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

2. 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?

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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”

25. 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

26. 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

27. 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

28. 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

29. 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