Results: 2 1/2-month-olds look reliably longer at the Inconsistent event
Renée Baillargeon
Piaget studied manual search--this may underestimate competence:
- manual abilities may be poor
- may not understand how to search (but understand objects)
- motivational factors
Looking time as a measure of reactions to "possible" and "impossible" events
Violation-of-expectation:
- possible event is consistent with the belief or expectation examined in the experiment
- impossible event violates this belief or expectation
If the infant possesses the belief, they should find the impossible event novel or surprising and therefore look longer at the impossible than at the possible event.
- objects continue to exist when masked by other objects
- objects cannot remain stable without support
- objects move along spatially continuous paths
- objects cannot move through the space occupied by other objects
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Habituation Events |
Short-carrot event
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Tall-carrot event
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Test Events |
Possible event
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Impossible event
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How development proceeds:
"...infants are not born with substantive beliefs about objects (e.g., intuitive notions of impenetrability, continuity, or force), ...but with highly constrained mechanisms that guide the development of infants' reasoning about objects."
Barrier phenomena:
- 4.5 month-olds show surprise when screen falls unhindered
- not good at predicting where it should stop
- 6.5 month-olds detect 80% violation (157 degrees vs 180)
Habituation Event
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Possible Event
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Impossible Event
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Support phenomena:
- by 3 months, infants expect the box to fall if it loses all contact with the platform
- by 6 months, infants expect the box to fall unless a significant portion of its bottom surface lies on the platform
Possible Event
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Impossible Event
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Collision phenomena:
- Habituate to medium-sized cylinder hitting and causing "bug" to roll to the middle of the track
- possible: large cylinder causes bug to move to the end of track
- impossible: small cylinder causes bug to move to the end of track
- 2.5 month-olds: bug should remain stationary when not hit and should move when hit
- 6 month-olds: bug should roll farther when hit by big cylinder not small one
| Habituation Event |
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| Possible Event |
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| Impossible Event |
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Does this reflect an innate understanding of object permanence? If so, then:
- Infants should succeed at detecting all equally salient violations of a given principle (an object cannot pass through another object and a large object cannot pass through a small gap).
But this is not the case. Instead, infants detect certain types of violations before others.
- Infants should succeed at detecting a violation of a given principle in different physical events (a large object cannot pass through as small gap or into a small container)
But they don't -- they understand unveiling and rotating screen events at much different ages even though it's the same principle. Thus, infants "respond to physical events not in terms of abstract principles, but in terms of concrete categories corresponding to specific ways in which objects behave or interact."
Innate learning mechanisms are responsive to experience: Order of acquisition of categories depends on the content of the infants' daily experiences.
References
Baillargeon, R. (1994). How do infants learn about the physical world? Current Directions, 3, 133-140.
Piaget, J. (1964). Development and Learning. In R. Ripple & V. Rockcastle (Eds.), Piaget Rediscovered (pp. 7-19). Cornell University Press.
Piaget, J. (1980). The psychogenesis of knowledge and its epistemological significance. In M. Piatelli-Palmarini (Ed.), Language and Learning (pp. 23-34). Cambridge, MA: Harvard University Press.
Spelke, E.S. (1991). Physical Knowledge in Infancy: Reflections on Piaget's theory. In S. Carey & R. Gelman (Eds.) The Epigenesis of Mind: Essays on Biology and Cognition (pp. 133-169). Hillsdale, NJ: Erlbaum.
© 2001 Dr. Chris Lalonde
Last update: 3 September 2001
