuals develop more effective skills to become full members of society. Recently, the transition from adolescence to adulthood has been referred to as emerging adulthood, the period from approximately 18 to 25 years of age (Arnett, 2015, 2016a, b). Experimentation and exploration characterize the emerging adult. At this point in their development, many individuals are still exploring which career path they want to follow, what they want their identity to be, and which lifestyle they want to adopt (for example, single, cohabiting, or married) (Jensen, 2018; Padilla-Walker & Nelson, 2017).
Early adulthood is the developmental period that begins in the early twenties and lasts through the thirties. It is a time of establishing personal and economic independence, advancing in a career, and for many, selecting a mate, learning to live with that person in an intimate way, starting a family, and rearing children.
Middle adulthood is the developmental period from approximately 40 to about 60 years of age. It is a time of expanding personal and social involvement and responsibility; of assisting the next generation in becoming competent, mature individuals; and of reaching and maintaining satisfaction in a career.
Late adulthood is the developmental period that begins during the sixties or seventies and lasts until death. It is a time of life review, retirement, and adjustment to new social roles and diminishing strength and health.
One’s children’s children’s children. Look back to us as we look to you; we are related by our imaginations. If we are able to touch, it is because we have imagined each other’s existence, our dreams running back and forth along a cable from age to age.
—Roger Rosenblatt
Contemporary American Writer
Late adulthood has the longest span of any period of development, and as noted earlier, the number of people in this age group has been increasing dramatically. As a result, life-span developmentalists have been paying more attention to late adulthood (Bangerter & others, 2018; Frankenmolen & others, 2018; Orkaby & others, 2018). Paul Baltes and Jacqui Smith (2003) argue that a major change takes place in older adults’ lives as they become the “oldest-old,” on average at about 85 years of age. For example, the “young-old” (classified as 65 through 84 in this analysis) have substantial potential for physical and cognitive fitness, retain much of their cognitive capacity, and can develop strategies to cope with the gains and losses of aging. In contrast, the oldest-old (85 and older) show considerable loss in cognitive skills, experience an increase in chronic stress, and become more frail.
Thus, Baltes and Smith concluded that considerable plasticity and adaptability characterize adults from their sixties until their mid-eighties but that the oldest-old have reached the limits of their functional capacity, which makes interventions to improve their lives difficult. Nonetheless, as will be described in later chapters, considerable variation exists in the degree to which the oldest-old retain their capabilities (Mejia & others, 2017).
Four Ages Life-span developmentalists who focus on adult development and aging increasingly describe life-span development in terms of four “ages” (Baltes, 2006; Willis & Schaie, 2006):

First age: Childhood and adolescence
Second age: Prime adulthood, ages 20 through 59
Third age: Approximately 60 to 79 years of age
Fourth age: Approximately 80 years and older

The major emphasis in this conceptualization is on the third and fourth ages, especially the increasing evidence that individuals in the third age are healthier and can lead more active, productive lives than their predecessors in earlier generations. However, when older adults reach their eighties (fourth age), especially 85 and over, health and well-being decline for many individuals.Page 16
Three Developmental Patterns of Aging K. Warner Schaie (2016a, b) recently described three different developmental patterns that provide a portrait of how aging can encompass individual variations:

Normal aging characterizes most individuals, for whom psychological functioning often peaks in early middle age, remains relatively stable until the late fifties to early sixties, and then shows a modest decline through the early eighties. However, marked decline can occur as individuals approach death.
Pathological aging characterizes individuals who show greater than average decline as they age through the adult years. In early old age, they may have mild cognitive impairment, develop Alzheimer disease later on, or have a chronic disease that impairs their daily functioning.
Successful aging characterizes individuals whose positive physical, cognitive, and socioemotional development is maintained longer, declining later in old age than is the case for most people. For too long, only the declines that occur in late adulthood were highlighted, but recently there has been increased interest in the concept of successful aging (Docking & Stock, 2018).

