Life-Span Development Chapter 11: Physical and Cognitive Development in Adolescence

1. Life-Span Development Chapter 11: Physical and Cognitive Development in Adolescence McGraw-Hill © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.

2. The Nature of Adolescence What physical changes occur in adolescence? • Pubertal with rapid physical changes involving hormones • Menarche is a girl’s first menstruation • Puberty is also triggered by body mass • Genetic factors are involved in puberty • Puberty involves the interaction of the hypothalamus, pituitary gland, and gonads • The onset of puberty varies among individuals

3. Norway 18 Finland Sweden 17 U.K. 16 U.S.A. 15 Median age (years) at menarche 14 13 12 1840 1860 1880 1900 1920 1940 1960 1980 Year Median Ages at Menarche in Selected Northern European Countries and the United States from 1845 to 1969 Fig. 12.1

4. Most noticeable physical changes include • Pubic hair growth • Facial and chest hair growth in males • Breast growth in females • Increased height and weight • Sexual maturity • Adolescent sexuality is initiated by • First ejaculation, voice change, penis elongation, and testes development in males • Highly irregular menstrual cycles, rounding of breasts, and widening of hips in females

5. Boys Testosterone (pg/ml) Estradiol (pg/ml) Girls 500 110 400 90 70 300 50 200 30 100 10 0 0 1 2 3 4 5 0 1 2 3 4 5 Pubertal stage Hormone Levels by Sex and Pubertal Stage for Testosterone and Estradiol Fig. 12.2

6. Early onset of puberty can create risks for females • Depression • Eating disorders • Use of alcohol, drugs, and/or tobacco • Earlier dating and sexual involvement with males • Possible lower educational attainment • Pubertal changes have a strong effect on the adolescent’s body image, dating interest, and sexual behavior

7. +.30 +.20 +.10 Body Image Score Mean -.10 -.20 -.30 Grade 6 Grade 10 Early- and Late-Maturing Adolescent Girls’ Perceptions of Body Image in Early and Late Adolescence Early development Late development Fig. 12.5

8. Height spurt Penile growth Menarche Testicular growth Breast growth Growth of pubic hair 8 9 10 11 12 13 14 15 16 17 18 Normal Range and Average Development of Sexual Characteristics in Males and Females Males Females Onset (average) Completion (average) Age (years) Fig. 12.4

9. Adolescent Sexuality • Adolescent sexuality is a time of exploration, experimentation, and sexual fantasies • Adolescence is a bridge between the asexual child and sexual adulthood – reaction of each society may vary • Television and other media contribute to the sexual culture • Developing a sexual identity involves • Sexual behavior • Indication of sexual orientation

10. Percentages of sexually active young adolescents in the United States vary greatly • Male, African American, and inner-city adolescents report being the most sexually active • Early sexual activity is linked to other risky behaviors and to contracting STIs • Self-regulation and parent–child relationships are two important factors in sexual risk-taking • Adolescents are increasing their use of contraceptives • Cross-culturally, the United States still has one of the highest adolescent pregnancy and birth rates

11. 80 U.S. England and Wales 60 Canada France 40 Sweden 20 0 1970 1975 1980 1985 1990 1995 2000 Year Cross-Cultural Comparisons of Adolescent Pregnancy Rates Fig. 12.6

12. The Adolescent Brain • Spurts in the brain’s electrical activity at 9, 12, 15 and 18 to 20 may signal changes in cognitive development • Neural activity using dopamine increases. • Synaptic pruning continues. • Some of the most recent discoveries regarding areas of the brain involved emotions and information-processing • The amygdala, which is involved in processing information about emotion, develops before the frontal lobes.

13. Adolescent Substance Abuse • Monitoring the Future Study began in 1975 • 1960s and 1970s were a time of marked increases in the use of illicit drugs and social unrest • Annual studies since 1975 show that adolescent drug use among U.S. secondary school students • Declined in the 1980s • Began to increase in the 1990s • Declined among high school seniors after 1998 • Explanations for declining rates vary • Parents and peers can influence usage attitudes

14. Adolescent Alcohol and Nictotine • The percentage of 8th, 10th and 12th graders reporting that they had used alcohol in the past 30 days dropped from 26 to 21% from 96 to 2003, and the percentage of students reporting binge drinking dropped from 41 to 31%. The percentage of high school cigarette smokers dropped from 36% in 97 to 24% in 2003. • Risk factors for smoking include: having a friend who smoked, a weak academic orientation and low parental support.

