Lecture 2.docx

Lecture 2 intermodal perception the coordinated perception of a singular object/event through 2 or more sensory systems often vision and at least one other sensory modality intermodal perception is present very early on study: combining vision and touch, question: can newborns integrate vision...

Lecture 2 intermodal perception the coordinated perception of a singular object/event through 2 or more sensory systems often vision and at least one other sensory modality intermodal perception is present very early on study: combining vision and touch, question: can newborns integrate vision and touch? infants sucked on a pacifier they couldn't see preferential looking procedure: picture of the pacifier they had sucked on versus picture of a pacifier of a different shape and texture results of study: combining vision and touch newborns looked longer at the pacifier that they had sucked on - they looked at the familiar pacifier shows that the ability to combine visual information with touch is present at birth study: combining vision and auditory info, question: can infants combine vision with sound? preferential looking procedure: 4 month olds simultaneously watched two videos side by side video of someone playing peakaboo vide of someone playing drums at the same time, they heard audio of a person saying "peekaboo" (audio is synched with only one video) results of study: combining vision and auditory info looked more at the person playing peekaboo versus the person playing drums - because of the familiarity effect shows that infants can integrate visual and auditory info important for language development because children need to understand that speech sounds are linked with a moving mouth reflexes innate, involuntary actions that occur in response to a particular stimulation reflexes are adaptive most disappear by 2 months of age some don't (like coughing, sneezing, blinking, withdrawing from pain) absent reflexes/reflexes that persist for too long can mean the infant has neurological problems examples of reflexes seen in infants grasping: evolutionarily, helped us hang on to branches/caregivers rooting: adaptive for feeding sucking: adaptive for feeding stepping: if you hold newborn up and hold their arms function of some reflex = unclear... tonic neck reflex: when an infant's head is turned to the side, their arm on that side extends and the arm on the other side flexes but if reflexes are missing, could be a sign of a problem in infant's neurodevelopment motor milestones in infancy major motor developmental tasks of a period happen in a predictable sequence, rarely out of order huge individual variation in the ages these milestones are achieved when do babies begin crawling? 7-8 months of age crawling isn't considered a motor milestone - many healthy babies don't crawl and skip right to walking why? upper body/core weakness hypersensitivity to texture of the floor tonic neck reflex is still present insufficient opportunity cultural differences in motor development average age of milestones are based on WEIRD samples, but only 15% of the world's population is WEIRD western, educated, industrialized, rich, democratic cultural practices lead to individual differences in when motor milestones are achieved ie. culture and sitting culture and sitting example of a cultural difference in motor development huge cross-cultural differences in how long 5 month olds can sit independently why? related to where infants are placed to sit ie. little postural support: ground, adult furniture OR lots of postural support: child furniture, baby held by adult EARLIER independent sitting in countries where infants spend more time in places with less postural support (Kenya, Cameroon) LATER independent sitting in countries where infants spend more time in places with lots of postural support (Italy, Argentina) culture and encouragement of motor skills motor milestones = affected by how many opportunities infants have to practice and how much motor development is actively encouraged ie. in some countries, some infants are actively discouraged from crawling because of safety/hygiene - so they crawl later, or never crawl (urban China) ie. motor exercises in sub-Saharan Africa: infants are more advanced in motor skill development than kids in NA culture, diapers and walking diapers affect infant walking infants show more mature walking when naked versus when wearing a diaper all infants were used to wearing a diaper, but when tested were either naked, wearing a disposable diaper or wearing a cloth diaper diapers may contribute to cross-cultural differences in walking motor development: implications of cultural differences cultural practices in one domain can have unintended consequences in another domain context plays an important role in motor development differences in the course of motor development reflect the contexts in which infants are developing differences in crawling different babies crawl differently lots of different styles why is there so much individual variation in when babies achieve motor milestones? environment and genetics early view of motor development until 20-30 years ago, people thought the only thing that governed motor development was BRAIN/CORTICAL MATURATION current theories of motor development motor development is governed by complex interplay between numerous factors neural development increases in physical strength physical abilities, like postural control and balance perceptual skills change in body proportions and weight motivation all these factors contribute to individual differences in motor development motor development: role of weight change infants = born with stepping reflex that disappears at 2 months but then start stepping again between 7-12 months of age when learning to walk why does stepping reflex disappear? hypothesis: infants gain weight faster than they build leg muscles and thus have insufficient strength to raise their legs evidence for role of weight change in disappearing step reflex young infants who still showed stepping reflex stopped stepping when weights were attached to their ankles infants who no longer show stepping reflex resumed stepping when placed in a tank of buoyant water not about brain maturation - it's about muscle strength role of motivation in motor development infants are highly, intrinsically motivated to explore and learn persist despite failing continue to practice new skills even though they possess skills that are more efficient that could accomplish the same goal ie. practice walking even though they could just crawl look delighted when practicing new skills role of motivation: motor development individual differences in motivation predict when motor milestones are achieved study: compared low and high motivation infant on when they achieved motor milestones LOW MOTIVATION INFANTS: movements occur infrequently, prefer activities that require little energy, require lots of stimulation to change position HIGH MOTIVATION INFANTS: move often, prefer high energy activity, change position often, don't need clear stimulation to move results: highly motivated infants achieved all motor milestones earlier than the less motivated infants why does motor development matter? psychological standpoint: means that infants are becoming more and more autonomous have more say over what they are doing - can now act on the world, have more choice and say can experiment - learn by trial and error increases learning opportunities ALSO facilitates development of skills in other domains (esp vision and social behaviour) motor development and visual development crawlers and walkers see the world differently motor development and perceiving 3D objects reaching enables object exploration, which has consequences for visual development 7 months: able to sit independently and to reach allows kids to become more familiar with the properties of diff objects, including 3 dimensions adults do 3D object completion: see objects as 3D even tho the eyes only see in 2D study: motor development and perceiving 3D objects, question: does independent sitting and reaching facilitate understanding of 3D objects? habituation paradigm with 4-7.5 month olds assessed sitting and reaching ability habituation: presented with rotating object with only 2 sides visible get bored complete test display: presented with complete test display: saw each side of the object incomplete test display: more shapes, but not 3D if the baby understands that the go shape was a complete, 3D object, they should look longer at the new incomplete test display results for study: infants that were more advanced in sitting and reaching were more likely to look at the incomplete display age didn't relate to where the infant looked suggests that motor skill development in sitting and reaching influences the development of 3D object perception motor development and depth perception motor development impacts depth perception study: infants were placed in front of walkways with either shallow or steep slopes, and were encouraged to crawl across can babies tell the difference between slopes/detect the difference depths? perception of slope depended on crawling experience beginner crawlers (about 8 months) confidently went down the shallow slope AND also attempted slopes that were too steep experienced crawlers avoided steep slopes when these same babies started walking, they made the same mistake as with crawling initially went down slopes that were too steep failed to transfer what they had learned about slopes through crawling to walking suggests that infants have to learn through experience how to integrate perceptual info with each new motor skill they develop scale errors attempts to perform an action on a miniature object that is impossible due to the huge difference in size between the child and the object present until around 2 years of age due to failure to integrate visual info with action planning study: motor development and social behaviour - understanding intentions adults proactively shift their gaze to the goal of an action when observing somebody performing that action indicates that they understand the person's intention can infants do the same thing? study: eye tracking in adults, 12 month olds and 6 month olds showed video of a person placing objects into a bucket results: adults and 12 month olds showed proactive gaze shift - before the person reached the bucket, they would look there 6 month olds did not look: haven't yet developed ability to pick up, carry and drop objects means that motor development affects things that are seemingly completely unrelated to motor development