Connections Across Periods of Development A final important point needs to be made about the periods of the human life span. Just as there are many connections between biological, cognitive, and socioemotional processes, so are there many connections between the periods of the human life span. A key element in the study of life-span development is how development in one period is connected to development in another period. For example, when individuals reach adolescence, many developments and experiences have already taken place in their lives. If an adolescent girl becomes depressed, might her depression be linked to development early in her life, as well as recent and current development? Throughout the text we will call attention to such connections across periods of development through Developmental Connection inserts that guide you to earlier or later connections with the material you are currently reading.
In our description of developmental periods, we linked an approximate age range with each period. But we also have noted that there are variations in the capabilities of individuals of the same age, and we have seen how age-related changes can be exaggerated. How important is age in understanding the characteristics of an individual?
Age and Happiness Is there a best age to be? An increasing number of studies indicate that in the United States adults are happier as they age. Consider also a U.S. study of approximately 28,000 individuals from 18 to 88 that revealed happiness increased with age (Yang, 2008). About 33 percent were very happy at 88 years of age compared with only about 24 percent in their late teens and early twenties. Why might older people report being happier and more satisfied with their lives than younger people? Despite facing higher incidences of physical problems and losses, older adults are more content with what they have in their lives, have better relationships with the people who matter to them, are less pressured to achieve, have more time for leisurely pursuits, and have many years of experience resulting in wisdom that may help them adapt better to their circumstances than younger adults do (Carstensen, 2015; Sims, Hogan, & Carstensen, 2015). Researchers have also found that baby boomers (those born between 1946 and 1964) tend to report being less happy than individuals born earlier—possibly because they are not lowering their aspirations and idealistic hopes as they age, as did earlier generations. Because growing older is a certain outcome of staying alive, it is good to know that we are likely to be happier as older adults than we were when we were younger.
Which of these individuals is likely to be the happiest and to report the highest level of psychological well-being?©Jetta Productions/Blend Images/Getty Images
Page 17Not all studies, though, have found an increase in life satisfaction with age (Steptoe, Deaton, & Stone, 2015). Some studies indicate that the lowest levels of life satisfaction occur in middle age, especially from 45 to 54 years of age (OECD, 2014). Other studies have found that life satisfaction varies across some countries. For example, respondents in research studies conducted in the former Soviet Union and Eastern Europe, as well as in South American countries, reported a decrease in life satisfaction with advancing age (Deaton, 2008). Further, older adults in poor health, such as those with cardiovascular disease, chronic lung disease, and depression, tend to be less satisfied with their lives than their healthier older adult counterparts (Lamont & others, 2017).
Now that you have read about age variations in life satisfaction, think about how satisfied you are with your life. To help you answer this question, complete the items in Figure 8, which presents the most widely used measure in research on life satisfaction (Diener, 2018).
FIGURE 8 HOW SATISFIED AM I WITH MY LIFE?Source: E. Diener, R. A. Emmons, R. J. Larson, & S. Griffin. “The Satisfaction with Life Scale.” Journal of Personality Assessment, 48, 1985, 71–75.
Conceptions of Age According to some life-span experts, chronological age is not very relevant to understanding a person’s psychological development (Botwinick, 1978). Chronological age is the number of years that have elapsed since birth. But time is a crude index of experience, and it does not cause anything. Chronological age, moreover, is not the only way to measure age (MacDonald & Stawski, 2016). Just as there are different domains of development, there are different ways of thinking about age.
Age has been conceptualized not just as chronological age but also as biological age, psychological age, and social age (Hoyer & Roodin, 2009). Biological age is a person’s age in terms of biological health. Determining biological age involves knowing the functional capacities of a person’s vital organs. One person’s vital capacities may be better or worse than those of other people of comparable age (Richards & others, 2015). A recent study of 17-year survival rates in Korean adults 20 to 93 years of age found that when biological age was greater than chronological age individuals were less likely to have died (Yoo & others, 2017). The younger the person’s biological age, the longer the person is expected to live, regardless of chronological age.
(Left): Seventy-four year old Barbara Jordan participating in the long jump competition at a Senior Games in Maine; (right): a sedentary overweight middle-aged man. Even though Barbara Jordan’s chronological age is older, might her biological age be younger than the middle-aged man’s?(left) ©John Patriquin/Portland Press Herald/Getty Images; (right) ©Owaki-Kulla/Corbis/Getty Images
Page 18Psychological age is an individual’s adaptive capacities compared with those of other individuals of the same chronological age. Thus, older adults who continue to learn, are flexible, are motivated, have positive personality traits, control their emotions, and think clearly are engaging in more adaptive behaviors than their chronological age-mates who do not continue to learn, are rigid, are unmotivated, do not control their emotions, and do not think clearly (Rakoczy & others, 2018; Thomas & others, 2018). A longitudinal study of more than 1,200 individuals across seven decades revealed that the personality trait of conscientiousness (being organized, careful, and disciplined, for example) predicted lower mortality (frequency of death) risk from childhood through late adulthood (Martin, Friedman, & Schwartz, 2007). And a recent study found that a higher level of conscientiousness was protective of cognitive functioning in older adults (Wilson & others, 2015).
How old would you be if you didn’t know how old you were?
—Satchel Paige
American Baseball Pitcher, 20th Century
Social age refers to connectedness with others and the social roles individuals adopt. Individuals who have better social relationships with others are happier and more likely to live longer than individuals who are lonely (Carstensen & others, 2015; Reed & Carstensen, 2015).
Life-span expert Bernice Neugarten (1988) argues that in U.S. society chronological age is becoming irrelevant. The 28-year-old mayor, the 35-year-old grandmother, the 65-year-old father of a preschooler, the 55-year-old widow who starts a business, and the 70-year-old student illustrate that old assumptions about the proper timing of life events no longer govern our lives. We still have some expectations for when certain life events—such as getting married, having children, and retiring—should occur. However, chronological age has become a less accurate predictor of these life events in our society. Moreover, issues such as how to deal with intimacy and how to cope with success and failure appear and reappear throughout the life span.
From a life-span perspective, an overall age profile of an individual involves not just chronological age but also biological age, psychological age, and social age. For example, a 70-year-old man (chronological age) might be in good physical health (biological age), be experiencing memory problems and not be coping well with the demands placed on him by his wife’s recent hospitalization (psychological age), and have a number of friends with whom he regularly plays golf (social age).
developmental connection
Nature and Nurture
Can specific genes be linked to specific environmental experiences to influence development? Connect to “Biological Beginnings.”
Was Ted Kaczynski born a killer, or did his life turn him into one? Kaczynski himself thought that his childhood was the root of his troubles, saying that he grew up as a genius in a boy’s body and never fit in with other children. Did his early experiences determine his later life? Is your own journey through life marked out ahead of time, or can your experiences change your path? Are the experiences you have early in your journey more important than later ones? Is your journey more like taking an elevator up a skyscraper with distinct stops along the way or more like a cruise down a river with smoother ebbs and flows? These questions point to three issues about the nature of development: the roles played by nature and nurture, stability and change, and continuity and discontinuity.
developmental connection
How much does personality change as people go through the adult years? Connect to “Socioemotional Development in Middle Adulthood.”
What are some key developmental issues?©Rubberball/PictureQuest
Nature and Nurture The nature-nurture issue involves the extent to which development is influenced by nature and by nurture. Nature refers to an organism’s biological inheritance, nurture to its environmental experiences.
According to those who emphasize the role of nature, just as a sunflower grows in an orderly way—unless flattened by an unfriendly environment—so too the human grows in an orderly way. An evolutionary and genetic foundation produces commonalities in growth and development (Freedman, 2017; Starr, Evers, & Starr, 2018). We walk before we talk, speak one word before two words, grow rapidly in infancy and less so in early childhood, experience a rush of sex hormones in puberty, reach the peak of our physical strength in late adolescence and early adulthood, and then physically decline. Proponents of the importance of nature acknowledge that extreme environments—those that are psychologically barren or hostile—can depress development. However, they believe that basic growth tendencies are genetically programmed into humans (Johnson, 2017).
By contrast, other psychologists emphasize the importance of nurture, or environmental experiences, in development (Almy & Cicchetti, 2018; Nicolaisen & Thorsen, 2017; Rubin & Barstead, 2018). Experiences run the gamut from the individual’s biological environment Page 19(nutrition, medical care, drugs, and physical accidents) to the social environment (family, peers, schools, community, media, and culture).
There has been a dramatic increase in the number of studies that reflect the epigenetic view, which states that development reflects an ongoing, bidirectional interchange between genes and the environment. These studies involve specific DNA sequences (Bakusic & others, 2017; Halldorsdottir & Binder, 2017). The epigenetic mechanisms involve the actual molecular modification of the DNA strand as a result of environmental inputs in ways that alter gene functioning (Moore, 2017; Clukay & others, 2018; Marzi & others, 2018). In “Biological Beginnings” we will explore the epigenetic approach in greater depth.
Stability and Change Is the shy child who hides behind the sofa when visitors arrive destined to become a wallflower at college dances, or might the child become a sociable, talkative individual? Is the fun-loving, carefree adolescent bound to have difficulty holding down a 9-to-5 job as an adult? These questions reflect the stability-change issue, which involves the degree to which early traits and characteristics persist through life or change.
Many developmentalists who emphasize stability in development argue that stability is the result of heredity and possibly early experiences in life. For example, many argue that if an individual is shy throughout life (as Ted Kaczynski was), this stability is due to heredity and possibly early experiences in which the infant or young child encountered considerable stress when interacting with people.
Developmentalists who emphasize change take the more optimistic view that later experiences can produce change. Recall that in the life-span perspective, plasticity, the potential for change, exists throughout the life span, although possibly to different degrees (Park & Festini, 2018; Motes & others, 2018). Experts such as Paul Baltes (2003) argue that older adults often show less capacity for learning new things than younger adults do. However, many older adults continue to be good at practicing what they have learned earlier in life.
The roles of early and later experience are an aspect of the stability-change issue that has long been hotly debated (Chen & others, 2018; Roisman & Cicchetti, 2017). Some argue that warm, nurturant caregiving during infancy and toddlerhood predicts optimal development later in life (Cassidy, 2016). The later-experience advocates see children as malleable throughout development and believe later sensitive caregiving is just as important as earlier sensitive caregiving (Joling & others, 2018; Taylor & others, 2018).
Continuity and Discontinuity When developmental change occurs, is it gradual or abrupt? Think about your own development for a moment. Did you gradually become the person you are today? Or did you experience sudden, distinct changes as you matured? For the most part, developmentalists who emphasize nurture describe development as a gradual, continuous process. Those who emphasize nature often describe development as a series of distinct stages.
The continuity-discontinuity issue focuses on the degree to which development involves either gradual, cumulative change (continuity) or distinct stages (discontinuity). In terms of continuity, as the oak grows from seedling to giant oak, it becomes more of an oak—its development is continuous (see Figure 9). Similarly, a child’s first word, though seemingly an abrupt, discontinuous event, is actually the result of weeks and months of growth and practice. Puberty might seem abrupt, but it is a gradual process that occurs over several years.
FIGURE 9 CONTINUITY AND DISCONTINUITY IN DEVELOPMENT. Is our development like that of a seedling gradually growing into a giant oak? Or is it more like that of a caterpillar suddenly becoming a butterfly?
In terms of discontinuity, as an insect grows from a caterpillar to a chrysalis to a butterfly, it passes through a sequence of stages in which change is qualitatively rather than quantitatively different. Similarly, at some point a child moves from not being able to think abstractly about the world to being able to do so. This is a qualitative, discontinuous change in development rather than a quantitative, continuous change.
Evaluating the Developmental Issues Most life-span developmentalists acknowledge that development is not all nature or all nurture, not all stability or all change, and not all continuity or all discontinuity. Nature and nurture, stability and change, continuity and discontinuity characterize development throughout the human life span.
Although most developmentalists do not take extreme positions on these three important issues, there is spirited debate regarding how strongly development is influenced by each of these factors (Almy & Cicchetti, 2018; Moore, 2017).
Page 20
Review Connect Reflect
LG2 Identify the most important processes, periods, and issues in development.

What are three key developmental processes?
What are eight main developmental periods?
How is age related to development?
What are three main developmental issues?


In the previous section, we discussed biological, cognitive, and socioemotional processes. What concepts do these processes have in common with the issue of nature versus nurture, which was also discussed in this section?

Reflect Your Own Personal Journey of Life

Do you think there was/is/will be a best age for you to be? If so, what is it? Why?

