Physical Development in Adolescence Children 15 Physical Development in Adolescence John W. Santrock

Socioemotional Development in Adolescence What Is the Nature of Adolescence? What Are the Physical and Psychological Aspects of Puberty? What Are the Dimensions of Adolescent Sexuality? How Can Adolescent Problems and Health Be Characterized?

What Is the Nature of Adolescence? Views of Adolescence Biological view: Hall’s view that adolescence is a turbulent time of “storm and stress” Adolescence, like childhood, is an interaction of genetic, biological, environmental, and social factors

What Is the Nature of Adolescence? Today’s adolescents exposed to complex menu of lifestyle options Most have positive self-images, finish high school, and have self-control U.S. adolescent drug use highest of all Western industrialized countries

Determinants of Puberty What Are the Physical and Psychological Aspects of Puberty? Determinants of Puberty Puberty: period of rapid physical maturation Heredity: programmed genes Hormones: testosterone, pituitary gland, gonads, androgens, hypothalamus, and estradiol Weight and body fat

What Are the Physical and Psychological Aspects of Puberty? Gonadarche: sexual maturation and the development of reproductive maturity Menarche: girl’s first menstrual period Spermarche: boy’s first ejaculation of semen

Growth Spurt Most rapid increases in growth since infancy What Are the Physical and Psychological Aspects of Puberty? Growth Spurt Most rapid increases in growth since infancy Adolescents gain weight approximately the same rate as they gain height Changes in hip and shoulder width

Sexual Maturation Male Female Breasts enlarge or pubic hair appears What Are the Physical and Psychological Aspects of Puberty? Sexual Maturation Male Increase penis and testicle size Pubic hair growth First ejaculation Maximum growth Hair in armpits Voice change Facial hair Female Breasts enlarge or pubic hair appears Hair in armpits Growth Hips widen First menstruation

Secular Trends in Puberty What Are the Physical and Psychological Aspects of Puberty? Secular Trends in Puberty Patterns over time, especially across generations U.S.: average age of menarche declined about two to four months per decade much of 20th century Improved health and nutrition

Normal Range and Average Development of Sexual Characteristics in Males and Females Completion (avg) Females Onset (avg) Males Age in years 15 8 9 18 14 16 11 13 10 12 17 Height spurt Menarche Penile growth Breast growth Testicular growth Growth of pubic hair Fig. 15.3

Median Ages at Menarche in Selected Northern European Countries and the United States from 1845 to 1969 Finland Sweden U.S.A. Norway U.K. 1840 1860 1880 1900 1920 1940 1960 18 17 16 12 15 14 13 Year Median age (years) at menarche 1980 Fig. 15.4

Psychological Dimensions of Puberty What Are the Physical and Psychological Aspects of Puberty? Psychological Dimensions of Puberty Body image Preoccupation, dissatisfaction with changing body Girls more negative than boys Early and late maturation

Early and Late Maturation What Are the Physical and Psychological Aspects of Puberty? Early and Late Maturation Girls Boys Early Risk of school, substance, eating, sex problems More independent Positive self- perception Successful peer relations Late Early body dissatisfaction, happier later Stronger sense of identity in 30s

Early- and Late-Maturing Adolescent Girls’ Perceptions of Body Image in Early and Late Adolescence Late development Early development Mean -.20 +.30 -.30 -.10 +.10 +.20 Body Image Score Grade 10 Grade 6 Fig. 15.5

What Are the Physical and Psychological Aspects of Puberty? The Brain Activity during emotional processing differs in adolescents and adults Prefrontal lobe not fully developed, “gut” reactions from adolescents Influences of reward and punishment; adolescent difficulty in controlling behavior More research needed

Developing a Sexual Identity What Are the Dimensions of Adolescent Sexuality? Developing a Sexual Identity Time of Ambivalence: sex used in movies/videos/TV shows/music, advertisements, and Internet Frequent viewing tied to casual sex attitudes Mastering sexual feelings and forming sense of sexual identity is lengthy, multifaceted

Sexual Activity Typical progression of sexual behavior What Are the Dimensions of Adolescent Sexuality? Sexual Activity Typical progression of sexual behavior Necking, kissing Petting Oral sex or intercourse 50% have had intercourse by age 17, 80% by age 19

What Are the Dimensions of Adolescent Sexuality? Sexual Activity Adolescent males more likely to report being sexually active than females Culturally: Asian Americans have more restrictive timetable for sexual activity African-American males and inner-city adolescents more sexually active; risk factors exist and sexual problems

Sexual Intercourse Rates in U.S. Adolescents What Are the Dimensions of Adolescent Sexuality? Sexual Intercourse Rates in U.S. Adolescents 19 100 80 60 Percentage 20 15 16 17 18 40 Fig. 15.7

Homosexuality in Adolescence What Are the Dimensions of Adolescent Sexuality? Homosexuality in Adolescence Diverse patterns of attractions Homosexual identity, attractions, behaviors increase with age 6% of 18-year-olds “predominantly homosexual” Some stop homosexual behavior after adolescence

Contraceptive Use in Adolescence What Are the Dimensions of Adolescent Sexuality? Contraceptive Use in Adolescence Contraceptive use increasing Nearly 80% use at first intercourse Pill most popular Also injectables, withdrawal, implants Younger adolescents less likely to use Higher risk of pregnancy and disease

Sexually Transmitted Infections What Are the Dimensions of Adolescent Sexuality? Sexually Transmitted Infections HIV and AIDS caused greatest impact in world Other STDs: chlamydia, gonorrhea, syphilis, genital herpes At greatest risk: drug users, poor, young homosexuals, Latinos and African Americans

Risks of Adolescent Pregnancy How Can Adolescent Problems and Health Be Characterized? Risks of Adolescent Pregnancy Risk factors Health problems for baby and mother Low education for mothers Low income Educational, behavioral problems for children

How Can Adolescent Problems and Health Be Characterized? Substance Use Cigarette smoke begins primarily in childhood and adolescence Alcoholics begin drinking habits in high school and college Most adolescents use drugs at some point Drug use poses hazard to development when adolescents use for “coping”

Alcohol Use and Cigarette Smoking How Can Adolescent Problems and Health Be Characterized? Alcohol Use and Cigarette Smoking Alcohol use dropping, rates still high 19% of eighth-graders, 48% of seniors More boys than girls Smoking Decreasing use among adolescents Social disapproval a reason to quit Earlier the onset, the more damaging

Eating Disorders Impact of body image and parenting How Can Adolescent Problems and Health Be Characterized? Eating Disorders Impact of body image and parenting Obesity and successful interventions Anorexia nervosa: relentless pursuit of thinness through starvation Bulimia nervosa: consistently follows a binge-and-purge eating pattern

How Can Adolescent Problems and Health Be Characterized? Adolescent Health Establishing bad habits sets risks for adult health problems Premature disability and mortality U.S. adolescents exercise less New interest in adolescent sleep patterns; biological clocks changing

How Can Adolescent Problems and Health Be Characterized? Adolescent Health Adolescents have more acute health conditions than adults; underutilize health system, especially males Barriers for adolescents Costs Poor organization Availability of health services Confidentiality of care

The Leading Causes of Death in Adolescence in Canada How Can Adolescent Problems and Health Be Characterized? The Leading Causes of Death in Adolescence in Canada Accidents Suicide Alcohol and Illicit Drug use