CHAPTER 11
PHYSICAL AND COGNITIVE DEVELOPMENT
IN ADOLESCENCE
RESOURCES-AT-A-GLANCE
Detailed Outline
Learning
Objectives
Instructor’s Resources
Test Bank
MyPsychLab Connection
Chapter Introduction pp. 265-266
PowerPoint Slides
1-4
MC 1
Sketchnote Video
Adolescence
Physical Changes pp. 266-272
Brain Development and Physical
Growth
Milestones of Puberty
Timing of Puberty
11.1
11.2
11.3
PowerPoint Slides
5-20
MC 2-25
FI 74–76
SA 89–91
ES 104–106
Adolescent Sexuality pp. 273-277
Sexual Behavior
Adolescent Pregnancy
11.4
11.5
PowerPoint Slides
20–37
MC 26-40
FI 77–81
SA 92–93
Watch
Today I Found Out: A Girl
Discusses Her Best Friend’s
Transsexual, p. 276
Adolescent Health pp. 277-282
Sensation Seeking
Drugs, Alcohol, and Tobacco
Eating Disorders
Depression and Suicide
11.7
11.8
11.9
11.10
Lecture Enhancer
Body Image and Eating
Disorders
PowerPoint Slides
38–45
MC 41-56
FI 82–84
SA 94–98
ES 109
Watch
Teen Alcoholism, p. 278
Anorexia Nervosa, p. 279
Depression, Reward Regions, and
the Brain: Erika Forbes, p. 281
Changes in Thinking and
Lecture Enhancer
MC 57-65
Watch
Transition to Secondary School
11.14
11.15
FI 86–88
SA 101-103
Schooling pp. 286-291
PowerPoint Slides
MC 66-73
CHAPTER OVERVIEW
Development in adolescence is marked by strides, as well as challenges. Along with physical maturity
comes new health risks. Advances in cognitive functioning enable teenagers to function almost as well as
adults. School experiences are critical to adolescent development.
There are two major growth spurts in the brain during the teenage years. An adolescent may grow three
to six inches a year for several years, then continue to add height and weight slowly until he or she
Sexual activity among teens has increased in recent decades in the United States, but many do not use
contraception consistently. Long-term consequences for teenaged mothers are generally negative,
although some girls are able to overcome the challenges. Teens who are homosexual or who are unsure
about their sexual orientation face many obstacles in the formation of an identity.
In Piaget’s fourth stage of cognitive development, the formal operational period, teenagers learn to reason
logically about abstract concepts. It is characterized by the ability to apply basic operations to ideas and
possibilities—systematic problem solving—in addition to actual objects. There is clear evidence of some
advanced forms of thinking in at least some adolescents, but formal operational thinking is not universal,
nor is it consistently used even by those who possess the ability. Adolescents process information faster,
LEARNING OBJECTIVES
After completing Chapter 11, students should be able to answer the following questions:
11.1 How do the brains and other body systems of adolescents differ from those of younger children?
11.2 What are the major milestones of puberty?
11.3 What are the consequences of early, “on time,” and late puberty for boys and girls?
11.4 What are the patterns of adolescent sexual behavior in the United States?
11.5 Which teenaged girls are most likely to get pregnant?
11.6 What are some causes that have been proposed to explain homosexuality?
11.7 How does sensation seeking affect risky behavior in adolescents?
11.8 What patterns of drug, alcohol, and tobacco use have been found among adolescents in the United
States?
11.9 What are the characteristics and causes of eating disorders?
KEY TERMS
ability goals (p. 287)
adolescence (p. 266)
anorexia nervosa (p. 279)
bulimia nervosa (p. 279)
formal operational stage (p. 282)
hypothetico-deductive reasoning (p. 283)
imaginary audience (p. 284)
menarche (p. 268)
personal fable (p. 284)
INTEGRATED CHAPTER TEACHING NOTES
PHYSICAL CHANGES (pp. 266-272)
Adolescence is a transitional period between childhood and adulthood. Physical changes occur during
adolescence, but momentous changes occur in other systems as well.
Brain Development and Physical Growth
LO 11.1 How do the brains and other body systems of adolescents differ from those of younger
children?
The Brain
There are two major brain growth spurts in the teenaged years:
▪ The first occurs between 13 and 15. The cerebral cortex becomes thicker, and the neuronal pathways
become more efficient. Additionally, more energy is produced and consumed by the brain during this
spurt than in the years that precede and follow it. These growth and energy spurts take place in the
parts of the brain that control spatial perception and motor functions. Consequently, by the mid-
teens, adolescents’ abilities in these areas far exceed those of school-aged children. Some
Discussion Launcher (Learning Objective 11.1, pp. 266-267)
Why is the development of executive processing skills important to adolescents?