3 Theories of Development
LG3 Describe the main theories of human development.
Psychoanalytic Theories
Cognitive Theories
Behavioral and Social Cognitive Theories
Ethological Theory
Ecological Theory
An Eclectic Theoretical Orientation
How can we answer questions about the roles of nature and nurture, stability and change, and continuity and discontinuity in development? How can we determine, for example, whether deterioration of memory in older adults can be prevented or whether special care can repair the harm inflicted by child neglect? The scientific method is the best tool we have to answer such questions (Smith & Davis, 2016).
There is nothing quite so practical as a good theory.
—Kurt Lewin
American Social Psychologist, 20th Century
The scientific method is essentially a four-step process: (1) conceptualize a process or problem to be studied, (2) collect research information (data), (3) analyze the data, and (4) draw conclusions.
In step 1, when researchers are formulating a problem to study, they often draw on theories and develop hypotheses. A theory is an interrelated, coherent set of ideas that helps to explain phenomena and facilitate predictions. It may suggest hypotheses, which are specific assertions and predictions that can be tested. For example, a theory on mentoring might state that sustained support and guidance from an adult makes a difference in the lives of children from impoverished backgrounds because the mentor gives the children opportunities to observe and imitate the behavior and strategies of the mentor.
This section outlines key aspects of five theoretical orientations to development: psychoanalytic, cognitive, behavioral and social cognitive, ethological, and ecological. Each contributes an important piece to the life-span development puzzle. Although the theories disagree about certain aspects of development, many of their ideas are complementary rather than contradictory. Together they let us see the total landscape of life-span development in all its richness.
Psychoanalytic theories describe development as primarily unconscious (beyond awareness) and heavily colored by emotion. Psychoanalytic theorists emphasize that behavior is merely a surface characteristic and that a true understanding of development requires analyzing the symbolic meanings of behavior and the deep inner workings of the mind. Psychoanalytic theorists also stress that early experiences with parents extensively shape development. These characteristics are highlighted in the main psychoanalytic theory, that of Sigmund Freud (1856–1939).
Freud’s Theory As Freud listened to, probed, and analyzed his patients, he became convinced that their problems were the result of experiences early in life. He thought that as children grow up, their focus of pleasure and sexual impulsesPage 21 shifts from the mouth to the anus and eventually to the genitals. As a result, we go through five stages of psychosexual development: oral, anal, phallic, latency, and genital (see Figure 10). Our adult personality, Freud (1917) claimed, is determined by the way we resolve conflicts between sources of pleasure at each stage and the demands of reality.
FIGURE 10 FREUDIAN STAGES. Because Freud emphasized sexual motivation, his stages of development are known as psychosexual stages. In his view, if the need for pleasure at any stage is either undergratified or overgratified, an individual may become fixated, or locked in, at that stage of development.
Freud’s theory has been significantly revised by a number of psychoanalytic theorists. Many of today’s psychoanalytic theorists maintain that Freud overemphasized sexual instincts; they argue that more emphasis should be placed on cultural experiences as determinants of an individual’s development. Unconscious thought remains a central theme, but conscious thought plays a greater role than Freud envisioned. One of the most influential revisionists of Freud’s ideas was Erik Erikson.
Sigmund Freud, the pioneering architect of psychoanalytic theory. How did Freud portray the organization of an individual’s personality?©Bettmann/Getty Images
Erikson’s Psychosocial Theory Erik Erikson (1902–1994) recognized Freud’s contributions but believed that Freud misjudged some important dimensions of human development. For one thing, Erikson (1950, 1968) said we develop in psychosocial stages, rather than in psychosexual stages as Freud maintained. According to Freud, the primary motivation for human behavior is sexual in nature; according to Erikson, it is social and reflects a desire to affiliate with other people. According to Freud, our basic personality is shaped during the first five years of life; according to Erikson, developmental change occurs throughout the life span. Thus, in terms of the early-versus-later-experience issue described earlier in the chapter, Freud viewed early experience as being far more important than later experiences, whereas Erikson emphasized the importance of both early and later experiences.
In Erikson’s theory, eight stages of development unfold as we go through life (see Figure 11). At each stage, a unique developmental task confronts individuals with a crisis that must be resolved. According to Erikson, this crisis is not a catastrophe but a turning point marked by both increased vulnerability and enhanced potential. The more successfully an individual resolves each crisis, the healthier development will be.
FIGURE 11 ERIKSON’S EIGHT LIFE-SPAN STAGES. Like Freud, Erikson proposed that individuals go through distinct, universal stages of development. Thus, in terms of the continuity-discontinuity issue discussed in this chapter, both favor the discontinuity side of the debate. Notice that the timing of Erikson’s first four stages is similar to that of Freud’s stages. What are the implications of saying that people go through stages of development?
Trust versus mistrust is Erikson’s first psychosocial stage, which is experienced in the first year of life. The development of trust during infancy sets the stage for a lifelong expectation that the world will be a good and pleasant place to live.
Autonomy versus shame and doubt is Erikson’s second stage. This stage occurs in late infancy and toddlerhood (1 to 3 years). After gaining trust in their caregivers, infants begin to discover that their behavior is their own. They start to assert their sense of independence or autonomy. They realize their will. If infants and toddlers are restrained too much or punished too harshly, they are likely to develop a sense of shame and doubt.
Erik Erikson with his wife, Joan, an artist. Erikson generated one of the most important developmental theories of the twentieth century. Which stage of Erikson’s theory are you in? Does Erikson’s description of this stage characterize you?©Jon Erikson/The Image Works
Initiative versus guilt, Erikson’s third stage of development, occurs during the preschool years. As preschool children encounter a widening social world, they face new challenges that require active, purposeful, responsible behavior. Feelings of guilt may arise, though, if the child is irresponsible and is made to feel too anxious.
Industry versus inferiority is Erikson’s fourth developmental stage, occurring approximately during the elementary school years. Children now need to direct their energy toward mastering knowledge and intellectual skills. The negative outcome is that the child may developPage 22 a sense of inferiority—feeling incompetent and unproductive.
During the adolescent years, individuals need to find out who they are, what they are all about, and where they are going in life. This is Erikson’s fifth developmental stage, identity versus identity confusion. If adolescents explore roles in a healthy manner and arrive at a positive path to follow in life, then they achieve a positive identity; if they do not, identity confusion reigns.
Intimacy versus isolation is Erikson’s sixth developmental stage, which individuals experience during early adulthood. At this time, individuals face the developmental task of forming intimate relationships. If young adults form healthy friendships and an intimate relationship with another, intimacy will be achieved; if not, isolation will result.
Generativity versus stagnation, Erikson’s seventh developmental stage, occurs during middle adulthood. By generativity Erikson means primarily a concern for helping the younger generation to develop and lead useful lives. The feeling of having done nothing to help the next generation is stagnation.
Integrity versus despair is Erikson’s eighth and final stage of development, which individuals experience in late adulthood. During this stage, a person reflects on the past. If the person’s life review reveals a life well spent, integrity will be achieved; if not, the retrospective glances likely will yield doubt or gloom—the despair Erikson described.
Jean Piaget, the famous Swiss developmental psychologist, changed the way we think about the development of children’s minds. What are some key ideas in Piaget’s theory?©Yves de Braine/Black Star/Stock Photo
Evaluating Psychoanalytic Theories Contributions of psychoanalytic theories include an emphasis on a developmental framework, family relationships, and unconscious aspects of the mind. Criticisms include a lack of scientific support, too much emphasis on sexual underpinnings, and an image of people that is too negative.
Whereas psychoanalytic theories stress the importance of the unconscious, cognitive theories emphasize conscious thoughts. Three important cognitive theories are Jean Piaget’s cognitive developmental theory, Lev Vygotsky’s sociocultural cognitive theory, and the information-processing theory.
Piaget’s Cognitive Developmental Theory Piaget’s theory states that children go through four stages of cognitive development as they actively construct their understanding of the world. Two processes underlie this cognitive construction of the world: organization and adaptation. To make sense of our world, we organize our experiences. For example, we separate important ideas from less important ideas, and we connect one idea to another. In addition to organizing our observations and experiences, we adapt, adjusting to new environmental demands (Miller, 2015).
Piaget (1954) identified four stages in understanding the world (see Figure 12). Each stage is age-related and consists of a distinct way of thinking, a different way of understanding the world. Thus, according to Piaget (1896–1980), the child’s cognition is qualitatively different from one stage to another. What are Piaget’s four stages of cognitive development?
FIGURE 12 Piaget’s Four Stages of Cognitive Development. According to Piaget, how a child thinks—not how much the child knows—determines the child’s stage of cognitive development.(Photo credit left to right) ©Stockbyte/Getty Images; ©BananaStock/PunchStock; ©image100/Corbis; ©Purestock/Getty Images

The sensorimotor stage, which lasts from birth to about 2 years of age, is the first Piagetian stage. In this stage, infants construct an understanding of the world by coordinating sensory experiences (such as seeing and hearing) with physical, motoric actions—hence the term sensorimotor.
The preoperational stage, which lasts from approximatelyPage 23 2 to 7 years of age, is Piaget’s second stage. In this stage, children begin to go beyond simply connecting sensory information with physical action and represent the world with words, images, and drawings. However, according to Piaget, preschool children still lack the ability to perform what he calls operations, which are internalized mental actions that allow children to do mentally what they previously could only do physically. For example, if you imagine putting two sticks together to see whether they would be as long as another stick, without actually moving the sticks, you are performing a concrete operation.
The concrete operational stage, which lasts from approximately 7 to 11 years of age, is the third Piagetian stage. In this stage, children can perform operations that involve objects, and they can reason logically when the reasoning can be applied to specific or concrete examples. For instance, concrete operational thinkers cannot imagine the steps necessary to complete an algebraic equation, a task that is too abstract for individuals at this stage of development.
The formal operational stage, which appears between the ages of 11 and 15 and continues through adulthood, is Piaget’s fourth and final stage. In this stage, individuals move beyond concrete experiences and begin to think in abstract and more logical terms. As part of thinking more abstractly, adolescents develop images of ideal circumstances. They might think about what an ideal parent would be like and compare their parents to this ideal standard. They begin to entertain possibilities for the future and are fascinated with what they can be. In solving problems, they become more systematic, developing hypotheses about why something is happening the way it is and then testing these hypotheses. We will examine Piaget’s cognitive developmental theory further in other chapters.

