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Epigenesis- Dynamic system approach, life span development approach, how genes affect behavior, how experience reflects presentation of genes Interactions= bidirectional Chapter Four Early changes in body size  Height  Weight Girls are shorter and lighter in in infancy, have higher fat to muscle tone, Asian American smaller and African Americans larger than normal Trends in development  Cephalcocaudal- head before arms & trunk before legs  Proximodistal – control of head & trunk before arms and legs Changes in body proportions= hands and feet grow faster then body catches up with growth Brain Development  Neurons and Synopses over produced- over abundance  Excess eliminated-Synaptic Pruning OR Programmed cell death -Nature and Nurture Cerebral Cortex  Dived into lobes, 85% of brains weight -frontal lobe= slowest to develop, responsible for cognitive development  Lateralization= specialization of left and right brain hemispheres for different types of brain functions -left hemisphere= sensory info from & control of right side of body, verbal abilities, positive emotion, analytical processing -right hemisphere= sensory info from & control of left side of body, spatial abilities, negative emotions, holistic processing  Corpus collousm unites both hemispheres Brain Plasticity  Plasticity=changes to brain in respoinse to experience -during normal brain development -in response to brain injury -changes with age  At birth hemispheres have already begun to specialize  Highly plastic cerebral cortex has high capacity for learning  If brain damaged, other areas take over tasks  Older kids and adults retain some plasticity Sensitive Periods  Experience expectant growth -Experience “expected” by brain for normal growth….vision easy to test from little vision to increased vision over time  Experience dependent growth - Unique growth from specific learning experiences …. Taught to write, play musical instrument  Orphan studies - Early prolonged insitituzionlization leads to: Decreased brain activity, high stress activity, attention deficits, impulsivity -high quality care can prevent deficits Changing states of arousal  Sleep/ wake pattern moves to night/day… due to melatonin  By 2 years, sleep drops to 12 hr/day  Affected by cultural values -cosleeping ( bed sharing with infants) Influnece on early growth  Heredity -MZ twins more alike in size than DZ  Nutrition -breastfeeding vs. bottle-feeding -risks of overfeeding  Malnutrition -20% of worlds children before age 5 Benefits of Breast feeding  Correct balance of fat and protein -higher in fat and lower in protein  nutrional compleeteness  protects against disease… inhances immune function  healthy physical growth…. Infants breastfed tend to grow faster in height in weight  healthy dental development  ensures digestibility…constipation rate= lower  smooth transition to solid foods… expands flavors infant likes Malnutrition  Marasmus -wasting condition -diet low in all nutrients…occurs in 1 year of life, not receiving enough nutrients in diet, if mother is also malnourished she cant give breast- milk to child -consequences: physical damage, learning deflects, behavioral effects, risk of death  Kwashiorkor -diet very low in protein…calories come from starchy foods, abdomen swells -consequences: physical damage( lose hair, skin rash), learning deficits, behavioral affects -common ages 1-3  Food Insecurity -uncertain access to food -affects 21% of US children -consequences: poor physical growth, learning defeicits Motor Development  Gross= control over actions that help infants get around enviorment  Fine- control over smaller movements (reaching and grasping)  Motor development as dynamic systems - mastery involves acquiring increasingly complex systems of action - motor skills as a system: - CNS development, Bodys movement capacities, childs goals, enviormental support Milestones  Hold head erect when upright - Average 6 weeks - Range 3 weeks-4 months  Lift self by hands -average 2 months range 3 weeks - 4 months  Rolls from side to back -average 2 months -range 3 weeks-5 months  Rolls back to side -average 4.5 months -range 2-7 months  Sits alone -average 7 months  Crawls -average 7 months -range 5-11 months - Standard - Army - Inchworm - Bear - “bum shuffling” - spider - log roll  Pulls to stand -average 8 months -range 5-12 months  Walks alone -average 11 months, 3 weeks -range 9-17 months - Walking -intermediate movements -experimenting with balancing on feet can lead to less stability sitting Reaching and Grasping  Pre-reaching -birth- 7 weeks -poorly coordinated swipes  Reaching -2 hands= 3-4 months -1 hand= 7 months  Ulnar Grasp -Fingers close against palm -Adjust grip to object -4-5 months= move objects from hand to hand  Pincer grasp -use thumb and index finger opposably -9 months  Thelen and collegaues -motor development as dynamic system -lontiudinal research -when infants first reach movment is jerky, but by end of first year movement is smoother and straighter  White and held (1966)- having stimulation leads to early reaching (moderate reached 6 weeks earlier than massive stim) -connection b/w stimulation and onset of reaching -instituinalized infants --control, moderate stim, massive stim -more stim= more crying  Dennis (1960) -Iranian orphans -uninteresting cribs -do not move on own until about 2 years old -at 3-4 years of age were only 15% were walking alone Cultural variations in motor development  Rates and patterns of development affected by; -early movement opportunities, environmental stimulation, child- rearing practices Learning in Infancy