Infant Development PDF

Module 2 Readings Chapter 4 & 5 CHAPTER 4 Eye Head Control (Summary): -traditionally, looking was considered passive; we now know it is active, like reaching -eye tracking shows that looking is a motor action rather than a perceptual system -looking is a performatory action system that infants use t...

Module 2 Readings Chapter 4 & 5 CHAPTER 4 Eye Head Control (Summary): -traditionally, looking was considered passive; we now know it is active, like reaching -eye tracking shows that looking is a motor action rather than a perceptual system -looking is a performatory action system that infants use to respond to and initiate changes in their environment -looking helps infants gain a sense of agency, a distinct self that can affect the environment around them -still-face experiments: infants become distressed when a mother responds to their looking and facial interactions with a still face -at first, looking is opportunistic for infants because they lack the strength to lift their heads or coordination to turn their heads with their eyes -2-3 weeks after birth: infants can lift their chins from the floor when prone -5-10 weeks: infants can lift their heads and chests from the floor -3 months: infants can lift their heads steady while propping themselves up on the floor in a prone position, and/or when held upright on their parents’ laps -1 month: infants begin to engage in smooth pursuit with a large, slow object on a predictable path for short periods of time (with caregivers help to hold their head) -smooth pursuit improves quickly over time -4-5 months: infants can coordinate their head and eye movements to follow objects smoothly, rather than the eyes having to stay ahead of the object to keep up due to poor head coordination -6 months: infants are better at making anticipatory eye movements while tracking an object behind a shield than at 4 months (object knowledge) -better prospective control -looking = learning Manual Skills (Summary): -many fetus and infant “movements” are really spontaneous, aimless movements (kicking in the womb, reaching) with no intent to exert change on the environment -6 weeks gestation: spontaneous motor movement begins -manual exploration begins in the womb (touching umbilical cord, uterine wall, fetus’s own face) -prenatal-1 year: spontaneous arm movements persist in high frequency (arm flailing, waving fingers, rotating arms) -spontaneous manual activity can become goal-oriented; infants shown a slideshow moved from neutral facial expressions during arm flailing to joyful expressions during flailing -reaching is intertwined with the development of postural control -4 months: first goal-directed reaching appears when lying on back -5 months: goal-directed reaching while lying on stomachs propped on one arm -6-8 months: goal-directed reaching while sitting with legs outstretched in a V -better sitting abilities = more sophisticated reaching and grabbing behaviours -12-18 weeks: infants reach towards objects WITH FULL POSTURAL SUPPORT from outside -first supported reaches end with object contact, not object grasping -31 weeks: infant’s reaching and grabbing becomes as smooth and straight as an adult -1 year: prospective control of reaching is developed to catch objects moving at diff speeds and from behind an occluder -5 months: infants change their grip to match the size of the object -7.5 months: infants change orientation of hand to match orientation of target -9 months: infants open their hand to match the object’s size and start grasping in anticipation of holding the object -10 months: infants can pincer-grip small objects -6-10 months: infants are discovering varying surfaces of objects and the relations between them (squishy, hard, smooth, etc). -exploration is intrinsically motivating for infants -manipulating objects, exploring surfaces, and relate objects to surfaces = improvements in cognitive function -ex. Means-end reasoning in tools use, like using sticks to draw items closer -9 months: can grab a spoon but not use it efficiently -18 months: grab the correct end of spoon and grasp appropriately -24 months: infants can modify their grip to eat from a bent spoon handle Locomotion (Summary): -locomotor development is NOT a series of orderly stages -babies typically crawl within 6 months, but some skip the crawling stage -experience better predicts locomotive progress than age or body dimension; practice is best -7-13 months: infants pull themselves up and move side to side holding onto something -~1 year: infants begin taking independent walking steps -~11-15 months: normal age range for walking onset -locomotive experience is not a forced march or rote repetition; under the best conditions, infants start and stop at will and crawling and walking steps are highly variable -home diaries, step-counters, video-tracking shows staggering quantity and variety in locomotion -”the self in motion”: when infants move or sit, their bodies sway around their base of support -> which generates info specifying the speed and direction of movement -> allows infants to produce a compensatory postural sway in the opposite direction -more experience with balance and locomotion = increased behavioural flexibility -the “visual cliff” experiment -methodological problems: limited testing after infants realize the fake danger, size of the drop-off is fixed -in less familiar postures, infants showed poor adaptive decisions with th cliffs -similar findings with the slopes experiment -experience promoted flexibility for practiced action systems (ex. crawling) but not for newly acquired ones (ex. A new walker) -infants almost never automatically or immediately learned from falling; one-trial learning increased with age -locomotion = new means-end probem solving -infants who walked took the presence or absence of a handrail