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

Year Median age (years) at menarche Finland Sweden U.S.A. Norway U.K. Fig Median Ages at Menarche in Selected Northern European Countries and the United States from 1845 to 1969

–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

Fig Testosterone (pg/ml) Estradiol (pg/ml) Pubertal stage Girls Boys Hormone Levels by Sex and Pubertal Stage for Testosterone and Estradiol

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

Fig Age (years) Height spurt Menarche Penile growth Breast growth Testicular growth Growth of pubic hair Completion (average) Females Onset (average) Males Normal Range and Average Development of Sexual Characteristics in Males and Females

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

Fig Late development Early development Early- and Late-Maturing Adolescent Girls’ Perceptions of Body Image in Early and Late Adolescence Mean Body Image Score Grade 10Grade 6

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

Fig Cross-Cultural Comparisons of Adolescent Pregnancy Rates England and Wales Canada France Sweden U.S. 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

Trends in Drug Use by U.S. Eighth-, Tenth-, and Twelfth-Grade Students Fig Percentage of students who reported illicit drug use in past 12 months Year 12th grade 10th grade 8th grade

Figs and Experimental groupControl group Baseline 1 yr3 mos Baseline 1 yr3 mos Percentage Reporting Use in their Lifetime of: Cigarette smokingAlcohol Young Adolescents’ Reports of Use in the Family Matters Program Initial reporting and 1st & 2nd follow-up

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, middle- and upper-income families –Stress results from not achieving high expectations –Weight becomes something they can control

Fig Year The Increase in Being Overweight in Adolescence from 1968 to 1999 in the United States Percentage overweight adolescents, years of age

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 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

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

Fig Trends in High School Dropout Rates

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