Infants Children and Adolescents Eighth Edition Chapter 14

Infants, Children, and Adolescents Eighth Edition Chapter 14 Physical Development in Adolescence Copyright © 2016 Laura E. Berk. All Rights Reserved.

Learning Objectives (1 of 3) • • • 14. 1 How have conceptions of adolescence changed over the past century? 14. 2 Describe body growth, motor performance, and sexual maturation during puberty. 14. 3 What factors influence the timing of puberty? 14. 4 Describe brain development and changes in the organization of sleep and wakefulness during adolescence. 14. 5 Explain adolescents’ reactions to the physical changes of puberty. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Learning Objectives (2 of 3) • • • 14. 6 Describe the impact of pubertal timing on adolescent adjustment, noting sex differences. 14. 7 Describe nutritional needs, and cite factors related to eating disorders in adolescence. 14. 8 Cite common unintentional injuries in adolescence. 14. 9 Discuss social and cultural influences on adolescent sexual attitudes and behavior. 14. 10 Describe factors involved in the development of homosexuality. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Learning Objectives (3 of 3) • • 14. 11 Discuss factors related to sexually transmitted infections and teenage pregnancy and parenthood. 14. 12 What personal and social factors are related to adolescent substance use and abuse? Copyright © 2016 Laura E. Berk. All Rights Reserved.

Conceptions of Adolescence • Biological perspective: – Puberty: period of storm and stress – Freud’s genital stage: reawakening of sexual impulses • Social perspective: – Role of social and cultural influences – Wide variability in adolescent adjustment • Balanced point of view: – Biological, psychological, and social influences – Cultural variation in length and demands of adolescence Copyright © 2016 Laura E. Berk. All Rights Reserved.

Phases of Adolescence Early Middle Late 11– 12 to 14 years 14 to 16 years 16 to 18 years Copyright © 2016 Laura E. Berk. All Rights Reserved. Rapid pubertal change Pubertal changes nearly complete Full adult appearance, assumption of adult roles

Hormonal Changes in Puberty • Release of growth hormone (GH) and thyroxine • Adrenarche: release of adrenal androgens • Estrogens – contribute to girls’ height spurt, development of female sex characteristics, regulation of menstrual cycle. – combine with androgens to stimulate gains in bone density. • Testosterone – is released by boys’ maturing testes. – leads to muscle growth, body and facial hair, other male sex characteristics; also contribute to gains in body size. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Hormonal Influences on the Body at Puberty Figure 14. 1 Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sex Differences in Body Growth in Adolescence Growth spurt Proportions Muscle–fat makeup Boys Girls Starts age 12½ Starts age 10 Shoulders broaden Hips broaden Longer legs Gain more muscle Gain more fat Heart, lung capacity increase Copyright © 2016 Laura E. Berk. All Rights Reserved.

Motor Development and Physical Activity • Improvement in gross-motor development with puberty: – Girls: slow, gradual gains – Boys: dramatic spurt in strength, speed, endurance • Boys’ use of performance-enhancing drugs: creatine, anabolic steroids, androstenedione • Decline in physical education and daily freetime physical activity with age Copyright © 2016 Laura E. Berk. All Rights Reserved.

Decline in Regular Free-Time Daily Physical Activity in Adolescence Figure 14. 3 (Based on Wall et al. , 2011. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sexual Maturation • Primary sexual characteristics: – Maturation of reproductive organs – Girls: menarche – Boys: spermarche • Secondary sexual characteristics: – – Girls: breasts Boys: facial hair, voice change Both sexes: underarm, pubic hair Other visible parts of the body that signal sexual maturity Copyright © 2016 Laura E. Berk. All Rights Reserved.

Individual Differences in Pubertal Growth Timing of pubertal changes is influenced by • heredity. • nutrition and exercise. • geographical location. • SES and ethnic group. • early family experiences. • secular trend toward earlier pubertal timing. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Secular Trend in Age at Menarche Figure 14. 4 (From K. Sørensen et al. , 2012. “Recent Secular Trends in Pubertal Timing: Implications for Evaluation and Diagnosis of Precocious Puberty, ” Hormone Research in Pædiatrics, 77, p. 139. Copyright © 2012 Karger Publishers, Basel, Switzerland. Reprinted by permission. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Brain Development in Adolescence • White matter increases, gray matter declines: – Pruning of unused synapses continues. – Myelination accelerates, strengthening connections among brain regions. – Prefrontal cortex becomes more effective “executive. ” • Neurons become more sensitive to excitatory neurotransmitters. • Changes in emotional/social network outpace development of prefrontal cognitive-control network. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sleep Habits in Adolescence • Adolescents need almost as much sleep as they did in middle childhood: about 9 hours. • Teenagers go to bed later because of – biological changes. – evening social activities, use of screen media. • Sleep deprivation – affects performance on cognitive tasks. – may lead to anxiety and depressed mood. – is associated with high-risk behaviors. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Reactions to Pubertal Changes • Pubertal events affect self-image, mood, interaction with parents and peers. • Girls’ responses to menarche depend on – prior knowledge and family support. – cultural attitudes toward puberty and sexuality. • Tribal and village societies may celebrate puberty with initiation ceremony. • Western adolescents – have no widely accepted marker of maturity. – gain partial adult status at many different ages. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Emotional and Social Responses to Puberty • Adolescent moodiness – is modestly linked to higher hormone levels. – is linked to negative life events. • Moods are less stable in younger than older adolescents. • Parent–child relationships: – Puberty is linked to rise in intensity of parent–child conflict. – Psychological distancing may be modern substitute for departure of the young from the family group. • Both generations benefit from warm family bonds throughout lifespan. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Consequences of Pubertal Timing Boys Earlymaturing Latematuring • • • Girls • Unpopular, withdrawn • Low confidence, negative body image • More involved in deviant behavior • Unpopular • Popular • Transient emotional • Sociable, lively difficulties until they catch • Positive body image up physically with peers Popular Confident, independent Positive body image Psychological distress Problem behaviors Copyright © 2016 Laura E. Berk. All Rights Reserved.