Vygotsky’s Sociocultural Cognitive Theory Like Piaget, the Russian developmentalist Lev Vygotsky (1896–1934) argued that children actively construct their knowledge. However, Vygotsky (1962) gave social interaction and culture far more important roles in cognitive development than PiagetPage 24 did. Vygotsky’s theory is a sociocultural cognitive theory that emphasizes how culture and social interaction guide cognitive development.
Vygotsky portrayed the child’s development as inseparable from social and cultural activities (Daniels, 2017). He maintained that cognitive development involves learning to use the inventions of society, such as language, mathematical systems, and memory strategies. Thus in one culture, children might learn to count with the help of a computer; in another, they might learn by using beads. According to Vygotsky, children’s social interaction with more-skilled adults and peers is indispensable to their cognitive development. Through this interaction, they learn to use the tools that will help them adapt and be successful in their culture (Holzman, 2017). In later chapters, we will examine ideas about learning and teaching that are based on Vygotsky’s theory.
Lev Vygotsky was born the same year as Piaget, but he died much earlier, at the age of 37. There is considerable interest today in Vygotsky’s sociocultural cognitive theory of child development. What are some key characteristics of Vygotsky’s theory?©A.R. Lauria/Dr. Michael Cole, Laboratory of Human Cognition, University of California, San Diego
The Information-Processing Theory Information-processing theory emphasizes that individuals manipulate information, monitor it, and strategize about it. Unlike Piaget’s theory, but like Vygotsky’s theory, information-processing theory does not describe development as stage-like. Instead, according to this theory, individuals develop a gradually increasing capacity for processing information, which allows them to acquire increasingly complex knowledge and skills (Knapp & Morton, 2017).
Robert Siegler (2006, 2017), a leading expert on children’s information processing, states that thinking is information processing. In other words, when individuals perceive, encode, represent, store, and retrieve information, they are thinking. Siegler emphasizes that an important aspect of development is learning good strategies for processing information. For example, becoming a better reader might involve learning to monitor the key themes of the material being read.
Siegler (2006, 2017) also argues that the best way to understand how children learn is to observe them while they are learning. He emphasizes the importance of using the microgenetic method to obtain detailed information about processing mechanisms as they are occurring from moment to moment. Siegler concludes that most research methods indirectly assess cognitive change, being more like snapshots than movies. The microgenetic method seeks to discover not just what children know but the cognitive processes involved in how they acquired the knowledge. A typical microgenetic study will be conducted across a number of trials assessed at various times over weeks or months (Miller, 2015). A number of microgenetic studies have focused on a specific aspect of academic learning, such as how children learn whole number arithmetic, fractions, and other areas of math (Braithwaite & Siegler, 2018; Braithwaite, Tian, & Siegler, 2018). Microgenetic studies also have been used to discover how children learn a particular concept in science or a key component of learning to read.
The information-processing approach often uses the computer as an analogy to help explain the connection between cognition and the brain (Radvansky & Ashcraft, 2018). They describe the physical brain as the computer’s hardware, and cognition as its software. In this analogy, the sensory and perceptual systems provide an “input channel,” similar to the way data are entered into the computer. As input (information) comes into the mind, mental processes, or operations, act on it, just as the computer’s software acts on the data. The transformed input generates information that remains in memory much in the way a computer stores what it has worked on. Finally, the information is retrieved from memory and “printed out” or “displayed” (so to speak) as an observable response.
Computers provide a logical and concrete, but oversimplified, model of the mind’s processing of information. Inanimate computers and human brains function quite differently in some respects. For example, most computers receive information from a human who has already coded the information and removed much of its ambiguity. In contrast, each brain cell, or neuron, can respond to ambiguous information transmitted through sensory receptors such as the eyes and ears.
Computers can do some things better than humans. For instance, computers can perform complex numerical calculations much faster and more accurately than humans could ever hope to. Computers can also apply and follow rules more consistently and with fewer errors than humans and can represent complex mathematical patterns better than humans.
Still, the brain’s extraordinary capabilities will probably not be mimicked completely by computers at any time in the near future (Sternberg, 2017). For example, although a computer can improve its ability to recognize patterns or use rules of thumb to make decisions, it does not have the means to develop new learning goals. Furthermore, the human mind is aware of itself; the computer is not. Indeed, no computer isPage 25 likely to approach the richness of human consciousness.
Nonetheless, the computer’s role in cognitive and developmental psychology continues to increase. An entire scientific field called artificial intelligence (AI) focuses on creating machines capable of performing activities that require intelligence when they are done by people. And a new field titled developmental robotics is emerging that examines various developmental topics and issues using robots, such as motor development, perceptual development, information processing, and language development (Cangelosi & Schlesinger, 2015; Faghihi & Moustafa, 2017; Morse & Cangelosi, 2017). The hope is to build robots that are as much like humans as possible in order to gain a better understanding of human development (Vujovic & others, 2017).
Above is the humanoid robot iCub created by the Italian Institute of Technology to study aspects of children’s development such as perception, cognition, and motor development. In this situation, the robot, the size of a 3.5-year-old child, is catching a ball. This robot is being used by more than 20 laboratories worldwide and has 53 motors that move the head, arms and hands, waist, and legs. It also can see and hear, and has the sense of proprioception (body configuration) and movement (using gyroscopes).©Marco Destefanis/Pacific Press/Sipa/Newscom
Evaluating Cognitive Theories Contributions of cognitive theories include a positive view of development and an emphasis on the active construction of understanding. Criticisms include skepticism about the pureness of Piaget’s stages and too little attention to individual variations.
Behaviorism essentially holds that we can study scientifically only what can be directly observed and measured. Out of the behavioral tradition grew the belief that development is observable behavior that can be learned through experience with the environment (Maag, 2018). In terms of the continuity-discontinuity issue discussed earlier in this chapter, the behavioral and social cognitive theories emphasize continuity in development and argue that development does not occur in stage-like fashion. Let’s explore two versions of behaviorism: Skinner’s operant conditioning and Bandura’s social cognitive theory.
Skinner’s Operant Conditioning According to B. F. Skinner (1904–1990), through operant conditioning the consequences of a behavior produce changes in the probability of the behavior’s occurrence. A behavior followed by a rewarding stimulus is more likely to recur, whereas a behavior followed by a punishing stimulus is less likely to recur. For example, when an adult smiles at a child after the child has done something, the child is more likely to engage in that behavior again than if the adult gives the child a disapproving look.
In Skinner’s (1938) view, such rewards and punishments shape development. For Skinner the key aspect of development is behavior, not thoughts and feelings. He emphasized that development consists of the pattern of behavioral changes that are brought about by rewards and punishments. For example, Skinner would say that shy people learned to be shy as a result of experiences they had while growing up. It follows that modifications in an environment can help a shy person become more socially oriented.

F. Skinner was a tinkerer who liked to make new gadgets. During her first two years of life the younger of his two daughters, Deborah, slept and played in Skinner’s enclosed Air-Crib, which he invented because he wanted to control her environment completely. The Air-Crib was sound-proofed and temperature controlled. Debbie, shown here as a child with her parents, is currently a successful artist, is married, and lives in London. What do you think about Skinner’s Air-Crib?©AP Images

