Infant Perception II Last class C Fear of heights Visual cliff deep and shallow sides I Face Perception II Categorization III Depth Perception we will finish today Today IV Object Segregation V Cross Modal Perception VI Conclusions Results Campos et al 2 groups Experienced crawlers 9 mos Beginning crawlers 7 mos 15 per group Experienced 15 15 cross shallow 0 15 cross deep Beginning 15 15 cross shallow 10 15 cross deep most Related results Babies in harness go off a high table Rader et al Initial Interpretation Beginning crawlers have depth perception but NO fear of heights Phone survey of parents babies crawl off high surfaces e g tables couches beds changing tables How does fear develop Falls and near falls Social referencing 1 Uncertainty with 12 inch drop Certainty with 40 inch drop infants use social referencing infants ignore parent posing joy if parent poses fear infants don t cross deep side infants don t cross deep side if parent poses joy infants cross deep side with 4 inch drop infants ignore parent posing fear infants cross deep side Autonomous thinkers Kretch Adolph reading New Interpretation Focus 90 cm drop Campos Beginning crawlers have depth perception but NO fear of heights but new evidence by Adolph assigned reading article suggests a somewhat different conclusion 12 month old experienced crawlers do not crawl into drop confirms Campos BUT Infants do not learn fear of heights once and for all Rather infants learn what is safe vs unsafe for each posture e g sitting crawling walking separately 12 month olds novice walkers walk into drop 18 month olds experienced walkers do not walk into drop D Conclusions IV Object Segregation Young infants have some depth perception at birth Where does each object begin and end How well they see depth depends on cues available in a scene Infants learn implications of depth e g drop off separately for each posture 2 A Adults many sources of info one such source is Partly occluded display Featural information e g shape pattern color texture etc If surfaces on either side of the screen have the same features then same object Partly occluded display If surfaces on either side of the screen have different features then different objects 3 Violation of expectation Method B Infants Show two test events Needham et al 4 mos expected consistent with expectation unexpected violates expectation If look reliably longer at unexpected event have expectation Similar Condition Move Together Event Results look reliably longer at apart than at together event see red surfaces as 1 box Move Apart Event Assume similar features mean one object Dissimilar Condition Results Move Together Event look reliably longer at together than at apart event see red and green surfaces as 2 boxes Move Apart Event Assume different features mean different objects 4 III Cross modal Perception C Conclusions By 4 months use featural info to organize visual scenes However not at 3 months infants learn to use featural info to organize visual scenes between 3 and 4 months A Do newborns orient toward sounds Yes as long as Focus Auditory visual perception B Do infants know what sights and sounds go together Spelke and Owsley 3 5 mos and older Play mom s or dad s voice on speaker held properly sounds not too intense sounds not too brief MOM DAD MATCH voice to parent BABY Kuhl and Metzolf 4 mos See silent videotapes of same woman saying a or ee Hear a or ee on central speaker C How do infants attain their auditory visual knowledge Association Anything else Adults can detect synchrony MATCH sound to face Can infants also extended to 2 months 5 Spelke 4 mos Predictions If only association ZIP slow fast If can detect synchrony MATCH soundtrack to movie Fam 100 sec Donkey soundtrack 100 sec Kangaroo soundtrack Test several 5 sec segments of Donkey Kangaroo soundtracks Example of other events Lewkowicz and Ghazanfar Results at 4 and 6 months infants can match vocalization and face of rhesus monkey MATCH each soundtrack to its movie fail at 8 and 10 months because of perceptual narrowing in processing of cross species faces vocalizations or both Can detect synchrony Extended to many other events long coo affiliative encounter short grunt threat call VI Conclusions Infants perceptual world is not fundamentally different from that of older children and adults From birth they possess a rich set of perceptual abilities that are elaborated fine tuned and shaped by experience But do infants think about the world as we do Is their cognitive world qualitatively similar to ours or is it fundamentally different The developmental researcher who first promoted the idea that infants and young children are fundamentally different thinkers than older children and adults was the Swiss psychologist Jean Piaget We now turn to a discussion of his influential theory on cognitive development Next we will examine how Piaget s theory has been revised over time 6 Piaget s Theory I Background II A stage theory III The pre operational stage Why such impact created the field of cognitive development produced very broad theory age range infancy to adolescence topics all aspects of cognition e g causality time space logic categorization concepts symbols imagination play moral judgment Three radical claims 1 Child plays active role in knowledge acquisition Constructivist view not a vessel in which society pours knowledge moral norms etc against Freud I Piaget s theory Background Personal details 1896 1980 Switzerland 1918 Ph D in zoology 1919 1920 went to Paris to study psychology hired in Alfred Binet s lab to give IQ tests to children 1921 back to Switzerland to start his life s work married 3 children Why such impact cont d found tasks that were easy to do and that replicated with children around the world made radical claims about the process of cognitive development Three radical claims cont d 2 Major qualitative discontinuities in cognitive development Stage view children are fundamentally different thinkers than adults not a passive entity e g ball of clay shaped by rewards and punishments against Skinner 7 II A Stage Theory Three radical claims cont d 3 No innate cognitive basis to development against Chomsky only general tendencies for adaptation and organization these tendencies are shared with all other animals What does it mean to have stages Universal sequence of 4 stages sensorimotor 0 2 yrs pre operational 2 7 yrs concrete operational 7 12 yrs formal operational 12 2 Development is discontinuous