Reactions to Timing of Puberty: Role of Physical Attractiveness • Body image: – Strong predictor of self-esteem for both sexes – Cultural ideal of thin, long-legged female and tall, muscular male body • Fitting in with peers: – Preference for peers who are similar in physical maturity – Risks for early maturers in economically disadvantaged neighborhoods • Long-term consequences: – Greatest risks for early-maturing girls – Unfavorable peer pressures, adjustment problems Copyright © 2016 Laura E. Berk. All Rights Reserved.

Nutrition in Adolescence • Dramatic rise in nutritional requirements • Poor food choices in adolescence: – Skipping breakfast – Eating on the run – Consuming empty calories • Common deficiencies: iron, calcium, vitamins • Risks associated with special diets Copyright © 2016 Laura E. Berk. All Rights Reserved.

Eating Disorders: Anorexia Nervosa • Anorexia nervosa affects about 1% of North American and Western European teenage girls: – Boys account for 10– 15% of cases. – Incidence has increased sharply in past half-century. • Individual, family, and cultural factors contribute: – Abnormalities in brain neurotransmitters – Parent–adolescent interactions related to autonomy – Societal image of “thin is beautiful” • Treatment is difficult: – Most successful combines family therapy and medication. – Less than 50% recover fully. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Eating Disorders: Bulimia Nervosa and Binge-Eating Disorder • Bulimia nervosa affects 2– 4% of teenage girls: – Gay and bisexual boys are also vulnerable. – Most adolescents with bulimia lack self-control in many areas. – Feelings of guilt and depression are typical. • Binge-eating disorder affects 2– 3% of teenage girls and nearly 1 percent of boys – Equally prevalent among U. S. ethnic groups – Leads to weight gain and obesity • Treatment includes – support groups. – nutrition education and training in changing eating habits. – anti-anxiety, antidepressant, and appetite-control medication. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Injuries During Adolescence • Automobile accidents are leading killer of U. S. adolescents: – Accidents result from high speed, alcohol use, not wearing seat belts, using mobile devices. – Graduated licensing laws have led to decline in fatalities. • Firearms cause majority of other fatal injuries, especially in poverty-stricken inner-city neighborhoods. • Sports-related injuries are common: – Concussions are of particular concern, especially in football. – Safest athletic activities during adolescence are limitedcontact team sports. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Firearm Death Rates Among 15 - to 19 -Year-Olds Figure 14. 6 (Based on Canadian Paediatric Society, 2005; Centers for Disease Control and Prevention, 2014 d; Fingerhut & Christoffel, 2002. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Impact of Culture on Sexual Activity • Sexual attitudes in North America are relatively restrictive. • Parents provide limited information. • Children learn about sex from friends, books, magazines, movies, TV, Internet: – The Internet is an especially hazardous “sex educator. ” – In one study, 42% of 10 - to 17 -year-olds had viewed pornographic websites in past 12 months. – Of these, 66% said they encountered the images accidentally. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Parents and Teenagers (Don’t) Talk About Sex • Parent–child conversations about sex and contraception reduce sexual risk taking. • When parents dominate discussion, teenagers tend to withdraw. • Parents can communicate successfully with adolescents about sexual issues when they – – – foster open communication. use correct terms for body parts. use effective discussion techniques. reflect before speaking. keep the conversation going. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Adolescent Sexual Attitudes and Behavior • Sexual attitudes of U. S. adolescents and adults have become more liberal in past half-century. • Recently, adolescents have moved slightly toward more conservative beliefs. • Substantial percentage of teenagers are sexually active by ninth grade. • Mutually consensual sexual activity in a stable, caring relationship can be a positive, satisfying experience for older adolescents. • Casual sex leads to guilt and depression. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sexual Activity Among U. S. Adolescents Figure 14. 7 (Based on Kann et al. , 2014. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Characteristics of Adolescents Who Engage in Early Sexual Activity Personal Family Peer Educational • • • Early pubertal timing Tendency to violate norms Little or no religious involvement Single-parent or stepfamily homes Large family size Weak parental monitoring Disrupted parent–child communication Sexually active friends and older siblings Poor school performance Low educational aspirations Copyright © 2016 Laura E. Berk. All Rights Reserved.