Bandura’s Social Cognitive Theory Some psychologists agree with the behaviorists’ notion that development is learned and is influenced strongly by environmental interactions. However, unlike Skinner, they also see cognition as important in understanding development (Mischel, 2014). Social cognitive theory holds that behavior, environment, and cognition are the key factors in development.
American psychologist Albert Bandura (1925– ) is the leading architect of social cognitive theory. Bandura (1986, 2004, 2010a, b, 2012, 2015) emphasizes that cognitive processes have important links with the environment and behavior. His early research program focused heavily on observational learning (also called imitation or modeling), which is learning that occurs through observing what others do. For example, a young boy might observe his father yelling in anger and treating other people with hostility; with his peers, the young boy later acts very aggressively, showing the same characteristics asPage 26 his father’s behavior. Social cognitive theorists stress that people acquire a wide range of behaviors, thoughts, and feelings through observing others’ behavior and that these observations play a central role in life-span development.
Albert Bandura has been one of the leading architects of social cognitive theory. How does Bandura’s theory differ from Skinner’s?©Linda A Cicero/Stanford News Service
What is cognitive about observational learning in Bandura’s view? He proposes that people cognitively represent the behavior of others and then sometimes adopt this behavior themselves.
Bandura’s (2004, 2010a, b, 2012, 2015) most recent model of learning and development includes three elements: behavior, the person/cognition, and the environment. An individual’s confidence in being able to control his or her success is an example of a person factor; strategies are an example of a cognitive factor. As shown in Figure 13, behavior, person/cognitive, and environmental factors operate interactively.
FIGURE 13 BANDURA’S SOCIAL COGNITIVE MODEL. The arrows illustrate how relations between behavior, person/cognitive, and environment are reciprocal rather than one-way. Person/cognitive refers to cognitive processes (for example, thinking and planning) and personal characteristics (for example, believing that you can control your experiences).
Evaluating Behavioral and Social Cognitive Theories Contributions of the behavioral and social cognitive theories include an emphasis on scientific research and environmental determinants of behavior. Criticisms include too little emphasis on cognition in Skinner’s theory and inadequate attention paid to developmental changes.
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Bandura emphasizes that self-efficacy is a key person/cognitive factor in children’s achievement. Connect to “Socioemotional Development in Middle and Late Childhood.”
Ethology stresses that behavior is strongly influenced by biology, is tied to evolution, and is characterized by critical or sensitive periods. These are specific time frames during which, according to ethologists, the presence or absence of certain experiences has a long-lasting influence on individuals (Bateson, 2015).
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Human babies go through a series of phases in developing an attachment to a caregiver. Connect to “Socioemotional Development in Infancy.”
European zoologist Konrad Lorenz (1903–1989) helped bring ethology to prominence. In his best-known research, Lorenz (1965) studied the behavior of greylag geese, which will follow their mothers as soon as they hatch. Lorenz separated the eggs laid by one goose into two groups. One group he returned to the goose to be hatched by her. The other group was hatched in an incubator. The goslings in the first group performed as predicted. They followed their mother as soon as they hatched. However, those in the second group, which saw Lorenz when they first hatched, followed him everywhere, as though he were their mother. Lorenz marked the goslings and then placed both groups under a box. Mother goose and “mother” Lorenz stood aside as the box was lifted. Each group of goslings went directly to its “mother.” Lorenz called this process imprinting—the rapid, innate learning that involves attachment to the first moving object seen.
Konrad Lorenz, a pioneering student of animal behavior, is followed through the water by three imprinted greylag geese. Describe Lorenz’s experiment with the geese. Do you think his experiment would have had the same results with human babies? Explain.©Nina Leen/Time Life Pictures/Getty Images
John Bowlby (1969, 1989) illustrated an important applicationPage 27 of ethological theory to human development. Bowlby stressed that attachment to a caregiver over the first year of life has important consequences throughout the life span. In his view, if this attachment is positive and secure, the individual will likely develop positively in childhood and adulthood. If the attachment is negative and insecure, life-span development will likely not be optimal. We will explore the concept of infant attachment in much greater detail later in this edition.
In Lorenz’s view, imprinting needs to take place at a certain, very early time in the life of the animal, or else it will not take place. This point in time is called a critical period. A related concept is that of a sensitive period, and an example of this is the time during infancy when, according to Bowlby, attachment should occur in order to promote optimal development of social relationships.
Another theory that emphasizes biological foundations of development—evolutionary psychology—will be presented in the chapter on “Biological Beginnings,” along with views on the role of heredity in development (Lickliter, 2018). In addition, we will examine a number of biological theories of aging in later chapters (Kauppila, Kauppila, & Larsson, 2017).
Contributions of ethological theory include a focus on the biological and evolutionary basis of development, and the use of careful observations in naturalistic settings. Criticisms include too much emphasis on biological foundations and a belief that the critical and sensitive period concepts might be too rigid.
While ethological theory stresses biological factors, ecological theory emphasizes environmental factors. One ecological theory that has important implications for understanding life-span development was created by Urie Bronfenbrenner (1917–2005). Bronfenbrenner’s ecological theory (Bronfenbrenner, 1986, 2004; Bronfenbrenner & Morris, 1998, 2006) holds that development reflects the influence of several environmental systems. The theory identifies five environmental systems: microsystem, mesosystem, exosystem, macrosystem, and chronosystem (see Figure 14).
FIGURE 14 Bronfenbrenner’s Ecological Theory of Development. Bronfenbrenner’s ecological theory consists of five environmental systems: microsystem, mesosystem, exosystem, macrosystem, and chronosystem.
The microsystem is the setting in which the individual lives. These contexts include the person’s family, peers, school, and neighborhood. It is in the microsystem that the most direct interactions with social agents take place—with parents, peers, and teachers, for example. The individual is not a passive recipient of experiences in these settings, but someone who helps to construct the settings.
The mesosystem involves relations between microsystems or connections between contexts. Examples are the relation of family experiences to school experiences, school experiences to religious experiences, and family experiences to peer experiences. For example, children whose parents have rejected them may have difficulty developing positive relationships with teachers.
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How are parent-child relationships and children’s peer relations linked? Connect to “Socioemotional Development in Early Childhood.”
The exosystem consists of links between a social setting in which the individual does not have an active role and the individual’s immediate context. For example, a husband’s or child’s experiences at home may be influenced by a mother’s experiences at work. The mother might receive a promotion that requires more travel, which might increase conflict with the husband and change patterns of interaction with the child.
The macrosystem involves the culture in which individuals live. Remember from earlier in the chapter that culture refers to the behavior patterns, beliefs, and all other products of a group of people that are passed on from generation to generation. Remember also that cross-cultural studies—the comparison of one culture with one or more other cultures—provide information about the generality of development.
The chronosystem consists of the patterning of environmental events and transitions over the life course, as well as sociohistorical circumstances. For example, divorce is one transition. Researchers have found that the negative effects of divorce on children often peak during the first year after the divorcePage 28 (Hetherington, 1993, 2006). By two years after the divorce, family interaction has become more stable. As an example of sociohistorical circumstances, consider how career opportunities for women have increased since the 1960s.
Bronfenbrenner (2004; Bronfenbrenner & Morris, 2006) subsequently added biological influences to his theory, describing it as a bioecological theory. Nonetheless, it is still dominated by ecological, environmental contexts.
Contributions of ecological theory include a systematic examination of macro and micro dimensions of environmental systems, and attention to connections between environmental systems. A further contribution of Bronfenbrenner’s theory is an emphasis on a range of social contexts beyond the family, such as neighborhood, religion, school, and workplace, as influential in children’s development (Shelton, 2018). Criticisms include inadequate attention to biological factors, as well as too little emphasis on cognitive factors.
Urie Bronfenbrenner developed ecological theory, a perspective that is receiving increased attention today. His theory emphasizes the importance of both micro and macro dimensions of the environment in which the child lives.Courtesy of Cornell University
No single theory described in this chapter can explain entirely the rich complexity of life-span development, but each has contributed to our understanding of development. Psychoanalytic theory best explains the unconscious mind. Erikson’s theory best describes the changes that occur during adult development. Piaget’s, Vygotsky’s, and the information-processing views provide the most complete description of cognitive development. The behavioral and social cognitive and ecological theories have been the most adept at examining the environmental determinants of development. The ethological theories have highlighted biology’s role and the importance of sensitive periods in development.
In short, although theories are helpful guides, relying on a single theory to explain development is probably a mistake. This book instead takes an eclectic theoretical orientation, which does not follow any one theoretical approach but rather selects from each theory whatever is considered its best features. In this way, you can view the study of development as it actually exists—with different theorists making different assumptions, stressing different empirical problems, and using different strategies to discover information. Figure 15 compares the main theoretical perspectives in terms of how they view important issues in life-span development.
Review Connect Reflect
LG3 Describe the main theories of human development.

What are the four steps of the scientific method? How can theory and hypotheses be defined? What are two main psychoanalytic theories? What are some contributions and criticisms of the psychoanalytic theories?
What are three main cognitive theories? What are some contributions and criticisms of the cognitive theories?
What are two main behavioral and social cognitive theories? What are some contributions and criticisms of the behavioral and social cognitive theories?
What is the nature of ethological theory? What are some contributions and criticisms of the theory?
What characterizes ecological theory? What are some contributions and criticisms of the theory?
What is an eclectic theoretical orientation?


The beginning of this section started with a question about whether special care might be able to repair the harm inflicted by child neglect. How might this question be answered differently using the various theories outlined?

Reflect Your Own Personal Journey of Life

Which of the life-span theories do you think best explains your own development? Why?

4 Research on Life-Span Development
LG4 Explain how research on life-span development is conducted.
Methods for Collecting Data
Research Designs
Time Span of Research
Conducting Ethical Research
Minimizing Bias
If they follow an eclectic orientation, how do scholars and researchers determine that one feature of a theory is somehow better than another? Through scientific research, the features of theories can be tested and refined (Smetana, 2018; Smith & Davis, 2016).
Generally, research on life-span development is designed to test hypotheses, which in some cases are derived from the theories just described. Through research, theories are modified to reflect new data, and occasionally new theories arise. How are data about life-span development collected? What types of research designs are used to study life-span development? And what are some ethical considerations in conducting research on life-span development?
Science refines everyday thinking.
—Albert Einstein
German-born American Physicist, 20th Century
Whether we are interested in studying attachment in infants, the cognitive skills of children, or social relationships in older adults, we can choose from several ways of collecting data (Salkind, 2017). Here we outline the measures most often used, beginning with observation.
Observation Scientific observation requires an important set of skills. For observations to be effective, they have to be systematic. We have to have some idea of what we are looking for. We have to know whom we are observing, when and where we will observe, how the observations will be made, and how they will be recorded.
Where should we make our observations? We have two choices: the laboratory and the everyday world.
When we observe scientifically, we often need to control certain factors that determine behavior but are not the focus of our inquiry (Leary, 2017). For this reason, some research on life-span development is conducted in a laboratory, a controlled setting where many of the complex factors of the “real world” are absent. For example, suppose you want to observe how children react when they see other people act aggressively. If you observe children in their homes or schools, you have no control over Page 30how much aggression the children observe, what kind of aggression they see, which people they see acting aggressively, or how other people treat the children. In contrast, if you observe the children in a laboratory, you can control these and other factors and therefore have more confidence about how to interpret your observations.
Laboratory research does have some drawbacks, however, including the following:

It is almost impossible to conduct research without the participants knowing they are being studied.
The laboratory setting is unnatural and therefore can cause the participants to behave unnaturally.
People who are willing to come to a university laboratory may not accurately represent groups from diverse cultural backgrounds.
People who are unfamiliar with university settings and with the idea of “helping science” may be intimidated by the laboratory setting.

