1. Chapter 5
The Physical Self

2. Plasticity: Responsive change to stimulation
Lack of normal experiences
Abnormal brain development
Hubel & Weisel’s kittens
Stimulating experiences key
Plasticity greatest at critical period
Late prenatal, early infancy
Brain always responsive to stimulation

3. Later Brain Development
Brain grows post-birth
Birth: 25% of adult weight
Age 2: 75% of adult weight
Age 5: 95% adult weight (full weight by 16)
Mylenation through adolescence
Dendritic growth (more synapses)
Lateralization: 2 hemispheres (interdependent)
Left: language, complex thought
Right: spatial skills, visual motor, emotions
Corpus callosum

4. The Aging Brain Normal aging Brain weight decreases
Gradual, mild degeneration
Not senility
Brain weight decreases
Plasticity throughout lifespan
Individual variation

5. The Infant: Reflexes Survival: aid in survival Primitive: no clear use
Eye-blink
Rooting
Primitive: no clear use
Babinski
Stepping
Forerunners of useful voluntary behavior
Unrelated to later expression of behavior
Fade in early months

6. The Infant: Behavioral States
Health = organized/unique pattern
Sleep-wake pattern key
By 6 mo: Sleep-wake patterns established
Birth-6 months 50% sleep is REM
Regulate sensory stimulation
Growth (brain)
Ability to learn
Operant conditioning
Sucking increases to sweet taste

7. Growth in Infancy Fits and starts (no steady) Principles of Growth
First few months 1 ounce/day, I inch/month
By age 2: About 1/4 adult height
Inadequate nutrition = growth retardation
Catch-up growth
Principles of Growth
Cephalocaudal: Head to feet
Proximodistal: Center out
Orthogenic: Undifferentiated to differentiated

8. Motor Skills in Infancy
Rhythmic stereotypies key
Repetitive movements before, not after skill develops
Dynamic systems approach
Skills develop over time via self-organization process
Sensory feedback to movements critical
Nature (maturation) & Nurture (experience)
Connected to perceptual-cognitive development

9. Growth in Childhood Slows down, but is steady
2-3 inches height & 5-6 lbs/year
Large and small muscle control improves
Better coordination, movement
Reaction time decreases
Adaptation to a changing environment
Hand-eye movements improve

10. Adolescence Physical growth spurt
Triggered by hormones
Gender differences
Earlier for girls
Boys: more lean muscle, girls more fat
Puberty (primary & secondary sexual characteristics)
Menarche (average 12.5 year)
Semenarche (average 13)

11. Figure 5.7a

12. Figure 5.7b

13. Variations in Timing (early & late development)
Causes
Genetic differences
Environmental influences
Secular trend
Nutritional status
Family stress
Psychological implications
Early easier for boys than girls
Late easier for girls than boys

14. Psychological implications
Girls have poorer body images
Body fat, cultural myths contribute to negative body image for many young women
Boys have more positive views of their changing bodies
62% view semenarche positively v. 23% girls & menarche
Puberty often leads to increased independence, conflict
Early v. late development (differences fade over time)
Early easier for boys than girls
Girls can develop problematic behavior from older peers
Late easier for girls than boys
Boys tend to be more anxious, less confident/athletic

15. Adolescent Physical Behavior
Noticeable increases in strength
Continues for boys
Levels off for girls
Biological differences: Advantages for boys
Gender-role socialization
If athletic, advantages for girls

16. Adulthood Aging steady but not apparent before 40s
Hair & skin changes, weight gain
Weight and muscle loss in the 60’s
Sedentary lifestyle
Low education levels
Osteoporosis: Calcium, exercise
Osteoarthritis

17. Physiological systems decline from 20s
Adulthood: Functioning & health
Physiological systems decline from 20s
Wide individual differences
Exercise combats decline
Reserve capacity
Changes not universal
Vast majority of older adults retain adequate function
70 or older: 88% men 82% women can walk 1/4 mile
92% men 88% women can climb 10 stairs w/o rest

18. Male Climacteric gradual
Adulthood: Functioning & health
Menopause
Gradual process taking 5-10 years
Periods more/less frequent & less regular
Estrogen levels decline
Lack of ovulation and conception impossible
Hot flashes key symptom (Psychological disturbance not common)
HRT: many risks & benefits
Male Climacteric gradual
Levels of testosterone declines
May never be completely infertile

19. Aging:Psychological implications
Ageism internalized
Majority function independently
Majority have high sense of well-being, contentment

20. Physical Behavior in Older Adults
Slowing down
Balance and strength decline
Exercise beneficial
Disease, disuse, and abuse
Birren study of men age 65-91
Increased vulnerability to disease
Use it or lose it
Abuse in lifestyle