Infant Cognition: Object Permanence Slide 2

Front 1

Infant Cognition: Object Permanence
The Problem:

Back 1

perceptual input constantly changing
•  see object in one location, then another!
•  object covered, cover removed, object there

=> for a purely perceptual organism (no cognition)
object would cease to exist!

=> continued existence of object requires an
understanding (a concept) that an object
continues to exist in TIME & SPACE!

Front 2

Infant Cognition: Object Permanence
How do we acquire this concept

Back 2

•  Nativist Solution:!
•  o.p. innate (e.g., Spelke, 1985)!
! ⇒ selected for in evolution!

Constructivist Solution:!
•  o.p. gradually develops with experience !
e.g. Piaget, 1936/1953)!
!⇒ visual or motor!
Piaget and representation:
-  first true sign at 18-24 months
-  no direct perceptual information available
-  requires stored representation!
Note: errors in search =>!
reveal deficits in knowledge!

Front 3

Piaget’s Substages

Back 3

Before 6-7 months:
- infant plays with toy, toy covered with cloth
- infant doesn't recover toy even if a portion of toy is
visible underneath cloth

•  6-7 months:
- infant searches for partially hidden (occluded) toy
- infant doesn’t search for totally hidden toy

•  8-9 months:
- lifts cloth even when object totally hidden (occluded)
- but makes A not B error

Front 4

Why make this error? Piaget

Back 4

don’t have full understanding of O.P. yet
- errors in search reveal errors in understanding
- egocentrically associate object with their actions at a location

Front 5

Why make this error? Others

Back 5

may have full understanding but other things get in the way
- Means-end reasoning?
- Memory? (Diamond 1985, Diamond )
- but still make error with transparent containers (Butterworth 1975)

- Inhibition/habit? (Diamond 1985)

- but more errors when containers far apart than close - yet habit should be the same (Horobin & Acredolo, 1986)

- Attention? (Harris 1989, Ruffman & Langman, 2002)

Front 6

Piaget’s Substages (cont)

Back 6

•  12-18 months:
- no longer makes A not B error
- but can't handle invisible displacements
- can represent object continues to exist when invisible
and stationary, but not when invisible and moving

•  18-24 months:
- can handle invisible displacements
- now has full object permanence
- representation rather than mere perception

Front 7

Problems for Piaget?

Back 7

habituation/dishabituation violation

Front 8

Occluded Sections of Objects
•  Kellman & Spelke (1983)

Back 8

- only works if object:
(a) moves, b) both parts move in same direction
- findings contrary to Piaget's time scale
=> (4mth olds not look for object under cloth yet
can do this task)
=> newborns look more at the connected rod,
not fill in missing section, not perceive as connected

Front 9

Totally occluded
•  Baillargeon (1985, 1987)

Back 9

- 3.5 to 4.5 months olds
- look more at the impossible (180 deg) event
than the possible or control (112 deg) event

- evidence for object permanence, solidity of objects
(one can't pass through another)

Front 10

Totally occluded
•  Aguiar & Baillargeon (1999)

Back 10

effect shown for very young babies
- 2.5 months (10 weeks)
- youngest evidence for object permanence (?)

Front 11

Totally Occluded: Anticipatory Looking• 

Ruffman, Slade & Redman, 2005

Back 11

Infants trained to expect a hand to reach through one of two doors to retrieve an object hidden behind transparent screens, after prompt (“doors up, here comes the hand!”)
–  Infants see an object hidden behind one of two opaque screens.
–  Infants hear the prompt (after 2 secs or 8 secs) but no hand actually appears

Front 12

Ahmed & Ruffman, 1998

Back 12

looking time verses reaching !
!=> within subjects!
!=> search: correct or incorrect (error)!
!=> non-search: possible (retrieved from B)!
! impossible (retrieved from A)

Front 13

So why the difference between looking and
reaching tasks: Two Theoretical Positions

Back 13

Some think baby does have concept (knowledge tapped in looking and reaching tasks is conceptually identical) but other things interfere => ancillary deficits
•  Means-end reasoning – have to work how to get object
•  Attention – search can get distracted, less so with looking
•  Memory – looking is recognition, search is recall (harder)
•  Inhibition – may not be able to stop previous search (A not B)

Front 14

So why the difference between looking and
reaching tasks: Two Theoretical Positions

Back 14

Some think baby has doesn’t have full understanding but only
partial knowledge (knowledge tapped in looking tasks is
fundamentally different to the knowledge used in reaching)
•  Implicit (unconscious) vs explicit (more conscious) understand ing
=> Looking taps implicit, reaching more explicit understanding
•  Graded representation (concept develops in gradual stages)
•  Gets fuller (Piaget) or gets stronger (Munakata 1998)