Naturalistic observation provides insights that sometimes cannot be attained in the laboratory (Babbie, 2017). Naturalistic observation means observing behavior in real-world settings, making no effort to manipulate or control the situation. Life-span researchers conduct naturalistic observations at sporting events, child-care centers, work settings, malls, and other places people live in and frequent.
Naturalistic observation was used in one study that focused on conversations in a children’s science museum (Crowley & others, 2001). When visiting exhibits at the science museum, parents were far more likely to engage boys than girls in explanatory talk. This finding suggests a gender bias that encourages boys more than girls to be interested in science (see Figure 16).
FIGURE 16 Parents’ Explanations of Science to Sons and Daughters at a Science Museum. In a naturalistic observation study at a children’s science museum, parents were three times more likely to explain science to boys than to girls (Crowley & others, 2001). The gender difference occurred regardless of whether the father, the mother, or both parents were with the child, although the gender difference was greatest for fathers’ science explanations to sons and daughters.
Survey and Interview Sometimes the best and quickest way to get information about people is to ask them for it. One technique is to interview them directly. A related method is the survey (sometimes referred to as a questionnaire), which is especially useful when information from many people is needed. A standard set of questions is used to obtain peoples’ self-reported attitudes or beliefs about a particular topic. In a good survey, the questions are clear and unbiased, allowing respondents to answer unambiguously.
Surveys and interviews can be used to study topics ranging from religious beliefs to sexual habits to attitudes about gun control to beliefs about how to improve schools. Surveys and interviews may be conducted in person, over the telephone, and over the Internet.
One problem with surveys and interviews is the tendency of participants to answer questions in a way that they think is socially acceptable or desirable rather than to say what they truly think or feel (Madill, 2012). For example, on a survey or in an interview some individuals might say that they do not take drugs even though they do.
What are some important strategies in conducting observational research with children?©Philadelphia Inquirer/MCT/Landov Images
Standardized Test A standardized test has uniform procedures for administration and scoring. Many standardized tests allow a person’s performance to be compared with that of other individuals; thus they provide information about individual differences among people (Kaplan & Saccuzzo, 2018). One example is the Stanford-Binet intelligence test, which will be discussed in more detail later. Your score on the Stanford-Binet test tells you how your performance compares with that of thousands of other people who have taken the test.
One criticism of standardized tests is that they assume a person’s behavior is consistent and stable, yet personality and intelligence—two primary targets of standardized testing—can vary with the situation. For example, a person may perform poorly on a standardized intelligence test in an office setting but score much higher at home, where he or she is less anxious.
Case Study A case study is an in-depth look atPage 31 a single individual. Case studies are performed mainly by mental health professionals when, for either practical or ethical reasons, the unique aspects of an individual’s life cannot be duplicated and tested in other individuals. A case study provides information about one person’s experiences; it may focus on nearly any aspect of the subject’s life that helps the researcher understand the person’s mind, behavior, or other attributes (Yin, 2012). A researcher may gather information for a case study from interviews and medical records. In later chapters, we discuss vivid case studies, such as that of Michael Rehbein, who had much of the left side of his brain removed at 7 years of age to end severe epileptic seizures.
A case study can provide a dramatic, in-depth portrayal of an individual’s life, but we must be cautious when generalizing from this information. The subject of a case study is unique, with a genetic makeup and personal history that no one else shares. In addition, case studies involve judgments of unknown reliability. Researchers who conduct case studies rarely check to see if other professionals agree with their observations or findings.
Mahatma Gandhi was the spiritual leader of India in the middle of the twentieth century. Erik Erikson conducted an extensive case study of Gandhi’s life to determine what contributed to his identity development. What are some limitations of the case study approach?©Bettmann/Getty Images
Physiological Measures Researchers are increasingly using physiological measures when they study development at different points in the life span (Bell & others, 2018). Hormone levels are increasingly used in developmental research.
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Cognitive Neuroscience and Aging
The cognitive neuroscience of aging involves the study of links between the brain’s development in older adults and changes in their cognitive skills. Connect to “Cognitive Development in Late Adulthood.”
Cortisol is a hormone produced by the adrenal gland that is linked to the body’s stress level and has been measured in studies of temperament, emotional reactivity, mood, and peer relations (Bangerter & others, 2017). Also, as puberty unfolds, the blood levels of certain hormones increase. To determine the nature of these hormonal changes, researchers analyze blood samples from adolescent volunteers (Ji & others, 2016).
Another physiological measure that is increasingly being used is neuroimaging, especially functional magnetic resonance imaging (fMRI), in which electromagnetic waves are used to construct images of a person’s brain tissue and biochemical activity (Park & Festini, 2018; Sullivan & Wilson, 2018). Figure 17 compares the brain images of two adolescents—one a non-drinker and the other a heavy drinker—while they are engaged in a memory task.
FIGURE 17 Brain Imaging of 15-Year-Old Adolescents. These two brain images indicate how alcohol can influence the functioning of an adolescent’s brain. Notice the pink and red coloring (which indicates effective brain functioning involving memory) in the brain of the 15-year-old non-drinker (left) while engaging in a memory task, and compare it with the lack of those colors in the brain of the 15-year-old heavy drinker (right) under the influence of alcohol.©Dr. Susan Tapert, University of California, San Diego
Electroencephalography (EEG) is a physiological measure that has been used for many decades to monitor overall electrical activity in the brain (Najjar & Brooker, 2017). Recent electroencephalograph researchPage 32 includes studies of infants’ attention and memory (Bell & others, 2018; Lusby & others, 2016). In many chapters of this edition, you will read about recent research on changes in the brain during prenatal development, infancy, childhood, adolescence, and aging.
developmental connection
Gene × Environment (G × E) Interaction
Increasingly, researchers are exploring how the interaction of a specific gene and a specific aspect of the environment affects development. Connect to “Biological Beginnings.”
Heart rate has been used as an indicator of infants’ and children’s development of perception, attention, and memory (Kim, Yang, & Lee, 2015). Further, heart rate has served as an index of different aspects of emotional development, such as inhibition, stress, and anxiety (Amole & others, 2017).
Researchers study eye movement to learn more about perceptual development and other developmental topics. Sophisticated eye-tracking equipment is especially being used to discover more detailed information about infants’ perception (Boardman & Fletcher-Watson, 2017), attention (Meng, Uto, & Hashiya, 2017), autism (Finke, Wilkinson, & Hickerson, 2017), and preterm birth effects on language development (Loi & others, 2017).
Yet another dramatic change in physiological methods is the advancement in methods to assess the actual units of hereditary information—genes—in studies of biological influences on development (Xing & others, 2018). For example, recent advances in gene assessment have revealed several specific genes that are linked to childhood obesity (Zandona & others, 2017). Also, in a later chapter you will read about the role of the ApoE4 gene in Alzheimer disease (Lancaster, Tabet, & Rusted, 2017; Parcon & others, 2018; Park & Festini, 2018).
When you are conducting research on life-span development, in addition to selecting a method for collecting data, you also need to choose a research design (Jackson, 2017). There are three main types of research designs: descriptive, correlational, and experimental.
Descriptive Research All of the data-collection methods that we have discussed can be used in descriptive research, which aims to observe and record behavior. For example, a researcher might observe the extent to which people are altruistic or aggressive toward each other. By itself, descriptive research cannot prove what causes some phenomenon, but it can reveal important information about people’s behavior (Gravetter & Forzano, 2017).
Correlational Research In contrast with descriptive research, correlational research goes beyond describing phenomena to provide information that will help us to predict how people will behave (Gravetter & Forzano, 2017). In correlational research, the goal is to describe the strength of the relationship between two or more events or characteristics. The more strongly the two events are correlated (or related or associated), the more accurately we can predict one event from the other (Aron, Aron, & Coups, 2017).
For example, to find out whether children of permissive parents have less self-control than other children, you would need to carefully record observations of parents’ permissiveness and their children’s self-control. You might observe that the higher a parent was in permissiveness, the lower the child was in self-control. You would then analyze these data statistically to yield a numerical measure called a correlation coefficient, which is a number based on a statistical analysis that describes the degree of association between two variables. The correlation coefficient ranges from −1.00 to +1.00. A negative number means an inverse relation. In this example, you might find an inverse correlation between permissive parenting and children’s self-control with a coefficient of, say, −.30. By contrast, you might find a positive correlation of +.30 between parental monitoring of children and children’s self-control.
The higher the correlation coefficient (whether positive or negative), the stronger the association between the two variables. A correlation of 0 means that there is no association between the variables. A correlation of −.40 is stronger than a correlation of +.20 because we disregard whether the correlation is positive or negative in determining the strength of the correlation.
A caution is in order, however. Correlation does not equal causation (Howell, 2017). The correlational finding just mentioned does not mean that permissive parenting necessarily causes low self-control in children. It could have that meaning, but it also could indicate that a child’s lack of self-control caused the parents to throw up their arms in despair and give up trying to control the child. It also could mean that other factors, such as heredity or poverty, caused the correlation between permissive parenting and low self-control in children. Figure 18 illustrates these possible interpretations of correlational data.