15. 60 40 20 0 1975 1979 1983 1987 1991 1995 1999 2003 1977 1981 1985 1989 1993 1997 2001 Year Percentage of students who reported illicit drug use in past 12 months Trends in Drug Use by U.S. Eighth-, Tenth-, and Twelfth-Grade Students 12th grade 10th grade 8th grade Fig. 12.8

16. Control group Experimental group Percentage Reporting Use in their Lifetime of: Alcohol Cigarette smoking 90 60 85 55 80 50 75 45 70 40 65 35 60 30 55 25 50 20 Baseline Baseline 3 mos 1 yr 3 mos 1 yr Young Adolescents’ Reports of Use in the Family Matters Program Initial reporting and 1st & 2nd follow-up Figs. 12.9 and 12.10

17. Eating Disorders • Eating problems and disorders are increasingly common in adolescence – most notably, anorexia nervosa and bulimia nervosa • Since the 1960s, a higher percentage of adolescents have become overweight • Most anorexics are White adolescents or young adult females from well-educated, middle- and upper-income families • Stress results from not achieving high expectations • Weight becomes something they can control

18. Anorexia Nervosa • Refusal to maintain body weight above the minimal normal weight for individual’s height and weight. • Body weight 15% or more below normal • Intense fear of gaining weight • Distortion of body image • Amenorrhea (cessation of menstruation) • Secondary symptoms: slow heart rate, low blood pressure, low body temperature • Often associated with depression, obsessions and compulsions • 10X more common in males.

19. Bulimia Nervosa • Eating binges and inappropriate compensatory measures to prevent weight gain (at least 2X/week for 3 months). • Attempts to compensate for binging may include purging, vomiting, fasting, laxatives, enemas or exercise. • Preoccupation with food and intense fear of gaining weight. • Binging is not the result of a need for food • Often associated with depression and obsessive-compulsive symptoms. • Generally of normal weight.

20. Risk Factors for Eating Disorders • Feeling negatively about your body early in adolescence • Having negative relationships with parents • Being sexually active and in pubertal transition. • Being highly motivated to look like same-sex media figures. • Watching 4+ hours of tv per day • Being from a well-educated, middle or upper income family.

21. Adolescent Health • Adolescent health is of great importance – • Many factors linked to poor health habits and early death in adulthood begin in adolescence • U.S. adolescents exercised less and ate more junk food than adolescents in 28 countries. • Early formation of healthy behavior patterns has • Immediate benefits • Prevents or delays major causes of premature disability or death

22. 15 10 5 1966-1970 1971-1974 1976-1980 1988-1994 1999 Year The Increase in Being Overweight in Adolescence from 1968 to 1999 in the United States Percentage overweight adolescents, 12-19 years of age Fig. 12.11

23. Nutrition, exercise, and adolescent sleep patterns have physiological and psychological effects • At home • During school • In social interactions • Most adolescents do not get enough sleep and sleep deprivation seems associated with lower self-esteem and higher incidence of depression. • Leading causes of adolescent death • Accidents (account for ½ of teen deaths) – most are motor vehicle related and driver has a blood alcohol level of .1 or higher in ½ of fatal car accidents. • Homicide – second leading cause of death • Suicide – rate has tripled since 1950s

24. Adolescent Cognition • Adolescent cognition shows greater abstract quality in ability to • Solve problems by verbal means alone • Create make-believe or purely hypothetical situations • Engage in extended speculation and test solutions systematically • Engage in “hypothetico-deductive reasoning,” which involves formulating and testing possible solutions to problems. • Assimilation dominates development of thought • In later adolescence, accommodation returns to thinking and information-processing

25. Adolescent egocentrism involves two types of social thinking: imaginary audience and personal fable • Adolescents have a sense of uniqueness and invincibility • Invincibility attitudes are likely to be associated with reckless behavior such as • Drug use • Suicide • Having unprotected sex

26. Adolescence is a time of increased decision-making • Situations are examined from multiple perspectives, and consequences anticipated • A strategy for improving adolescent decision-making includes parental involvement • Cognitive changes that improve critical thinking include • Increased speed of information-processing • Wider range of knowledge in variety of domains • Increased ability to construct new knowledge • Having more strategies to apply knowledge

27. The transition from elementary to middle or junior high school is of interest because • It can be stressful • It occurs at a time when family–child relationships change • Puberty and concerns about body image accompany changes in social cognition • A more impersonal school structure is entered • There is increased responsibility and independence • The “top-dog phenomenon” is experienced • Creating effective and positive environments for student learning is needed

28. Recommendations for effective schools include • Develop smaller communities that lessen impersonality of middle schools • Lower student–counselor ratios to 10-to-1 • Involve parents and community leaders • Develop curricula that produce better students • Integrate several disciplines in a flexible curriculum • Have more student health and fitness programs

29. U.S. high school education is of concern because of these facts: • Some students graduate with inadequate skills • Unskilled students go into college remedial classes • Dropouts lack adequate workplace skills • Dropout rates have declined over last 50 years • Dropout rates are highest among minorities • Students drop out of school for many reasons

30. Latino African American Total White 40 35 30 25 20 15 10 5 0 1972 1976 1980 1984 1988 1992 1996 2000 Percentage of 16- to 24-year-olds who have dropped out of school Trends in High School Dropout Rates Fig. 12.12

31. High schools for the future need to promote • More awareness of knowledge and skills needed by students upon graduation • Higher expectations for student achievement • Strong, positive adult role models • Higher-quality work experiences • More coordination and communication among all grade levels • More student service learning experiences