lecture 1.docx

Why study child development? raising children choosing social policies Child development research can help inform social policies that affect children ex: should kids play violent games? effect is small How much screen time is too much screen time? We don’t know! theres no conclusive data. it...

Why study child development? raising children choosing social policies Child development research can help inform social policies that affect children ex: should kids play violent games? effect is small How much screen time is too much screen time? We don’t know! theres no conclusive data. it matters what they’re doing, now for how long. understanding human nature (nature vs nurture) Child development is vital to understanding how nature and nurture shape human psychology can help explain individual differences between people answers questions like “Are humans innately selfish or not?” What is childhood? Childhood legal def: every human being below age 18 bio def: a human that is physically immature What does it mean to be a child? dependent of adult caregivers Long childhood makes children very vulnerable, thus caring for them is very time-consuming humans have longest childhood compared to other species They’re born useless Animals like giraffes can stand up and walk on their own hours within birth Long childhood in Humans vs. Chimps Human childhood longest amongst primates Why is human childhood so long? Large-brain, narrow hips trade-off an explanation as to why babies are dumber than primates even though it would seem contradicting to evolution Our brains are large for our size, and more complicated/ neuron-dense than any other animal (16.3 bill neurons) larger brain necessitate larger heads narrow hips: ability to stand upright Conflict: how are babies pushed out of utero if the birth canal didn’t get any bigger (like the brain) through evolution? babies evolved to be born earlier, and brain continues to develop once born this allows for more learning long childhood is adaptive for maximizing learning Childhood is fundamentally about learning many aspects of childhood demonstrate that children are adapted to focus on learning highly curious, suggestible, not critical thinkers, imitate others, overestimate own abilities, brains are malleable. focus on learning is only possible if taken care of by adults Child development process of learning of perceptual, cognitive, emotional, and social capabilities that allows an individual to grow from the dependence of infancy to the independence of adulthood independence —> dependence Why focus on Infancy? thats when most changes occur (first 2 years of life) sheds light on nature vs nurture debate uses different methods than for older children What do babies see? before it was believed that babies cant see anything, their vision was non-functional this is false babies can fixate on things and visually scan environment methods in infant research habituation paradigm preferential looking paradigm preferential looking paradigm assess preference fpr diff stimulis shows that infants can differentiate between objects, and shows which one they prefered measured by looking time what is interesting to infants? familiar stimuli we can do lab induced familiarization which is when we familiarize infant to a new object in the lab using a few trials (make sure they don’t get bored, as this can change results) more complex stimuli i.e. more saturated, more shapes, more personality. habituation paradigm we habituate or expose infants to an object for a long time (till they get bored of it) then we can show 2 objects, they will look at the new object. this shows that they can differentiate between them and that infants prefer the new object measured by looking time if they look at the 2 things equally, they cant tell the difference familiarity vs novelty in general kids prefer familiar stimuli but prolonged exposure to a stimulus will shift interest to new stimulus. visual acuity sharpness of visual discrimination infants have poor visual acuity they prefer to look at things w high visual contrast n more complex shapes aren’t able to discriminate between objects w lower contrast due to immaturity of cones adult like visual acuity at 8 months color perception at birth: black n white 2 months: color appears, red is first 5 months: adult-like color perception. can differentiate between hues and color categories visual scanning at birth: you can visually scan the environment but only stationary objects 4 months: you can scan slowly moving objects (Follow) 8 months: adult like visual scanning face perception infants prefer faces or face-like stimuli why are infants drawn to faces? top-heavy stimuli is preferred (face is top heavy) preferential looking paradigm to test this: face upside down face top heavy scrambled face bottom heavy scrambled face showed a preference for face n top heavy face therefore, general bias for top heavy therefore, not a special bias towards FACES only but general bias for top heavy stimuli seeing moms face infants prefer their moms faces (they quickly learn to recognize it) becoming a face specialist face specialist: better at distinguishing faces that are frequently seen occurs at 1st year of life evidence: 6 month old children can differentiate between different monkey faces diferent human faces 9 month old children can only accurately differentiate between human faces therefore, they have now become face specialists. they can differentiate between faces frequently seen. they have gone from being face generalist i.e. can differentiate between all faces in general. perceptual narrowing tuning of perceptions to specific sensory input that we frequently encounter this causes us to become face specialists. evidence is other-race-effect decline in ability to distinguish between stimulus not frequently encountered like monkey faces result from synaptic pruning synaptic pruning elimination of synapses to increase efficiency of neural communication use it or lose it synaptogensis formations of synapses between neurons occurs rapidly right after birth other-race-effect people find it easier to distinguish between faces of ur own race, rather than faces of another race. evidence caucasian infants habituated to faces from their own race, or another race then present habituated face + another face of that race will they know how to differentiate properly since they were habituated? 6 months: differentiate all races 9 months: no. they can only differentiate their own race not innate, but experience. if equally exposes to all races, then no other-race-effect face perception in children w ASD have difficulty with face perception because they dont like to look at faces, they prefer geometric shapes more perceptual constancy perception of object is the same regardless of physical differences in the retinal image of the object (color, shape, size, etc.) failure of color constancy is the gold n white or blue n black dress evidence: is perceptual constancy present from birth? habituation paradigm with newborns to a cube present the cube + a bigger sized cube presented in a way where it looks equal in size to the habituated cube infants look more at the new bigger cube because they can tell that its bigger i.e. perception of cube is different than the retinal image because retinal image shows it to be smaller than it acc is but when we perceive it it looks bigger bc the size should be constant suggests that perceptual constancy is innate object segregation ability to identify objects that are separate from each other clues: diff colors, away from each other, movement patterns i.e. if they move separately evidence: is object segregation innate? showed infants video of rod moving behind a box. habituated to it then showed two rods: 1 complete long rod, another video is 2 broken rods moving separately. 6 month old children: looking at the broken rods more, suggesting that they perceived a full rid behind the box. showed that they understand that the rod was a single object newborns: looked at both vids the same indicates that they didnt understand that the rod behind the object was a single object object segregation is not innate, it has t depth perception binocular disparity difference of image location in the retinal image of each eye. info is combined using visual cortex. binocular disparity extracts the depth info 4 months old sensitive period for binocular disparity birth-3 years result of brain maturation as long as infants receive normal info input if no normal info until age 3, they may fail to develop normal binocular vision and have life long difficulty with depth perception monocular disparity depth cues perceived from one eye 6-7 month old assess visual cliff 6 months old will not crawl over visual cliff but younger kids will suggests that monocular disparity is developed through experience innate perceptual constancy and top-heavy stimuli preference experience depth perception, object segregation, face perception brain maturation visual acuity, color perception, visual scanning At birth rudimentary visual scanning, poor acuity, preference for high contrast, gray scale, preference for faces vs. non-faces, perceptual constancy 2 months colour vision appears 4 months object segregation and binocular depth perception appear 5 months adult-like colour perception 6 months face generalists, monocular depth perception appears 8 months adult-like visual scanning and visual acuity 9 months face specialists through perceptual narrowing

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