Experimental Research To study causality, researchersPage 33 turn to experimental research. An experiment is a carefully regulated procedure in which one or more factors believed to influence the behavior being studied are manipulated while all other factors are held constant. If the behavior under study changes when a factor is manipulated, we say that the manipulated factor has caused the behavior to change. In other words, the experiment has demonstrated cause and effect. The cause is the factor that was manipulated. The effect is the behavior that changed because of the manipulation. Nonexperimental research methods (descriptive and correlational research) cannot establish cause and effect because they do not involve manipulating factors in a controlled way.
Independent and Dependent Variables Experiments include two types of changeable factors, or variables: independent and dependent. An independent variable is a manipulated, influential, experimental factor. It is a potential cause. The label “independent” is used because this variable can be manipulated independently of other factors to determine its effect. An experiment may include one independent variable or several of them.
A dependent variable is a factor that can change in an experiment, in response to changes in the independent variable. As researchers manipulate the independent variable, they measure the dependent variable for any resulting effect.
For example, suppose that you conducted a study to determine whether women could change the breathing and sleeping patterns of their newborn babies by meditating during pregnancy. You might require one group of pregnant women to engage in a certain amount and type of meditation each day while another group would not meditate; the meditation is thus the independent variable. When the infants are born, you would observe and measure their breathing and sleeping patterns. These patterns are the dependent variable, the factor that changes as the result of your manipulation.
Experimental and Control Groups Experiments can involve one or more experimental groups and one or more control groups (Gravetter & Forzano, 2017). An experimental group is a group whose experience is manipulated. A control group is a comparison group that is as similar to the experimental group as possible and that is treated in every way like the experimental group except for the manipulated factor (independent variable). The control group serves as a baseline against which the effects of the manipulated condition can be compared.
Random assignment is an important principle for deciding whether each participant will be placed in the experimental group or in the control group. Random assignment means that researchers assign participants to experimental and control groups by chance. It reduces the likelihood that the experiment’s results will be due to any preexisting differences between groups. In the example involving the effects of meditation by pregnant women on the breathing and sleeping patterns of their newborns, you would randomly assign half of the pregnant women to engage in meditation over a period of weeks (the experimental group) and the other half to not meditate over the same number of weeks (the control group). Figure 19 illustrates the nature of experimental research.
FIGURE 19 Principles of Experimental Research. Imagine that you decide to conduct an experimental study of the effects of meditation by pregnant women on their newborns’ breathing and sleeping patterns. You would randomly assign pregnant women to experimental and control groups. The experimental-group women would engage in meditation over a specified number of sessions and weeks. The control group would not. Then, when the infants are born, you would assess their breathing and sleeping patterns. If the breathing and sleeping patterns of newborns whose mothers were in the experimental group are more positive than those of the control group, you would conclude that meditation caused the positive effects.Page 34
Researchers in life-span development have a special concern with studies that focus on the relation of age to some other variable. We have several options: Researchers can study different individuals of varying ages and compare them or they can study the same individuals as they age over time.
Cross-Sectional Approach The cross-sectional approach is a research strategy that simultaneously compares individuals of different ages. A typical cross-sectional study might include three groups of children: 5-year-olds, 8-year-olds, and 11-year-olds. Another study might include groups of 15-year-olds, 25-year-olds, and 45-year-olds. The groups can be compared with respect to a variety of dependent variables: IQ, memory, peer relations, attachment to parents, hormonal changes, and so on. All of this can be accomplished in a short time. In some studies, data are collected in a single day. Even in large-scale cross-sectional studies with hundreds of subjects, data collection does not usually take longer than several months to complete.
The main advantage of the cross-sectional study is that the researcher does not have to wait for the individuals to grow up or become older. Despite its efficiency, though, the cross-sectional approach has its drawbacks. It gives no information about how individuals change or about the stability of their characteristics. It can obscure the increases and decreases of development—the hills and valleys of growth and development. For example, a cross-sectional study of life satisfaction might reveal average increases and decreases, but it would not show how the life satisfaction of individual adults waxed and waned over the years. It also would not tell us whether the same adults who had positive or negative perceptions of life satisfaction in early adulthood maintained their relative degree of life satisfaction as they became middle-aged or older adults.
Longitudinal Approach The longitudinal approach is a research strategy in which the same individuals are studied over a period of time, usually several years or more. For example, in a longitudinal study of life satisfaction, the same adults might be assessed periodically over a 70-year time span—at the ages of 20, 35, 45, 65, and 90, for example.
Longitudinal studies provide a wealth of information about vital issues such as stability and change in development and the influence of early experience on later development, but they do have drawbacks (Almy & Cicchetti, 2018). They are expensive and time-consuming. The longer the study lasts, the more participants drop out—they move, get sick, lose interest, and so forth. The participants who remain may be dissimilar to those who drop out, biasing the outcome of the study. Those individuals who remain in a longitudinal study over a number of years may be more responsible and conformity-oriented, for example, or they might lead more stable lives.
Cohort Effects A cohort is a group of people who are born at a similar point in history and share similar experiences as a result, such as living through the Vietnam War or growing up in the same city around the same time. These shared experiences may produce a range of differences among cohorts (Ganguli, 2017; Messerlian & Basso, 2018; Schaie, 2016a, b). For example, people who were teenagers during the Great Depression are likely to differ from people who were teenagers during the booming 1990s in regard to their educational opportunities and economic status, how they were raised, and their attitudes toward sex and religion. In life-span development research, cohort effects are due to a person’s time of birth, era, or generation but not to actual age.
developmental connection
Cohort effects help to explain differences in the intelligence of people born at different points in time. Connect to “Physical and Cognitive Development in Middle Adulthood.”
Cohort effects are important because they can powerfully affect the dependent measures in a study ostensibly concerned with age (Grondahl & others, 2017; MacDonald & Stawski, 2016). Researchers have shown that it is especially important to be aware of cohort effects when assessing adult intelligence (Schaie, 2016a, b). Individuals born at different points in time—such as 1920, 1940, and 1960—have had varying opportunities for education. Individuals born in earlier years had less access to education, and this fact may have a significant effect on how this cohort performs on intelligence tests. Some researchers have found that cross-sectional studies indicate more than 90 percent of cognitive decline in aging is due to a slowing of processing speed, whereas longitudinal studies reveal that 20 percent or less of cognitive decline is due to processing speed (MacDonald & others, 2003; MacDonald & Stawski, 2015, 2016; Stawski, Sliwinski, & Hofer, 2013).
A recent example of a cohort effect occurred in a study in which older adults assessed in 2013–2014 engaged in a higher level of abstract reasoning than their counterparts assessed two decades earlier in 1990–1993 (Gerstorf & others, 2015). Another study illustrated how even a 10-year difference in when people are born can produce differences in cognitive and health outcomes (Christensen & others, 2013). In this study, Danish cohorts bornPage 35 in 1905 and 1915 were compared when each cohort reached their nineties, with the 1915 cohort showing significantly better cognitive and health profiles.
Cohort effects are due to a person’s time of birth or generation but not actually to age. Think for a moment about growing up in (left) the Great Depression and (right) today. How might your development differ depending on which of these time frames has dominated your life? your parents’ lives? your grandparents’ lives?(Left) Source: George Grantham Bain Collection, Library of Congress, Reproduction Number #LC-USZ62-63966; (right) ©Jamie Grill/Blend Images
Cross-sectional studies can show how different cohorts respond, but they can confuse age changes and cohort effects. Longitudinal studies are effective in studying age changes but only within one cohort.
Various generations have been given labels by the popular culture. Figure 20 describes the labels given to various generations, their historical periods, and the reasons for these labels. Consider the following description of the current generation of youth and think about how they differ from earlier youth generations:
FIGURE 20 Generations, Their Historical Periods, and Characteristics
They are history’s first “always connected” generation. Steeped in digital technology and social media, they treat their multi-tasking hand-held gadgets almost like a body part—for better or worse. More than 8 in 10 say they sleep with a cell phone glowing by the bed, poised to disgorge texts, phone calls, e-mails, songs, news, videos, games, and wake-up jingles. But sometimes convenience yields to temptation. Nearly two-thirds admit to texting while driving (Pew Research Center, 2010, p. 1).
How are today’s millennials experiencing youth differently from earlier generations?©Mark Bowden/Getty ImagesPage 36
Ethics in research may affect you personally if you ever serve as a participant in a study. In that event, you need to know your rights as a participant and the responsibilities of researchers to assure that these rights are safeguarded.
If you ever become a researcher in life-span development yourself, you will need an even deeper understanding of ethics. Even if you only carry out experimental projects in psychology courses, you must consider the rights of the participants in those projects (Salkind, 2017). A student might think, “I volunteer in a home for people with intellectual disabilities several hours per week. I can use the residents of the home in my study to see if a particular treatment helps improve their memory for everyday tasks.” But without proper permissions, the most well-meaning, kind, and considerate studies still violate the rights of the participants.
Today, proposed research at colleges and universities must pass the scrutiny of a research ethics committee before the research can be initiated (Kazdin, 2017; Leary, 2017). In addition, the American Psychological Association (APA) has developed ethics guidelines for its members. The code of ethics instructs psychologists to protect their participants from mental and physical harm. The participants’ best interests need to be kept foremost in the researcher’s mind. APA’s guidelines address four important issues:

