Unformatted text preview: Cognition in infancy Cognition focus: objects Conceptual development in infancy
Focus: children’s understanding of children’ objects and object mechanics Rube Goldberg 1 Rube Goldberg 2 How do we measure what very young infants know?
– – Ask them Observe them… them…
1. 2. 3. 4. Exploring the world Reaching for things Attending to things Expectations about things 1. Exploration 1. Requires that infants are crawling. Requires Can be used to study the development of Can knowledge related to exploration/ locomotion itself.
Recall visual cliff studies of fear of heights Recall In this 2nd example, we see how knowledge of In safe and risky ground does not generalize when the baby learns new modes of locomotion. 2. Manual search Another technique relies on infants developing capacity to Another reach and search for objects. This method was the cornerstone of Piaget’s investigations This Piaget’ into early knowledge about objects. Piaget asked when children first start to understand basic Piaget facts about the objects in the world around them. Key idea: “The object concept” concept”
Object Permanence Object
– Objects continue to exist, even when unobserved Retention of physical properties Retention
– Objects retain their solidity, texture, size etc. Retention of spatial properties Retention
– Inanimate objects tend to remain in their locations Piaget’s theory was that infants took a long time to Piaget’ theory construct a concept of objects. Piaget: Evidence for gradual construction Piaget: of object concept
Substage Stage 1 Stage 2 Stage 3 Age (mo) 0-1 1-3 3-8 Description Passive No search; loss of interest when object is hidden. Reach for partially hidden object. No reaching for fully hidden object. Searches for hidden object A not B error Stage 4 8-12 Piaget’s interpretation: Piaget’
Failure to search for hidden objects before 8 months was Failure because infants thought the object was no longer there. They did not understand the object is a permanent entity.
– Infants had not separated the existence of the object from their own perception of it. perception A not B error between 8-12 months was because infants not 8thought the object can be re-created by their reaching for it. re– Infants had not separated the existence of the object from their actions on it. Challenging Piaget’s interpretation: Piaget’ Hints from infants attention during search
Infants often look at correct location, while reaching for incorrect one: 3. Using infant visual attention
Even less demanding than reaching. Even Different measures are available: Different
– What do infants prefer to look at? (Recall tracking of faces experiment) = preference – But if no preference, can infants still discriminate? Use short term habituation to find out. – Do infants have expectations about the way the world works? Show them things that don’t conform: violation don’ of expectation Habituation: making infants bored Habituation: If infants don’t show a preference, If don’ it might be because either:
1. They can discriminate the stimuli but have no preference 2. They cannot tell the stimuli apart. We can use “habituation” to tell We habituation” which Habituation: (baby “getting bored”) bored”
criterion set baby ‘habituated’ Looking time 1 2 3 -3 -2 -1 Trial number What happens when we change the What stimulus? Old ‘control’ New ‘experimental’ Dishabituation = baby “getting interested again”. again” Looking time new - experimental old -- control 1 2 3 -3 -2 -1 Trial number Test phase Using habituation to test infants’ concept infants’ of hidden objects (Rennee Baillargeon)
Habituation phase: 1. 2. 2. 3. 3. 4. 4. 5. Baby shown a ramp and a track. Screen lifted to show nothing hiding on the track. Screen lowered again. Car rolls down ramp, along track, behind ramp, and appears from other side. Repeat until baby bored. Test phase: ‘possible event’ Critical difference: placement of box behind or on track track Leads to events being seen as possible or impossible Test phase: ‘impossible event’ DEMO: Summary
These results demonstrate that infants have object These concept long before claimed by Piaget. Habituation and violation of expectation can be Habituation used as windows into a vast array of physical and other knowledge in infancy.
– For example: demonstrations of knowledge about motion across space and time. Infants appear to start out Infants with a core knowledge of certain principles that govern the physical world. But this knowledge is not But complete adult knowledge. They gradually elaborate this core – learning about other rules as they interact with and experience the world. So if infants know so much about So objects, why can’t they find them? can’ Why search errors? Why These abilities are revealed in visual attention tasks, but These not in reaching tasks (e.g., manual search)?
– Demands of reaching tasks higher. – Memory, attention, habit, learning from communicative cues – Distinction between ‘competence’ and ‘performance’ competence’ performance’ Next time
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- Fall '08
- Developmental Psychology