Transcript PSYC 2020 Santrock_Ch15

Slide 1
15
Physical Development in
Adolescence
John W. Santrock
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 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?
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Nature of Adolescence?
Slide 3
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Nature of Adolescence?
Slide 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 selfcontrol
• U.S. adolescent drug use highest of
all Western industrialized countries
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 5
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 6
Puberty
• Gonadarche: sexual maturation and the
development of reproductive maturity
– Menarche: girl’s first menstrual period
– Spermarche: boy’s first ejaculation of
semen
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 7
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 8
Sexual Maturation
Male
Female
– Increase penis and
testicle size
– Pubic hair growth
– First ejaculation
– Maximum growth
– Hair in armpits
– Voice change
– Facial hair
– Breasts enlarge or
pubic hair appears
– Hair in armpits
– Growth
– Hips widen
– First menstruation
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 9
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
Normal Range and Average
Males
Development of Sexual Characteristics
Females
in Males and Females
Onset (avg)
Completion (avg)
Slide 10
Height
spurt
Penile growth
Menarche
Testicular growth
Breast growth
Growth of
pubic hair
8
9
10 11 12 13 14 15 16 17 18
Age in years
Fig. 15.3
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
Median Ages at Menarche in Selected Northern European Slide 11
Countries and the United States from 1845 to 1969
Median age (years) at menarche
18
17
16
Norway
Finland
Sweden
U.K.
U.S.A.
15
14
13
12
1840 1860 1880 1900 1920 1940 1960 1980
Year
Fig. 15.4
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 12
Psychological Dimensions
of Puberty
• Body image
– Preoccupation, dissatisfaction
with changing body
– Girls more negative than boys
• Early and late maturation
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 13
Early and Late Maturation
Girls
• Risk of school,
substance, eating,
Early sex problems
• More independent
Late
• Early body
dissatisfaction,
happier later
Boys
• Positive selfperception
• Successful peer
relations
• Stronger sense
of identity in 30s
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
Early- and Late-Maturing Adolescent Girls’ Perceptions
of Body Image in Early and Late Adolescence
Slide 14
Early development
Late development
Body Image Score
+.30
+.20
+.10
Mean
-.10
-.20
-.30
Grade 6
Grade 10
Fig. 15.5
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Physical and Psychological Aspects of Puberty?
Slide 15
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 16
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 17
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 18
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 19
Sexual Intercourse Rates
in U.S. Adolescents
100
80
60
40
20
Fig. 15.7
0
15
16
17
18
19
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 20
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 21
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Dimensions of Adolescent Sexuality?
Slide 22
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 23
Risks of Adolescent
Pregnancy
• Risk factors
– Health problems for baby and mother
– Low education for mothers
– Low income
– Educational, behavioral problems for
children
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 24
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”
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 25
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 26
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 27
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
Slide 28
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
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.
How Can Adolescent Problems and Health Be Characterized?
The Leading Causes of
Death in Adolescence in
Canada
Slide 29
• Accidents
• Suicide
• Alcohol and Illicit Drug use
© 2007 The McGraw-Hill Companies, Inc. All rights reserved.