1. Infants, Children, and Adolescents
Chapter 14
Physical Development in Adolescence
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2. Conceptions of Adolescence
Biological Perspective
Puberty
Storm and Stress
Freud – genital stage
Social Perspective
Social and cultural influences
Balanced Point of View
Both biological and social influences
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3. Phases of Adolescence Early 11 or 12 to 14 years
Rapid pubertal changes
Middle
14 to 16 years
Puberty nearly complete
Late
16 to 18 years
Achieves adult appearance and assumes adult roles
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4. Hormonal Changes in Puberty
Growth hormone and thyroxine – increase around ages 8 to 9
Androgens
More in boys
Testosterone
Estrogens
More in girls
Adrenal estrogens
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5. Hormonal Influences on the Body at Puberty
Figure 14.1
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6. Sex Differences in Body Growth in Adolescence
Boys
Girls
Growth Spurt
Starts age 12½
Starts age 10
Proportions
Shoulders broaden
Longer legs
Hips broaden
Muscle–Fat Makeup
Gain more muscle, aerobic efficiency
Gain more fat
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7. Body Growth During Adolescence
Figure 14.2
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8. Motor Development and Physical Activity
Gross-motor development improves with puberty.
Girls: slow and gradual gains
Boys: dramatic spurt in strength, speed, and endurance
Gender gap in skills widens, so gender- segregated physical education begins.
But levels of physical activity often decline.
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9. Decline in Physical Activity
Figure 14.3
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Sexual Maturation
Primary Sexual Characteristics
Maturation of the reproductive organs
Girls: menarche
Boys: spermarche
Secondary Sexual Characteristics
Girls: breasts
Boys: facial hair, voice change
Both: underarm, pubic hair
Other visible parts of the body that signal sexual maturity
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11. Individual Differences in Timing of Puberty
Heredity
Nutrition, exercise
Body fat in girls
Geographical location
SES
Ethnic group
Secular trend
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12. Secular Trends in Menarche
Figure 14.4
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13. Brain Development in Adolescence
White matter increases, gray matter declines.
Pruning continues.
Myelination speeds up.
Improved cognition
Neurons more sensitive to neurotransmitters
Changes in brain’s emotional–social network outpace development of cognitive control network.
Experiences are more intense.
Pleasure- and novelty-seeking; taking drugs increases
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14. Sleep Habits in Adolescence
Sleep needs are still the same as in middle childhood.
9 hours of sleep needed
But adolescents go to bed later.
Biological changes
Social habits
Sleep-deprivation
Achievement, mood problems
More high-risk behaviors
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15. Psychological and Emotional Reactions to Puberty
Reactions to pubertal changes vary.
Culture plays a role.
Preparation
Girls more likely to share with peers
Initiation ceremonies
Adolescent moodiness
Parent–child conflict rises.
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16. Younger and Older Adolescent Emotions Across the Week
Figure 14.5
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17. Consequences of Timing of Puberty
Boys
Girls
Early-Maturing
Popular
Confident, independent
Positive body image
Unpopular
Withdrawn, low confidence, negative body image
More deviant behavior
Late-Maturing
Anxious, talkative, attention-seeking
Negative body image
Sociable, lively
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18. Factors in Reactions to Timing of Puberty
Physical attractiveness – body image
Girls: most want to be thinner, smaller
Boys: most want to be bigger
Strong predictor of self-esteem for both sexes
Fitting in with peers
Prefer peers with similar level of physical maturity
Early maturers in economically disadvantaged neighborhoods face more risks.
Long-term consequences
Early-maturing girls especially at risk
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19. Nutrition in Adolescence
Calorie needs increase.
Poor food choices common
Less fruits, vegetables, milk, breakfast
More soda, fast food
Iron, calcium, vitamin deficiencies common
Many try fad diets or being vegetarians.
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Eating Disorders
Anorexia Nervosa
1% affected
Incidence increasing
Starve out of fear of getting fat
Abnormalities in brain neurotransmitters may make some individuals more susceptible.