as well as the width of a bridge into consideration when attempting to cross it (or not cross it) CHAPTER 5 -early theories emphasized an empiricist view of perception = infants perceive very poorly and experience is vital for the development of the senses -Piaget and Darwin -research in the last 50 years has show the nativist view should be combined with the empiricist view: while experience is important, perceptual development is present at a surprisingly early age Touch Touch Sensitivity -touch is the first sense to develop in the womb -even newborns can discriminate between nipple texture and detect weight change in objects Temperature -from mouthing or handling objects (cold/warm nipples and water) newborns can differentiate between cold and warm temperatures Pain -26 weeks from conception: neural pathways for pain are present -pain can be measured in infants from facial expressions, heart rate, and crying -pain can be relieved by soothing stimuli same as in adults -pain develops more strongly as the infant ages Taste -fetuses can discriminate between sweet and noxious -amniotic fluid contains different tastes and provides the fetus with this sense experience as a result -the newborn can discriminate between sweet, sour, salty, and bitter -this is evident in their facial expressions -at birth, the infant has food preferences -birth-3 months: infants become more active and accepting of new tastes -in the first year, the infant will suck any suckable object including food -hatred of foods doesn’t develop until after 2 years -early infancy = intrinsically hunger-driven, later infancy = replaced by extrinsic factors (meal times and appropriate foods for certain times of the day) Smell -9-10 weeks after conception: the fetus breathes in and exhales amniotic fluid -gives the fetus experience with odours; at birth the sense of smell is fully developed -newborns show by their faces that they have clear odour preferences and aversions -shown through habituation procedures that infants can discriminate between subtle smells Hearing - Sound, Voices, and Speech Basic Auditory Abilities - Hearing and Localizing Sounds -infants can hear low frequencies similar to the ability of adults -newborns can localize sounds, and will turn their head in the direction of a sound even in a room of complete darkness Auditory Preferences at Birth -newborn babies have preferences for their mothers’ voice over a strange woman’s voice -this preference begins in the womb -newborn babies showed a preference for stories read to them when they were in the womb -infants prefer baby-directed speech or motherese (baby talk) Perception of Speech -newborn babies responded more to happy speech patterns than sad or angry -newborn babies preferred speech patterns in their native languages that they wouldve been exposed to in the womb -speech and language perception begin in the womb -infants are born with the ability to discriminate between sounds in all of the world’s languages -this ability diminishes around the 1-year mark and babies become “native listeners”! Visual Perception Basic Visual Abilities -vision is the least developed of the senses at birth -visual acuity of a newborn is 10-30 times worse than that of an adult -infants see well at near distance, which contains things of most interest to their developing worlds -visual acuity improves immensely at about 6 months -sensitivity to variations in contrast, colour vision, visual accommodation, precise control over eye movements, depth perception, binocular vision = all relatively weak at birth but develop rapidly within 6 months or so An Organized Visual World -size constancy is an organizing feature of perception that is present at birth -newborn infants can imitate facial expressions soon after birth -Piaget previously thought imitation did not appear until 2 years old! -a baby must be able to match what it sees to some inborn knowledge of its own face -functional mirror neural system at birth??? -3 months: infants can match a familiar voice with its face, knows that male/female faces are in diff categories, can discriminate between faces of their own and other races -1 year: perceptual narrowing effect is present, similar to that of the speech one; infants can discriminate between human but NOT monkey faces The Infant’s World of Objects -~2 months: babies realize that partly occluded objects are whole -~5-6 months: infants realize that 2 objects touching are 2 separate objects and not 1 object -6-8 months: infants have learned about structural support and gravity (though not a COMPLETE understanding) Posture and Balance -development of vestibular system (sense of bodily posture and balance) and kinesthetic feedback (nerves in our bodies telling us where our body parts are) begins in the womb Infant Reaching -Reaching: infants acquire stable control over their heads -> reorganization of muscle patterns so the infants can stabilize their heads and shoulders -> successful reaching follows from this base -4-5 months: visually directed reaching appears after this base is developed The Moving Room -infants will often make inappropriate postural controls like adults do! -15-34 months: of the infants tested, they fell forward when the fake walls outside moved forwards, and backwards when they moved backwards Coordination Between the Senses -intersensory redundancy: information that tells us that info from stimulus 1 should be linked with info from stimulus 2 -this is important for infants learning word-object association or many other things! -evidence suggests that infants actually can discriminate between the different sensory information they receive; it is not always just a big jumble. However, a lot of information that is seemingly unrelated at once can be confusing for an infant (unless something makes it clear that they ARE all related!)