▪ The second brain growth spurt begins around age 17 and continues into early adulthood. This time,
the frontal lobes of the cerebral cortex (the area that controls logic and planning) are the focus of
Discussion Launcher (Learning Objective 11.1, pp. 266-267)
What might be the result of a delay in the growth spurts in the brain? What could be some causes of such
a delay?
Other Body Systems
An adolescent may grow three to six inches a year for several years. After the growth spurt, teenagers
The shape and proportions of the adolescent’s body also go through a series of changes. During the
Discussion Launcher (Learning Objective 11.1, p. 267)
What might be some of the psychological issues involved with the awkwardness of this growth spurt?
Give examples.
Besides increasing in size, the skeletal system goes through other changes. In the elementary-school
years, the size and shape of the child’s jaw change when the permanent teeth come in. In adolescence,
both jaws grow forward and the forehead becomes more prominent.
Milestones of Puberty
LO 11.2 What are the major milestones of puberty?
Puberty is a collective term that encompasses all of the changes needed for reproductive maturity. It
begins when the pituitary gland triggers the release of hormones from other glands; thus, it is sometimes
called the master gland. The pituitary gland secretes two other hormones, the thyroid stimulating
hormone and the general growth hormone.
The most obvious changes of puberty are those associated with sexual maturity.
▪ Changes in primary sex characteristics include growth of the testes and penis in the male and the
ovaries, uterus, and vagina in the female.
Discussion Launcher (Learning Objective 11.2, p. 268)
What would be the effect of an interruption in the sequence of the stages, for example, a major illness?
Sexual Development in Girls
Menarche, the first menstruation, occurs two years after the beginning of other visible changes and is
succeeded only by the final stages of breast and pubic hair development. Among girls in industrialized
The Secular Trend
The timing of menarche changed dramatically between the mid-19th and the mid–20th centuries. In 1940,
Discussion Launcher (Learning Objective 11.2, p. 269)
Why would the increase in protein and fat intake affect the timing of puberty?
Sexual Development in Boys
In boys, as in girls, the peak of the growth spurt typically comes fairly late in the sequence of physical
development. On average, a boy completes stages 2, 3, and 4 of genital development and stages 2 and 3
Discussion Launcher (Learning Objective 11.2, p. 270)
What are some factors that might influence the variability in the timing of physical development?
The secular trend in pubertal development has been far less dramatic among boys than among girls.
Timing of Puberty
LO 11.3 What are the consequences of early, “on time,” and late puberty for boys and girls?
Although the order of physical developments in adolescence seems to be highly consistent, there is quite a
lot of individual variability. Researchers think that hereditary and behavioral factors work together to
control hormonal secretions in the bodies of individual teenagers, thereby controlling the timing of
puberty. Discrepancies between an adolescent’s expectation and what actually happens determine the
Classroom Activity (Learning Objective 11.3, p. 270)
In teams, create a list of cultural factors in the United States that might influence adolescents’ perception
of desirable body types. Discuss the lists with the entire class.
Research in the United States generally confirms these predictions.
▪ Girls who are early developers (who experience major body changes before age 11 or 12) show
consistently more negative body images, such as thinking of themselves as too fat. Such girls are also
Discussion Launcher (Learning Objective 11.3, pp. 209-271)
Do you remember whether you went through puberty very early, early, “on time,” or late? Do you think
that perception had any effect on your overall experience of adolescence?
Research also indicates that pubertal timing interacts with a number of other variables to produce both
positive and negative effects on adolescents’ development.
▪ Personality traits contribute to the effects of pubertal timing. Girls who experience early puberty and
who are high in the Big Five trait of openness to experience are more likely to be sexually active at an
early age than are girls who are early but who do not possess this trait.
▪ Parenting also moderates the effects of pubertal timing such that early-maturing boys and girls are
more likely to become involved in sexual activity and substance abuse if their parents are permissive.
Critical Thinking Question (learning Objectives 11.1-11.3, pp. 266-272)
Suppose you were asked to give a talk to parents about young teenagers’ need for sex-education and for
adult guidance with regard to romantic relationships. How would you integrate the information on brain
development with the discussion of the stages of puberty in your presentation?
ADOLESCENT SEXUALITY (pp. 273-277)
MyPsychLab Connections
Watch: Today I Found Out: A Girl Discusses Her Best Friend’s Teenage Pregnancy, p. 274
Watch: Gender Roles: Charlotte Anjelica, Transsexual, p. 276
Sexual Behavior
LO 11.4 What are the patterns of adolescent sexual behavior in the United States?
Prevalence of Sexual Behavior
Research findings indicate that boys are more sexually active and that the proportion of sexually
experienced teens increased across grades nine through twelve. Rates of sexual activity have declined
substantially over the past three decades. Sexual experiences vary across racial and ethnic groups.
Among currently sexually active students, there are also age and ethnic differences.
