1. Physical and Cognitive Development in Adolescence CHAPTER 9

2. The Nature of Adolescence Adolescence is a transitional period with continuity and discontinuity with childhood Not just a time of rebellion, crisis, pathology, and deviance More accurately, it is of a time of evaluation, decision making, commitment, finding a place in the world Ethnic, cultural, gender, socioeconomic, age, and lifestyle differences influence the actual life trajectory of every adolescent

3. The Nature of Adolescence Adolescents are exposed to complex options through the media They face the temptations of drug use and sexual activity Too many adolescents are not provided with adequate opportunities and support to become competent adults

4. Puberty Puberty is not the same as adolescence most important marker of the beginning of adolescence puberty ends long before adolescence does Puberty -- period of rapid physical maturation involving hormonal and bodily changes Puberty is not a single, sudden event the most noticeable changes are signs of sexual maturation and increases in height and weight Primary sex characteristics Secondary sex characteristics

5. Order of Male Pubertal Changes 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 Growth of facial hair

6. Order of Physical Changes in Females Breasts enlarge Pubic hair appears Hair appears in the armpits Height increases and hips become wider than shoulders Menarche, first menstruation, irregular and anovulatory Voice changes not comparable to males By the end, breasts become more fully rounded

7. Weight and Height and the Growth Spurt Girls tend to outweigh boys early in adolescence At the beginning of adolescence, girls tend to be as tall as or taller than boys of their age The mean age at the beginning of the growth spurt in girls is 9 and for boys, the mean age is 11

9. Hormonal Changes Hormones -- powerful chemical substances secreted by the endocrine glands and carried through the body by the bloodstream Puberty is an interaction of the hypothalamus, the pituitary gland, and the gonads Gonads -- the testes and ovaries -- are particularly important

10. Hormones Testosterone -- hormone associated in boys with the development of genitals, an increase in height, and a change in voice Estradiol is a type of estrogen in girls it is associated with breast, uterine, and skeletal development Testosterone and estradiol are present in the hormonal makeup of both boys and girls The hormone-behavior link is complex Direct effects on emotions Indirect effects on emotions

11. Timing and Variations in Puberty The timing of puberty Sex, genes, and weight Menarche Spermarche The average age of menarche has declined significantly since the mid-19th century Basic genetic program for puberty is wired into the species nutrition, health, and other environmental factors also affect puberty’s timing and makeup Average age for the pubertal sequence to begin is between 10 to 13.5 for boys and 9 to 15 for girls Stress Too early – too late

12. Early and Late Maturation Adolescents who mature earlier or later than their peers perceive themselves differently Early maturation in girls increases vulnerability to problems more likely to smoke, drink, be depressed, have an eating disorder, struggle for earlier independence from their parents, have older friends, date, and earlier sexual experiences

13. Body Image Adolescents are preoccupied with their bodies and develop images of what their bodies are like Girls are less happy with their bodies and have more negative body images than boys throughout puberty Boys become more satisfied as they move through puberty, probably because their muscle mass increases (Bearman & others, 2006)

14. Brain Development Adolescents’ brains undergo significant structural changes corpus callosum -- thickens and this improves ability to process information prefrontal cortex doesn’t finish maturing until 18 to 25 years of age or later amygdala -- the seat of emotions such as anger -- matures earlier than the prefrontal cortex

15. Adolescent Sexuality A time of sexual curiosity, exploration and experimentation, of sexual fantasies and realities, of incorporating sexuality into one’s identity

16. Developing a Sexual Identity Involves learning to manage sexual feelings (such as sexual arousal and attraction) and developing new forms of intimacy Learning skills to regulate sexual behavior to avoid undesirable consequences Sexual identity involves activities, interests, styles of behavior, and an indication of sexual orientation -- whether an individual has same-sex or other-sex attractions (Buzwell & Rosenthal, 1996)

17. The Timing of Adolescent Sexual Behaviors The timing of sexual initiation varies by country, gender, or socioeconomic characteristics Many early adolescents are not emotionally prepared to handle sexual experiences Early sexual activity is linked with risky behaviors such as drug use, delinquency, and school-related problems Low parental monitoring was linked with early initiation of sexual activity

18. Contraceptive Use Two kinds of risks accompany sexual activity: Unintended, unwanted pregnancy Sexually transmitted infections Both can be reduced significantly with contraception use Many sexually active adolescents still do not use contraceptives, or they use them inconsistently Younger adolescents are less likely to take contraceptive precautions

19. Sexually Transmitted Infections Sexually transmitted infections (STIs) -- infections contracted primarily through sexual contact, including oral-genital and anal-genital contact annually, more than 3 million American adolescents about one-fourth of those who are sexually experienced (Centers for Disease Control and Prevention, 2008)