Can be fatal
Less than 50% afflicted recover fully
Bulimia Nervosa
2 to 4% affected
Strict diet and exercise, followed by binge and purge
Feelings of guilt and depression typical
Can cause life-threatening damage
Easier to treat
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21. Injuries Increase During Adolescence
Cars
40% of adolescent deaths between ages 15 and 19
High speed
Alcohol
No seat belts
Guns
Sports
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22. Firearm Deaths Among 15- to 19-Year-Olds
Figure 14.6
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23. Sexual Activity in Adolescence
Recent decline in sexual activity
Yet, a high percentage sexually active
Males start earlier than females.
Few partners
American youths begin sexual activity at a younger age.
May often view sexualized media
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The Impact of Culture
Sexual attitudes in the U.S. are relatively restrictive.
Parents give limited information about sex.
Most learn about sex from friends, books, magazines, movies, TV, and the Internet.
The Internet is an especially hazardous educator.
42% of 10- to 17-year-olds viewed pornographic websites on the Internet in the last year.
Of those, 66% said they encountered the images accidentally.
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25. U.S. Adolescents Reporting Sexual Intercourse
Figure 14.7
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26. Characteristics of Sexually Active Adolescents
Personal
Early puberty
Tendency to violate norms
Little religious involvement
Family
Step, single-parent, or large family
Weak parental monitoring, parent–child communication
Peer
Sexually active friends or siblings
Educational
Poor school performance
Low educational goals
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27. Talking About Sex with Adolescents
Reduced sexual risk-taking associated with warm parent communication on sex and contraception
Only about 50% of parents do this because of embarrassment and uncertainty.
Teens are often reluctant to listen.
Mothers tend to have more success.
Suggestions:
Foster open communication.
Use correct terms for body parts.
Use effective communication techniques.
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28. Adolescent Contraceptive Use
Recent increase in contraceptive use
Still, 20% of U.S. teens do not use
Reasons for not using:
Concern about image
Adolescent risk taking
Social environment
Forced intercourse
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29. International Adolescent Contraceptive Use
Figure 14.8
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Sexual Orientation
About 4% of young people identify as lesbian, gay, or bisexual.
An unknown number who experience same-sex attraction have not come out to their family members.
Heredity is an important contributor to homosexuality.
Stereotypes and misconceptions continue to be widespread.
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Sequence of Coming Out
Feeling Different
Ages 6 to 12
Confusion
Ages 11 to 15 boys
Ages 14 to 15 girls
Self-acceptance
Timing varies
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32. Most Common STDs of Adolescence
Disease
Reported U.S. Cases per 100,000
15- to 19-year-olds
Cause
AIDS 20
Virus
Chlamydia
1,956
Bacteria
Cytomegalovirus
unknown
Virus of
herpes family
Gonorrhea
453
Herpes simplex 2
(genital herpes)
1,400
Human
papillomavirus
15,000
Syphilis
4.2
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33. Preventing Sexually Transmitted Diseases
Know your partner well.
Maintain mutual faithfulness.
Do not use drugs.
Always use latex condoms and vaginal contraceptive with nonmarital partners.
Do not have sex with infected persons.
If you get an STD, inform all sexual partners.
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Adolescent Pregnancy
About 740,000 American teen girls each year
15,000 under age 15
One-third end in abortion
86% of teen mothers unmarried
Problems:
Educational achievement
Marital patterns
Economic circumstances
Figure 14.9
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35. Help for Teen Pregnancy
Intervention with Teen Parents
Health care
Help staying in school
Job and life-management training
Parenting instruction
Child care
Adult mentors
Father support
Prevention Strategies
More effective sex education
Skills for handling sexual situations
Clear, accurate messages
Last long enough to have an impact
Info and access to contraceptives
School involvement
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36. Adolescents’ Substance Use
Widespread and rises over adolescence
Varying patterns
Minimal experimenters
Use to abuse
Many factors in abuse
Personal – antisocial
Environmental – family, peers
Different treatments for use and abuse
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37. Tenth-Grade Substance Use
Figure 14.10
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38. Effective Prevention and Treatment
Promote effective parenting, including monitoring of activities.
Teach skills for resisting peer pressure.
Reduce the social acceptability of taking drugs by emphasizing health and safety risks.
Get students to commit to not using drugs.
Provide appealing substitute activities.
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