Chapter 12: Physical and Cognitive Development in Adolescence McGraw-Hill 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
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
Median Ages at Menarche in Selected Northern European Countries and the United States from 1845 to 1969 Norway Finland Sweden U.K. U.S.A. Median age (years) at menarche 18 17 16 15 14 13 Fig. 12.1 12 1840 1860 1880 1900 1920 1940 1960 Year 1980
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
Hormone Levels by Sex and Pubertal Stage for Testosterone and Estradiol Testosterone (pg/ml) 500 400 300 200 100 Estradiol (pg/ml) 110 90 70 50 30 10 Boys Girls 0 0 1 2 3 4 5 0 Pubertal stage 1 2 3 4 5 Fig. 12.2
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
Males Females Onset (average) Completion (average) Normal Range and Average Development of Sexual Characteristics in Males and Females Fig. 12.4 8 9 10 11 12 13 14 15 16 17 18 Age (years) Height spurt Penile growth Menarche Testicular growth Breast growth Growth of pubic hair
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
Early- and Late-Maturing Adolescent Girls Perceptions of Body Image in Early and Late Adolescence +.30 +.20 Early development Late development Body Image Score +.10 Mean -.10 -.20 -.30 Grade 6 Grade 10 Fig. 12.5
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
Cross-Cultural Comparisons of Adolescent Pregnancy Rates 80 60 40 U.S. England and Wales Canada France Sweden 20 0 Fig. 12.6 1970 1975 1980 1985 1990 1995 2000 Year
What happens to the adolescent brain? Spurts occur in the brain s electrical activity that may signal changes in cognitive development Some of the most recent discoveries regarding areas of the brain involved emotions and information-processing
Adolescent Problems and Health
What can be said about substance use and abuse among adolescents? 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
60 Trends in Drug Use by U.S. Eighth-, Tenth-, and Twelfth-Grade Students 40 12th grade 10th grade 20 8th grade 0 1975 1979 1983 1987 1991 1995 1999 2003 1977 1981 1985 1989 1993 1997 2001 Percentage of students who reported illicit drug use in past 12 months Year Fig. 12.8
Young Adolescents Reports of Use in the Family Matters Program 90 Figs. 12.9 and 12.10 Control group Experimental group Percentage Reporting Use in their Lifetime of: Alcohol Cigarette smoking 85 80 75 70 65 60 55 50 Baseline 3 mos 1 yr Baseline 3 mos 1 yr Initial reporting and 1st & 2nd follow-up 60 55 50 45 40 35 30 25 20
Families are important when adolescent substance abuse and negative consequences are evident 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, middleand upper-income families Stress results from not achieving high expectations Weight becomes something they can control
The Increase in Being Overweight in Adolescence from 1968 to 1999 in the United States Percentage overweight adolescents, 12-19 years of age 15 10 5 1966-1970 1971-1974 1976-1980 1988-1994 1999 Year Fig. 12.11
Adolescent health is of great importance Many factors linked to poor health habits and early death in adulthood begin in adolescence Cross-culturally, U.S. adolescents exercised less and ate more junk food Early formation of healthy behavior patterns has Immediate benefits Prevents or delays major causes of premature disability or death
Nutrition, exercise, and adolescent sleep patterns have physiological and psychological effects At home During school In social interactions Leading causes of adolescent death Accidents most are motor vehicle related Homicide second leading cause of death Suicide rate has tripled since 1950s
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 Assimilation dominates development of thought In later adolescence, accommodation returns to thinking and information-processing
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
Adolescence is a time of increased decision-making Situations are examined from multiple perspectives, and consequences anticipated A strategy for improving adolescent decisionmaking 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
Schools
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
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
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
Trends in High School Dropout Rates 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 Fig. 12.12
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
The End