20. Adolescent Pregnancy United States has one of the highest adolescent pregnancy and childbearing rates in the industrialized world; however, recent declines are noted Reasons for these recent declines include increased contraceptive use and fear of sexually transmitted infections such as AIDS

21. Risks of Becoming Pregnant as an Adolescent Health risks for both the baby and the mother Infants are more likely to have low birth weight Infants have more neurological problems and childhood illness Adolescent mothers often drop out of school Even if they resume their education, they generally never catch up economically

22. Characteristics Adolescent mothers are more likely to come from low-SES backgrounds Many were not good students before they became pregnant Some adolescent mothers do well in school and have positive outcomes All adolescents can benefit from age-appropriate family-life education

23. Issues in Adolescent Health Many of the behaviors that are linked to poor health habits and early death in adults begin during adolescence Early formation of healthy behavior patterns, such as regular exercise and a preference for foods low in fat and cholesterol has immediate health benefits helps in adulthood to delay or prevent disability and mortality

24. Nutrition and Exercise The percentage of overweight teens in the United States increased from the early 1990s through 2004 Compared to adolescents in 28 countries, U.S. and British adolescents ate more fried food and less fruits and vegetables U.S. boys and girls become less active as they reach and progress through adolescence

25. Nutrition and Exercise Adolescent boys are more likely to engage in moderate to vigorous exercise than were girls Exercise is linked to a number of positive physical outcomes Lower weight, reduced triglyceride levels, lower blood pressure, a lower incidence of type II diabetes, lower drug use

26. Sleep Patterns 45 percent of adolescents studied got inadequate sleep on school nights (fewer than 8 hours) inadequate sleep resulted in feeling more tired or sleepy, cranky and irritable, falling asleep in school, being in a depressed mood, and drinking caffeinated beverages adolescents’ biological clocks undergo a shift as they get older; this seems related to a delay in the nightly release of the sleep-inducing hormone melatonin (National Sleep Foundation, 2006)

27. Leading Causes of Death in Adolescence The three leading causes of death in adolescence are accidents, homicide, and suicide More than half of deaths for ages 15 to 24 are due to unintentional injuries; three-fourths involve motor vehicles Homicide is the second-leading cause of death, especially among African-American males The adolescent suicide rate has tripled since the 1950s

28. Substance Use and Abuse Proportions of U.S. students who used any illicit drug declined in the late 1990s and first years of the 21st century The United States still has one of the highest rates of adolescent drug use of any industrialized nation Early onset of drinking linked to increased risk of heavy drinking in middle age Parents play a role in preventing drug abuse Peers also influence whether adolescents become substance abusers Gateway drugs Two explanations (Johnston & others, 2010)

29. Anorexia Nervosa Anorexia nervosa -- eating disorder that involves the relentless pursuit of thinness through starvation Three main characteristics of anorexia nervosa are: weighing less than 85 percent of what is considered normal for a person’s age and height having an intense fear of gaining weight having a distorted image of one’s body shape

30. Bulimia Nervosa Bulimia nervosa -- eating disorder in which the individual consistently follows a binge-and- purge pattern Bulimics go on an eating binge and then purge by self-inducing vomiting or using laxatives Bulimics are preoccupied with food, have a strong fear of becoming overweight, and are depressed or anxious

31. The Formal Operational Stage According to Piaget, the fourth and final stage of cognitive development, the formal operational stage, begins in adolescence Formal operational thought is more abstract and logical; full of idealism and possibilities Hypothetical-deductive reasoning involves creating a hypothesis and deducing its implications

32. Adolescent Egocentrism Adolescent egocentrism is the heightened self- consciousness of adolescents David Elkind (1976) cited two key components: imaginary audience personal fable Adolescents also often show a sense of invincibility or invulnerability

33. Information Processing Executive functioning involves higher-order cognitive activities such as reasoning, making decisions, monitoring thinking critically, and monitoring one’s cognitive progress Improvements in executive functioning permit: more effective learning making decisions and engaging in critical thinking

34. Decision Making and Critical Thinking 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 The social context plays a role in adolescent decision making Cognitive changes that allow for improved critical thinking are: Increased speed, automaticity, and capacity of information processing More benefits of content knowledge Increased ability to construct new combinations of knowledge Greater range and more spontaneous use of strategies or procedures for applying or obtaining knowledge

35. School Issues Top-dog phenomenon -- moving from being the oldest, biggest, and most powerful to being the youngest, smallest, and least powerful students (“The usual dip”) Consequence of moving from middle to high school U.S. high school dropout rates have declined Service learning -- form of education that promotes social responsibility and service to the community