Module 4_ Chapter 8_ Perception and Knowledge of the World.pdf

Module 4: Chapter 8: Perception and Knowledge of the World Knowledge of Objects Object Search and Object Permanence -from 6-8 months infants begin to search for hidden objects! -Jean Piaget found that at the 8-month mark, an infant will almost immediately retrieve a toy that has been hidden from the...

Module 4: Chapter 8: Perception and Knowledge of the World Knowledge of Objects Object Search and Object Permanence -from 6-8 months infants begin to search for hidden objects! -Jean Piaget found that at the 8-month mark, an infant will almost immediately retrieve a toy that has been hidden from them: “object permanence” -8-12 months: a-not-b error persists -after 12 months: search errors occur on more complex tasks, with more complex sequences of object hiding and displacement Violation of Expectation and Object Permanence -T. G. R. Bower’s studies of infant object knowledge in the 1960s-70s: -measured infant anticipation of the reappearance of objects from behind screens -violation of expectation technique (1980s): -familiarization trial that moves into -> 1) the possible, expected test scenario of the object moving and 2) the impossible test scenario of the object moving -if the infant knows that 1) moving objects continue to exist behind a screen and 2) one object cant move through another, = their expectations should be violated and they will show signs of confusion and/or distress. They will also look longer at the impossible event -have to be cautious! Infants look longer at novel stimuli, so this must be avoided when creating the “impossible” event in some way -Baillageron’s truck and ramp study: the possible and impossible events are identical when the screen is lowered (truck -> rolls down ramp -> disappears for a moment -> emerges out the other side), ruling out the possibility of looking longer at the impossible event due to novel stimuli -6-8 month olds look longer at impossible event (later replicated with 4 month olds) -The Drawbridge Study: -5 month olds looked longer at the impossible event, evidence that young infants can understand object permanence (they knew the cube was still present once hidden by the drawbridge) and that one object cant move through a space occupied by another -Innate Core Knowledge: -these accounts contradict Piaget’s beliefs of infant object knowledge -these accounts would be considered “nativist”, that object knowledge/permanence is innate -however, nativists dont claim that all knowledge is innate knowledge; the recognize that innate knowledge can and must be built upon to achieve a more accurate understanding of the world -infants and support relationships: for young infants, any above-below contact between two objects is enough to support the object above. As they get older, they require more of the above object be supported, and then require that the below object be close enough to the above object’s centre of gravity to prevent the above object from toppling. -Infants Reason about Events: -nativists argue that infants use core knowledge to help them reason about the real-world events they encounter -E. S. Spike et al. continuous/discontinuous task: the infants who had been familiarized with the continuous event looked longer at the two-object display, and infants familiarized with the discontinuous event looked longer at the one-object display -What does this mean?? On the basis of what they saw during familiarization, infants reasoned that either one or two objects were involved in the event and looked longer at the display that violated their familiar reasoning (why do there seem to be two rods now when I determined there was only one before??) Alternative Accounts of Search Failure and Search Errors -these two bodies of data present a conflict!! -on one hand: evidence that infants dont begin search for hidden objects until 6 months, and even then often display a-not-b error -on the other hand: violation of expectation studies suggest 3-4 month old infants can already understand object permanence and reason about events -we know search failure isnt due to an inability to organize the action; maybe the search task is imposing an additional (cognitive?) load in other aspects! -Memory Limitations?? -do infants make search errors because the cognitive load of memory is too great? The answer is maybe, maybe not -6-month olds have been shown to be successful in tasks when the hidden object is under a transparent cover, eliminating the memory load, and are more successful as they get older and develop more sophisticated memory abilities while tolerating longer delays between hiding and searching -on the other hand, infants have also been shown to make a search error even when an object is in clear view in the “B” hiding place -contributions to the memory limitations to the a-not-b error remains unsolved -Response Preservation? -some have suggested the a-not-b error is due to response perseveration; the infants form a response habit of reaching for the object at the “a” location -if this were the case, infants should correct the action right away; but they often do not -infants make the a-not-b error even without reaching for the object at the “A” location but simply watching it covered and uncovered there, so this is evidence against the response perseveration -Different Levels of Knowledge? -infants may have enough awareness to look longer at the impossible event in violation-of-expectation tasks, but not enough to accurately guide their actions in search tasks Infants’ Spatial Awareness Spatial Orientation -do infants possess spatial orientation skills, and is there evidence for the development of spatial skills during infancy? -The Peekaboo Paradigm -most common method of assessing infants’ spatial orientation abilities -infants are set up in a circular surround and an investigator pops up at different places. The infant is then moved to face a different way and tested to see if they accurately predict where the investigator should pop up relevant to their new position. -to avoid a response perseveration, infants are given training trials from two diff directions of facing and then tested for anticipation from a third direction of facing -4-8 months: infants show an increasing ability to take account of bodily rotation, performance is improved by the presence of a distinct visual landmark at the event location -6-8 months: infants can make use of the relationship between landmarks -Acredolo: older research suggests that between 9-18 months infants show reduced reliance on direct landmarks to take bodily movements into account -A Link with Crawling? -once infants can sit unaided at ~6 months, they develop control of rotational head and trunk movements (similar to the ones used in the peekaboo task) -a few months after 6 months, when infants can crawl, they gain control over bodily displacements and rotations of the sort used in Acredolo’s task -^ these developments (or lack thereof) might be connected with how infants perform these tasks when tested! Perception of Depth and Wariness of Drops -Piaget argued that infants aren’t initially aware of the 3-dimensional world, and have to construct this understanding through actions -studies show consistent findings with this idea -5 months: infants are less likely to reach for an object that is closer to the horizon, assumed because they believe it is farther away than it is. They also don’t seem to use shadows in their perception of depth -7 months: infants begin using shadows in their perception of depth -crawling would help infants understand depth and distance through action -there is an alternative account that infants DO perceive the third dimension from birth -A Classic Study: The Visual Cliff -Gibson and Walk’s study showed that of the 27 infants aged 6-14 months that were tested, only 3 ventured over the visual cliff. All of them crossed the “safe” shallow side. -is this evidence for innate depth perception? Perhaps not. The youngest infant was already 6 months old, and innate knowledge is usually tested when an infant is no more than 2-3 months old. Infants can learn a lot in 6 months -Using Heart-Rate Change to Measure Wariness -visual cliff altered; 5 month old infants (pre-crawling) showed a deceleration in heart rate when measured into the deep part (interest), and 9 month olds showed an increase (stress, unease); the younger infants perceived the diff between deep/shallow areas but only the 9 month olds showed wariness of the drop -Crawling Experience and the Development of Wariness -even when tested with infants of the same age, crawlers showed more wariness than non-crawlers. However, even the crawlers of the same age might be more cognitively advanced -even when controlled for age AND cognitive ability, experience crawling and/or walking seems to determine whether or not the infant will cross the deep side -Depth Perception vs Wariness of Drops -even newborn infants seem to understand size constancy, which suggests that Gibson and Walk were right in their view that depth perception was innate -this suggests that infants may be aware of the depth difference in the visual cliff before they can crawl, but only those with more crawling experience understand they should be wary of the drop -it is unlikely that wariness is due to falling in experience; parents take great caution to protect their infants from this. Rather, it might be due to the change of visual flow in their word that the sudden drop presents (they see this as new and potentially not safe) -social referencing; infants might also learn the emotional responses to danger from their parents and in turn learn to be wary of these drops an dangers this way