Informed consent. All participants must know what their research participation will involve and what risks might develop. Even after informed consent is given, participants must retain the right to withdraw from the study at any time and for any reason.
Confidentiality. Researchers are responsible for keeping all of the data they gather on individuals completely confidential and, when possible, completely anonymous.
Debriefing. After the study has been completed, participants should be informed of its purpose and the methods that were used. In most cases, the experimenter also can inform participants in a general manner beforehand about the purpose of the research without leading participants to behave in a way they think that the experimenter is expecting.
Deception. In some circumstances, telling the participants beforehand what the research study is about substantially alters the participants’ behavior and invalidates the researcher’s data. In all cases of deception, however, the psychologist must ensure that the deception will not harm the participants and that the participants will be debriefed (told the complete nature of the study) as soon as possible after the study is completed.

Studies of life-span development are most useful when they are conducted without bias or prejudice toward any particular group of people. Of special concern is bias based on gender and bias based on culture or ethnicity.
Gender Bias For most of its existence, our society has had a strong gender bias, a preconceived notion about the abilities of women and men that prevented individuals from pursuing their own interests and achieving their potential (Brannon, 2017; Helgeson, 2017). Gender bias also has had a less obvious effect within the field of life-span development. For example, it is not unusual for conclusions to be drawn about females’ attitudes and behaviors from research conducted with males as the only participants.
Furthermore, when researchers find gender differences, their reports sometimes magnify those differences (Denmark & others, 1988). For example, a researcher might report that 74 percent of the men in a study had high achievement expectations versus only 67 percent of the women and go on to talk about the differences in some detail. In reality, this might be a rather small difference. It also might disappear if the study were repeated, or the study might have methodological problems that don’t allow such strong interpretations.
Pam Reid is a leading researcher who studies the effects of gender and ethnic bias on development. You can read about Dr. Reid’s interests in Connecting with Careers.
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connecting with careers
Pam Reid, Educational and Developmental Psychologist
When she was a child, Pam Reid liked to play with chemistry sets. Reid majored in chemistry during college and wanted to become a doctor. However, when some of her friends signed up for a psychology class as an elective, she decided to take the course. She was intrigued by learning about how people think, behave, and develop—so much so that she changed her major to psychology. Reid went on to obtain her Ph.D. in psychology (American Psychological Association, 2003, p. 16).
Pam Reid (center) with students at the University of Saint Joseph.Courtesy of Dr. Pam Reid
For a number of years, Reid was a professor of education and psychology at the University of Michigan, where she also was a research scientist at the Institute for Research on Women and Gender. Her main focus has been on how children and adolescents develop social skills, with a special interest in the development of African American girls (Reid & Zalk, 2001). She has been involved in numerous community activities, including the creation of a math and technology enrichment program for middle-school girls. In 2004, Reid became provost and executive vice-president at Roosevelt University in Chicago. From 2008 to 2015, she was president of the University of Saint Joseph in Hartford, Connecticut, before retiring to pursue other interests.
For more information about what educational psychologists do, see the Careers in Life-Span Development appendix.
Cultural and Ethnic Bias Today there is a growing realization that research on life-span development needs to include more people from diverse ethnic groups (Nieto & Bode, 2018). Historically, people from ethnic minority groups (African American, Latino, Asian American, and Native American) were excluded from most research in the United States and simply thought of as variations from the norm or average. If minority individuals were included in samples and their scores didn’t fit the norm, they were viewed as confounds or “noise” in data and discounted. Given the fact that individuals from diverse ethnic groups were excluded from research on life-span development for so long, we might reasonably conclude that people’s real lives are perhaps more varied than research data have indicated in the past.
Researchers also have tended to overgeneralize about ethnic groups (Schaefer, 2015). Ethnic gloss is using an ethnic label such as African American or Latino in a superficial way that portrays an ethnic group as being more homogeneous than it really is (Trimble, 1988). For example, a researcher might describe a research sample like this: “The participants were 60 Latinos.” A more complete description of the group might be something like this: “The 60 Latino participants were Mexican Americans from low-income neighborhoods in the southwestern area of Los Angeles. Thirty-six were from homes in which Spanish is the dominant language spoken, 24 from homes in which English is the main language spoken. Thirty were born in the United States, 30 in Mexico. Twenty-eight described themselves as Mexican American, 14 as Mexican, 9 as American, 6 as Chicano, and 3 as Latino.” Ethnic gloss can cause researchers to obtain samples of ethnic groups that are not representative of the group’s diversity, which can lead to overgeneralization and stereotyping.
Look at these two photographs, one of all non-Latino White males, the other of a diverse group of females and males from different ethnic groups, including some non-Latino White males. Consider a topic in life-span development, such as parenting, love, or cultural values. If you were conducting research on this topic, might the results of the study differ depending on whether the participants in your study were the individuals in the photograph on the left or on the right?(Left) ©Anthony Cassidy/The Image Bank/Getty Images; (right) ©Punchstock/Digital Vision
Ross Parke and Raymond Buriel (2006) described how research on ethnic minority children and their families has not been given adequate attention, especially in light of their significant rates of growth. Until recently, ethnic minority families were combined in the category “minority,” which masks important differences among ethnic groups as well as diversity within an ethnic group. When research has been conducted on ethnic groups, most often they are compared to non–Latino Whites to identify group differences. An assumption in two-group studies is that ethnic minority children have not advanced far enough to be the same as non–Latino White children and that this developmentalPage 38 lag contributes to ethnic minority children’s problems. Recently, some researchers have replaced two-group studies with more in-depth examination of variations within a single ethnic group. For example, a researcher might study how parents in an ethnic group adapt to the challenges they face as a minority in U.S. society and how these experiences contribute to the goals they have for their children. The continued growth of minority families in the United States in approaching decades will mainly be due to the immigration of Latino and Asian families (Bas-Sarmiento & others, 2017; Lo & others, 2017). Researchers need “to take into account their acculturation level and generational status of parents and children,” and consider how these factors might influence family processes and child outcomes (Parke & Buriel, 2006, p. 487). More attention also needs to be given to biculturalism because the complexity of diversity means that some children of color identify with two or more ethnic groups (Coard, 2017; Nieto & Bode, 2018). And language development research needs to focus more on second-language acquisition (usually English) and bilingualism and how they are linked to school achievement (Echevarria, Vogt, & Short, 2017).
Review Connect Reflect
LG4 Explain how research on life-span development is conducted.

What methods do researchers use to collect data on life-span development?
What research designs are used to study human development?
How is research conducted on the time span of people’s lives?
What are researchers’ ethical responsibilities to the people they study?
How can gender, cultural, and ethnic bias affect the outcome of a research study?


Earlier in the chapter, you read about normative age-graded influences, normative history-graded influences, and nonnormative life events. Describe how these influences relate to what you just read about cohort effects.

Reflect Your Own Personal Journey of Life

You and your parents grew up at different points in time. Consider some ways that you are different from your parents. Do you think some of your differences might be due to cohort effects? Explain.

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topical connections looking forward
In the chapter on “Biological Beginnings,” you will continue to learn about theory and research as you explore the biological underpinnings of life-span development. The influence of human evolution on development will be covered, including a discussion of natural selection and adaptive behavior. You will examine how the human genome works, the collaborative nature of genes, and how DNA plays a role in creating the person each of us becomes. You also will explore the challenges and choices people encounter when deciding to reproduce, including infertility treatments and adoption. And you will read in greater depth about the many sides of the age-old nature-nurture debate, focusing on the way heredity and environment interact.
reach your learning goals
1 The Life-Span Perspective
LG1 Discuss the distinctive features of a life-span perspective on development.
The Importance of Studying Life-Span Development
Characteristics of the Life-Span Perspective
Some Contemporary Concerns

Development is the pattern of change that begins at conception and continues through the human life span. It includes both growth and decline.
Studying life-span development helps prepare us to take responsibility for children, gives us insight about our own lives, and gives us knowledge about what our lives will be like as we age.
Life expectancy has increased dramatically in the last century, but life span has remained virtually the same.
The life-span perspective includes these basic concepts: development is lifelong, multidimensional, multidirectional, and plastic; its study is multidisciplinary; it is contextual; it involves growth, maintenance, and regulation of loss; and it is a co-construction of biological, cultural, and individual factors.
Three important sources of contextual influences are (1) normative age-graded influences, (2) normative history-graded influences, and (3) nonnormative life events.
Health and well-being, parenting, education, sociocultural contexts and diversity, social policy, and technology are all areas of contemporary concern that are closely tied to life-span development.
Important dimensions of the sociocultural context include culture, ethnicity, socioeconomic status, and gender.
There is increasing interest in social policy issues related to children and to older adults.
Recently, there also has been a dramatic infusion of technology in the lives of people of all ages, and the influence of technology on development is an important contemporary issue.

2 The Nature of Development
LG2 Identify the most important processes, periods, and issues in development.
Biological, Cognitive, and Socioemotional Processes
Periods of Development
The Significance of Age
Developmental Issues

Three key categories of developmental processes are biological, cognitive, and socioemotional. Throughout development, there are extensive connections between these types of processes.
The life span is commonly divided into the followingPage 40 development periods: prenatal, infancy, early childhood, middle and late childhood, adolescence, early adulthood, middle adulthood, and late adulthood.
Recently, life-span developmentalists have described the human life span in terms of four ages, with a special focus on the third and fourth ages, as well as a distinction between the young-old and oldest-old.
An important aspect of life-span development involves connections across periods of development.
According to some experts on life-span development, too much emphasis is placed on chronological age.
In studies covering adolescence through late adulthood, older people report the highest level of happiness.
We often think of age only in terms of chronological age, but a full evaluation of age requires consideration of chronological, biological, psychological, and social age. Neugarten emphasizes that we are moving toward a society in which chronological age is only a weak predictor of development in adulthood.
The nature-nurture issue focuses on the extent to which development is mainly influenced by nature (biological inheritance) or nurture (experience).
The stability-change issue focuses on the degree to which we become older renditions of our early experience or develop into someone different from who we were earlier in development. A special aspect of the stability-change issue is the extent to which development is determined by early versus later experiences.
Developmentalists describe development as continuous (gradual, or cumulative change) or as discontinuous (abrupt, or a sequence of stages). Most developmentalists recognize that extreme positions on the nature-nurture, stability-change, and continuity-discontinuity issues are unwise. Despite this consensus, there is still spirited debate on these issues.

3 Theories of Development
LG3 Describe the main theories of human development.
Psychoanalytic Theories
Cognitive Theories
Behavioral and Social Cognitive Theories Ethological Theory
Ecological Theory
An Eclectic Theoretical Orientation

The scientific method involves four main steps: (1) conceptualize a problem, (2) collect data, (3) analyze data, and (4) draw conclusions.
Theory is often involved in conceptualizing a problem. A theory is a coherent set of interrelated ideas that helps to explain phenomena and to facilitate predictions. Hypotheses are specific assertions and predictions, often derived from theory, that can be tested.
According to psychoanalytic theories, development primarily depends on the unconscious mind and is heavily couched in emotion. Freud argued that individuals go through five psychosexual stages. Erikson’s theory emphasizes eight psychosocial stages of development: trust versus mistrust, autonomy versus shame and doubt, initiative versus guilt, industry versus inferiority, identity versus identity confusion, intimacy versus isolation, generativity versus stagnation, and integrity versus despair.
Contributions of psychoanalytic theories include an emphasis on a developmental framework, family relationships, and unconscious aspects of the mind. C