Although sexual activity among boys is somewhat correlated with the amount of testosterone in the
blood, social factors are much better predictors than hormones of teenagers who begin sexual activity
early.
▪ They live in poor neighborhoods in which young people are not well-monitored by adults.
Discussion Launcher (Learning Objective 11.4, pp. 272-273)
If you were a parent of an adolescent, how could you reduce the number of risk factors present in his or
her life?
Contraceptive Use
About 90% of high school students report having learned about sexually transmitted diseases in school.
Even when they are knowledgeable about STDs, many teens lack the assertiveness necessary to resist
sexual pressure from a romantic partner or to discuss condom use. Nevertheless, rates of condom use
have increased among teens, and today’s teens are less likely to use birth control pills than their
counterparts in earlier decades. Many developmentalists and public health advocates say that more
Discussion Launcher (Learning Objective 11.4, p. 273)
Conduct a debate regarding the different types of sex-education programs, including promoting
abstinence.
Adolescent Pregnancy
LO 11.5 Which teenaged girls are most likely to get pregnant?
The rate of teenaged pregnancy is higher in the United States than in any other Western industrialized
country. When the statistics are broken down by adolescent subgroup, teen pregnancy is far more
frequent among older adolescents and, in fact, is most likely to happen after a girl leaves high school.
Whether a girl becomes pregnant during her teenaged years depends on many of the same factors that
predict sexual activity in general.
▪ The younger a girl is when she becomes sexually active, the more likely she is to become pregnant.
Discussion Launcher (Learning Objective 11.5, p. 274)
List reasons why a girl’s peer rejection increases the likelihood of her becoming pregnant.
In contrast, the likelihood of pregnancy is lower among teenaged girls who do well in school and have
strong educational aspirations. Such girls are both less likely to be sexually active at an early age and
more likely to use contraception if they are sexually active. Girls who have good communication about
sex and contraception with their mothers are also less likely to get pregnant.
Feature Box Activity (Learning Objective 11.5, p. 275)
Developmental Science in the Clinic: Crisis Intervention for the Pregnant Teen
Sexual Minority Youth
LO 11.6 What are some causes that have been proposed to explain homosexuality?
The emergence of a physical attraction to members of the opposite sex, or heterosexuality, is one of the
Gay, Lesbian, and Bisexual Adolescents
Several twin studies show that when one identical twin is homosexual, the probability that the other twin
will also be homosexual is 50 to 60 percent. The concordance rate is only about 20 percent for fraternal
twins and only about 11 percent among pairs of biologically unrelated boys adopted into the same family.
While homosexual adolescents clearly face unique challenges, they share many of the same concerns as
their heterosexual peers.
▪ Both homosexual and heterosexual girls are more likely to be dissatisfied with their physical
Transgendered Teens
Transgendered teens and adults are those whose psychological gender is the opposite of their biological
sex. Out of fear of being stigmatized, most teens who suspect that they are transgendered keep their
Critical Thinking Question (Learning Objectives 11.4-11.6, pp. 273-277)
Look back at Bronfenbrenner’s ecological model of development in Chapter 2. Think of sexually
developing adolescents as being in the innermost circle, or the biological context, and explain how the
microsystem, exosystem, and macrosystem affect sexually active teens, pregnant adolescents, and sexual
minority youth.
ADOLESCENT HEALTH (pp. 277-282)
MyPsychLab Connections
Watch: Teenage Alcoholism, p. 278
Watch: Anorexia Nervosa, p. 279
Watch: Depression, Reward Regions, and the Brain, p. 281
Sensation Seeking
LO 11.7 How does sensation seeking affect risky behavior in adolescents?
Teenagers appear to have what many developmentalists describe as a heightened level of sensation
seeking, or a desire to experience increased levels of arousal, such as those that accompany fast driving or
the “highs” associated with drugs. Sensation seeking leads to recklessness, which, in turn leads to
markedly increased rates of accidents and injuries. Risky behaviors may be more common in adolescence
than during other periods because they help teenagers gain peer acceptance and establish autonomy with
Discussion Launcher (Learning Objective 11.7, 277)
Why do you suppose teens who experienced early rejection by peers and/or neglect at home are more
likely to show risky behaviors?
The messages conveyed in the popular media about sex, violence, and drug and alcohol use may influence
Drugs, Alcohol, and Tobacco
LO 11.8 What patterns of drug, alcohol, and tobacco use have been found among adolescents in
the United States?
Illicit drug use is far less common among teens in recent years than in past cohorts. Still, drug use among
Discussion Launcher (Learning Objective 11.8, p. 278)
List reasons why you believe marijuana and alcohol use are common among U.S. teens.
Teenagers who express the most interest in sensation seeking are those who are most likely to use drugs
and consume alcohol. Teens who are high sensation-seekers choose friends who are similar. Once such