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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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”

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

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

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