1. Physical Development in Infancy
Children 6
Physical Development in Infancy
John W. Santrock

2. How Do Infants Grow and Develop Physically?
Images of Children
Bottle-feeding newborns in impoverished countries has become a trend
Formula mixed with unclean water
Bottles often unsterilized
Many children get common illnesses; may die
Breast milk would immunize newborn
Hospitals have vital role in educating mothers

3. Cephalocaudal and Proximodistal Patterns
How Do Infants Grow and Develop Physically?
Cephalocaudal and Proximodistal Patterns
Cephalocaudal: size, weight, and feature differentiation gradually work from top to bottom
Proximodistal: growth starts at center of body and moves toward extremities

4. How Do Infants Grow and Develop Physically?
Height and Weight
Average North American newborn is 20 inches and 7½ pounds
Birthweight doubled by age 4 months; tripled at end of first year
Growth during first year averages 1 inch per month
1½ times birth length at end of 1st year

5. Height and Weight Average 2-year-old
How Do Infants Grow and Develop Physically?
Height and Weight
Average 2-year-old
26 to 32 pounds and 32 to 35 inches tall (almost half of their adult height)
Growth rate considerably slower in second year

6. Brain Development Myelin sheath: layer of fat cells
How Do Infants Grow and Develop Physically?
Brain Development
Myelin sheath: layer of fat cells
Encases most axons
Insulates nerve cells
Synapses: tiny gaps
EEG activity spurts about 1½ to 2 years of age

7. Early Experience and the Brain
How Do Infants Grow and Develop Physically?
Early Experience and the Brain
Environmental experiences important in brain’s development; enriched environments enhance growth
Infant’s brain waiting for experiences to determine connections among neurons

8. Sudden Infant Death Syndrome (SIDS)
How Do Infants Grow and Develop Physically?
Sudden Infant Death Syndrome (SIDS)
Infant stops breathing, usually during night, and dies without apparent cause
Also known as “crib death”
Prone sleeping reduces risk by 5 to 10 times

9. Sudden Infant Death Syndrome (SIDS)
How Do Infants Grow and Develop Physically?
Sudden Infant Death Syndrome (SIDS)
Increased risks if:
Lower birthweight
Siblings with SIDS
Sleep apnea
Lower SES groups
Exposure to cigarette smoke
Placement in soft bedding

10. Nutrition Healthy infants need Loving, supportive feeding environment
How Do Infants Grow and Develop Physically?
Nutrition
Healthy infants need
Loving, supportive feeding environment
50 calories per day per pound of weight
Fat; very important for growth
Breast milk (nature’s food)
Demand feeding becoming more popular

11. Breast-Feeding Versus Bottle-Feeding
How Do Infants Grow and Develop Physically?
Breast-Feeding Versus Bottle-Feeding
Breast-feeding recommended
Appropriate weight gain, lowers obesity risk
Prevents or reduces allergies and infections
Promotes neurological and cognitive growth
Lowers risk of SIDS and cancers
Better visual acuity and bone density
The only option in poor countries

12. Health Immunization begins in infancy Accident Prevention
How Do Infants Grow and Develop Physically?
Health
Immunization begins in infancy
Accident Prevention
Increased monitoring needed in infancy
Asphyxiation: leading cause of death under 1
Chocking hazards: toys, food
Burn risks: sun, electrical, heaters, hot water
Other risks: car accidents, cuts, pet bites

13. How Do Infants Develop Motor Skills?
Reflexes
Rooting: reaction when infant’s cheek is stroked or side of the mouth is touched
Sucking: automatic sucking when something is placed in newborn’s mouth
Moro reflex: startle response causes rapid closing of arms and legs
Grasping: when something touches palm

14. Gross Motor Skills Large muscle activities Development of posture
How Do Infants Develop Motor Skills?
Gross Motor Skills
Large muscle activities
Development of posture
Learning to walk; locomotion, balance, and practice
Development in second year
Pull toys, climb stairs
Walk quickly, run stiffly

15. Cultural Variations in Guiding Infants’ Motor Development
How Do Infants Develop Motor Skills?
Cultural Variations in Guiding Infants’ Motor Development
Infants reach motor milestones in different cultures based on activity opportunities
Variations not large
Milestones reached within normal age ranges

16. Fine Motor Skills Reaching and grasping
How Do Infants Develop Motor Skills?
Fine Motor Skills
Reaching and grasping
Perceptual-motor coupling necessary
Initially move shoulders and elbows crudely; later move wrists and rotate hands
Coordinate thumb and forefinger
Experience affects reaching and grasping; becomes more refined during first 2 years

17. Studying Infant Perception
How Can Infants’ Sensory and Perceptual Development Be Characterized?
Studying Infant Perception
Infant cannot talk
Head movement indicates some vision
Visual preference method: Fantz measured length of gaze and patterns of preference in “looking chamber”

18. Studying Infant Perception
How Can Infants’ Sensory and Perceptual Development Be Characterized?
Studying Infant Perception
Habituation and Dishabituation
Habituation: decreased responsiveness to a stimulus after repeated presentations
Dishabituation: recovery of a habituated response after change in stimulation
Tracking: applied to vision and hearing
Equipment: high-amplitude sucking

19. Visual Perception Visual acuity and color Perceiving patterns
How Can Infants’ Sensory and Perceptual Development Be Characterized?
Visual Perception
Visual acuity and color
Perceiving patterns
Perceptual constancy—size, shape
Depth perception
Visual expectations

20. Other Senses Hearing: begins in womb Touch and Pain
How Can Infants’ Sensory and Perceptual Development Be Characterized?
Other Senses
Hearing: begins in womb
Touch and Pain
Smell: present shortly after birth
Taste: may exist before birth