Infant eye tracking is jerky (saccade), and while that’s good because it lets them get lots ofvisual information, it’s also a very disorganized way to view the world. Their motor developmentaffects their perception and vice-versa, so when they try to grab things they often overshoot andmiss.Infants are born legally blind with “visual acuity” (how well they see) of only 20/400.Children cannot see in 3D until 6 months of age, until they start crawling.Their 3D perception of the world is because of 4 things:1. Retinal disparity: what each eye sees is a little different, and the amount of disparitybetween two images is used as a cue for distance. Some kids have difficulty with this,which is a condition we call strabismus / lazy eye.2. Occlusion: A fancy term for when things are blocked from view3. Texture gradient: Babies often confuse texture with what an object actually is. Forexample, children don’t like walking on glass or transparent objects because they thinkthey’re going to fall right through. He demonstrated this with the visual cliff, a type ofcrib that was made partially of glass and looked like a “cliff.” The babies avoided this cliffbut walked on the rest of the crib no problema. They can use cues from texture gradient to tell when something is close or faraway4. Relative size.Auditory threshold (minimum amount of sound someone can register) is higher for newbornsand infants than adults. Meaning that their hearing isn’t as well. However, whatever pitch theyhear better is based on the pitch of their motherThe auditory brainstem response refers to the neurons of the brain stem that fire when theypick up a soundHabituation is a measure of how quickly babies get bored by the same stimulus over and overagain. Often used as an IQ test for babiesSensory integration is when we combine multiple pieces of sensory information, mainly sight +sound. Intersensory redundancy is good, because it shows that we are registering andcombining the same information over and over again. If something visual is moving with sound,it literally helps you hear betterSmell and taste are quite sensitive from a young age. “Sweet tooth” often develops becausesugars are so high-calorie, so infants naturally like them more. Touch is even more sensitivethan most adults, with infants feeling higher pain from shots● Touch-wise, topical anesthesia works: if we rub the area, it won’t hurt as much when wegive it a shot.● Babies aren’t good multi-taskers, so if we give children sweets it takes their attention offthe painBabies’ perception functions as a result of how they interact with the world------Our sense of balance comes from vestibular systemWe know where limbs are, which is a sixth sense called proprioception/kinesthetic senseDynamic systems theory says that the connection between action and perception is all aboutdeveloping skills and then using them togetherGross motor development = moving the whole bodyFine motor development = moving individual digits, very random at first but gets betterOrienting system = notices changes in the environmentFocus system = blocks out environmental stimulusQuick Review:● Vision is by far the worst of the senses after birth● Infant hear well but not as good as adults● Auditory threshold higher in newborns, lower in children (best for human voice pitches)● Infant hearing is like you with a bad cold● Smell is better than adults● Can taste apparently everything, more sensitive than adults● Same nerves as adults, but it hurts more anyways● Differentiation of component skills and then integrating