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Developmental Psychology Unit 7: Adolescence

Adolescence brings puberty, a reorganizing brain, abstract thought and the search for identity. This unit covers physical and brain changes, formal operations, identity formation, moral reasoning, relationships and common risks.

Covers: Puberty and its timing, The adolescent brain and risk-taking, Formal operations and adolescent egocentrism, Identity development, Moral reasoning: Kohlberg and Gilligan, Family and peer relationships, Adolescent risks and problems

Study guide

Puberty is triggered by hormones from the hypothalamus, pituitary gland and gonads. Girls typically begin earlier, with breast budding around 10 and menarche (first menstruation) around 12 to 13; boys typically begin around 11 or 12, with spermarche (first ejaculation) around 13. The growth spurt peaks about two years earlier in girls than in boys. Primary sex characteristics are the reproductive organs; secondary sex characteristics include breasts, body hair and a deeper voice. The secular trend is the earlier onset of puberty over the past century, linked to better nutrition and health. Timing matters: early-maturing girls face higher risks of depression, substance use and older peers, while early-maturing boys often gain status but may also show more risk-taking. Late-maturing boys may feel less confident.

The adolescent brain changes dramatically. The limbic system, which drives reward-seeking and emotional reactions, becomes highly responsive at puberty, while the prefrontal cortex, which supports planning and impulse control, keeps maturing into the mid-20s through pruning and myelination. Laurence Steinberg's dual-systems model explains teen risk-taking as a gap between an early-maturing reward system and a slower control system. Risk-taking rises especially when peers are present; in Steinberg's driving-game studies, teens took more risks when friends watched, while adults did not. Teens also experience a shift in circadian rhythm toward later sleep times, so early school start times often cause sleep deprivation. Many teens need about 8 to 10 hours of sleep but get closer to 7.

Piaget's formal operational stage begins around 11 or 12. Teens can now reason abstractly and hypothetically and use hypothetico-deductive reasoning: generating hypotheses and testing them systematically. In Piaget's pendulum problem, formal thinkers vary one factor at a time (string length, weight, drop height) to find that only length matters. Not every adult uses formal operations consistently, and schooling and expertise affect it. David Elkind described adolescent egocentrism with two parts. The imaginary audience is the belief that everyone is watching and judging, which explains intense self-consciousness. The personal fable is the belief that one's experiences are unique and that one is invulnerable, which may contribute to risk-taking. Both tend to fade by late adolescence.

Erikson saw identity versus role confusion as the central crisis of adolescence. James Marcia expanded this into four identity statuses defined by exploration (crisis) and commitment. Identity diffusion means neither exploring nor committing; foreclosure means committing without exploring, often adopting parents' values; moratorium means actively exploring without commitment; and identity achievement means committing after exploring. Statuses can change, and many people are in different statuses in different areas, such as career and religion. Jean Phinney described ethnic identity development, and a strong, positive ethnic identity tends to support well-being. On moral reasoning, Carol Gilligan argued that Kohlberg's justice-based stages undervalued an ethic of care, focused on relationships and responsibility, which she linked to many women's moral reasoning.

Relationships shift in adolescence. Parent-teen conflict, usually over everyday issues such as chores and curfews, rises in early adolescence and declines later, and most teens stay close to parents. Teens seek more autonomy, and authoritative parenting with monitoring still predicts the best outcomes. Peers become central: cliques are small friendship groups, while crowds are larger reputation-based groups such as 'jocks' or 'brains'. Conformity to peer pressure peaks in early-to-middle adolescence. Risks include depression, which becomes about twice as common in girls as in boys after puberty; eating disorders such as anorexia and bulimia; and substance use. Terrie Moffitt distinguished adolescence-limited delinquency, which is common and fades in adulthood, from life-course-persistent antisocial behavior, which begins early and is linked to childhood problems.

Key ideas

• Puberty begins about two years earlier in girls than boys, and early maturation carries special risks for girls.
• The dual-systems model explains teen risk-taking as a gap between an early-maturing reward system and a slower prefrontal control system.
• Formal operational thought allows abstract, hypothetical and systematic reasoning.
• The imaginary audience and personal fable are two forms of adolescent egocentrism described by Elkind.
• Marcia's identity statuses are defined by whether a person has explored and whether they have committed.
• Gilligan argued that Kohlberg's justice focus overlooks an ethic of care.
• Moffitt separated common adolescence-limited delinquency from rarer life-course-persistent antisocial behavior.

Formulas and rules

Common mistakes

• Confusing foreclosure (committed without exploring) with moratorium (exploring without committing).
• Mixing up the imaginary audience (everyone is watching) with the personal fable (I am unique and invulnerable).
• Assuming teens take risks because they cannot understand risk; they often know the risks but are swayed by reward and peers.
• Thinking early maturation is equally risky for boys and girls.
• Assuming parent-teen conflict usually means the relationship has broken down.

Before the test, make sure you can

• Describe the hormonal and physical changes of puberty and typical sex differences in timing.
• Explain the effects of early and late pubertal timing.
• Use the dual-systems model to explain teen risk-taking and peer effects.
• Identify formal operational reasoning and adolescent egocentrism from examples.
• Classify a person into one of Marcia's identity statuses.
• Compare Kohlberg's justice orientation with Gilligan's ethic of care.
• Describe changes in parent and peer relationships during adolescence.
• Distinguish adolescence-limited from life-course-persistent antisocial behavior.

Words to know

Menarche

A girl's first menstrual period, usually around ages 12-13.

Spermarche

A boy's first ejaculation, usually around age 13.

Secular trend

The trend toward earlier puberty and greater height across generations.

Dual-systems model

The view that teen risk-taking results from a reward system that matures before the prefrontal control system.

Formal operational stage

Piaget's final stage, beginning around 11-12, marked by abstract and hypothetical reasoning.

Hypothetico-deductive reasoning

Forming hypotheses and testing them systematically to reach a conclusion.

Imaginary audience

An adolescent's belief that others are constantly watching and judging them.

Personal fable

An adolescent's belief that their experiences are unique and that they are invulnerable.

Identity diffusion

Marcia's status of neither exploring options nor making commitments.

Identity foreclosure

Marcia's status of committing to an identity without exploring alternatives.

Moratorium

Marcia's status of actively exploring identity options without yet committing.

Identity achievement

Marcia's status of committing to an identity after exploring options.

Ethnic identity

A sense of belonging to an ethnic group and the meaning one attaches to it.

Ethic of care

Gilligan's moral orientation centered on relationships, compassion and responsibility to others.

Crowd

A large, reputation-based peer group, such as 'athletes' or 'brains'.

Clique

A small group of close friends who spend time together.

Adolescence-limited delinquency

Antisocial behavior that begins in adolescence and usually stops in early adulthood.

Life-course-persistent antisocial behavior

Antisocial behavior that begins in childhood and continues into adulthood.

Sample practice questions

30 more questions like these, from level 1 to 5, are in the practice set.