Adolescent Contraceptive Use • Adolescent contraceptive use has increased in recent years. • However, about 18% of sexually active U. S. teens do not use contraception consistently. • Reasons for not using contraception include – difficulties with planning and self-regulation. – lack of communication with parents or medical personnel. – lack of realistic expectations about impact of early parenthood. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Contraceptive Use by Sexually Active U. S. Adolescents Figure 14. 8 (Based on Centers for Disease Control and Prevention, 2014 i; Kann et al. , 2014. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sexual Orientation • About 5% of U. S. high school students identify as lesbian, gay, or bisexual. • Another 2– 3% are unsure of their sexual orientation. • An unknown number experience same-sex attraction but have not come out to friends or family. • Genetic and prenatal biological influences appear to be largely responsible for homosexuality. • Origins of bisexuality are not yet known. • Stereotypes and misconceptions about homosexuality and bisexuality continue to be widespread. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sequence of Coming Out • Feeling different: – Ages 6– 12 – Sexual questioning by age 10 • Confusion: – Boys: Aware they are gay around ages 10– 15 – Girls: Aware they are lesbian around ages 13– 18 • Self-acceptance: – By end of adolescence – Promoted by parental understanding Copyright © 2016 Laura E. Berk. All Rights Reserved.

Sexually Transmitted Infections (STIs) • Highest rates of STIs are seen in 15 - to 24 -year-olds. • HIV/AIDS is by far the most serious STI. • Human papillomavirus (HPV): – Most common STI – Vaccine available for females ages 11– 26 • Other common STIs: – – Chlamydia Gonorrhea Herpes simplex 2 (genital herpes) Trichomoniasis Copyright © 2016 Laura E. Berk. All Rights Reserved.

Preventing Sexually Transmitted Infections • Know your partner well. • Maintain mutual faithfulness. • Do not use drugs. • Always use a latex condom when having sex with a nonmarital partner. • Do not have sex with a person you know has an STI. • If you get an STI, inform all recent sexual partners. • Get vaccinated to protect against some forms of HPV. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Adolescent Pregnancy • About 625, 000 U. S. adolescent girls became pregnant in most recently reported year: – Almost 11, 000 were younger than 15. – U. S. teen pregnancy rate is higher than in most other industrialized countries. • Number of U. S. teenage births is lower than 50 years ago: – About one-fourth of teen pregnancies end in abortion. – U. S. teenage birth rate is still up to five times higher than in many other developed nations. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Adolescent Pregnancy in Industrialized Nations Figure 14. 9 (Based on World Bank, 2014. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Correlates and Consequences of Adolescent Parenthood • More likely to be poor than agemates who postpone parenthood • Less likely to finish high school, marry, secure employment • Prenatal/birth complications resulting from inadequate diets, smoking, alcohol/drug use, lack of prenatal care • Tendency to pass on personal attributes and to create unfavorable child-rearing conditions Copyright © 2016 Laura E. Berk. All Rights Reserved.

Intergenerational Continuity in Adolescent Parenthood • Mothers’ age at first childbirth predicts age at which their children become parents. • Adolescent parenthood is linked to transfer of unfavorable conditions and characteristics to the next generation: – Home environmental quality and parenting skills – Intelligence and education – Father absence Copyright © 2016 Laura E. Berk. All Rights Reserved.

Preventing Teen Pregnancy Key elements of effective sex education programs: • They teach techniques for handling sexual situations, including refusal skills and communication skills. • They deliver clear, accurate messages appropriate to adolescents’ culture and experiences. • They last long enough to have an impact. • They provide specific information about contraceptives and ready access to them. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Intervening with Adolescent Parents • Young parents need – – – health care. encouragement to stay in school. job training. instruction in parenting and life-management skills. high-quality, affordable child care. • Schools that provide these services – reduce incidence of low-birth-weight babies. – increase educational success. – prevent additional childbearing. • Programs focusing on teenage fathers promote financial and emotional commitment to their children. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Adolescents’ Substance Use and Abuse • Teenage alcohol and drug use: – Pervasive in industrialized nations – Substantial decline since mid-1990 s – Rise in marijuana use since late 2000 s • Varying patterns: – Minimal experimenters are typically psychologically healthy. – A minority of teenagers move from use to abuse. • Correlates and consequences: – Impulsive, disruptive, hostile style is evident in early childhood. – Environmental factors include low SES, family mental health problems. – Serious adjustment problems may include chronic anxiety, depression, antisocial behavior. Copyright © 2016 Laura E. Berk. All Rights Reserved.

Tenth-Grade Substance Use: United States and Europe Figure 14. 10 (Based on ESPAD, 2013; Johnston et al. , 2014. ) Copyright © 2016 Laura E. Berk. All Rights Reserved.

Effective Prevention and Treatment Effective school and community programs • promote effective parenting, including monitoring of activities. • teach skills for resisting peer pressure. • reduce social acceptability of taking drugs by emphasizing health and safety risks. • get students to commit to not using drugs. • provide appealing substitute activities. Copyright © 2016 Laura E. Berk. All Rights Reserved.

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