Categorization and Concept
Development
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How do you know these are all cats?
Or all of these are animals
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Classic view of categories was that they could be
defined by simple criterial features
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For example, participants would learn to categorize :
Research by Rosch
in 70�s
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Members of categories are not equally representative
but have typicality structures
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Reaction Times to identify typical items are faster
than atypical items
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Children learn the names for typical items faster than
atypical items
Research by Rosch
in 70�s
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Members of categories are not equally
representative but have typicality structures
What about individuals with
autism
Category Membership is Determined by typicality
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Prototype Models (e.g, Homa)
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Exemplar Models (e.g., Medin,
Nosofsky)
How do we learn categories?
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Over last 20 years there have been numerous studies
with infants (e.g., Cohen, Strauss, Quinn, Younger) using habituation paradigm.
How would you come to learn
this �alien� world
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Fortunately, infants appear to have inborn mechanisms
that help then learn and figure out the world.
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They innately abstract generalized representations of
categories
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Imagine you�ve never seen a llama before.� Someone shows you 1 then 2, then 3�.examples
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Eventually, you�ll have abstracted a general idea of
what llamas look like
What about individuals with
autism?
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While typically developing individuals respond faster
to typical than atypical examples, this is not true of individuals with autism.
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When asked to rate the typicality of items, their
conceptions are quite different than controls
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They do not seem to have abstracted what �average�� or prototypical
objects look like.� Their notions of
categories depend on idiosyncratic� details.
What about more abstract
concepts?
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Friendship, love, play?
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We speculate that individuals with autism also do not
abstract generalized representations of these concepts.� Rather, they define them in very detailed,
perhaps idiosyncratic ways.
What is the role of language
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Research suggests categorization comes prior to
language
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Then why do infants do over-extensions?
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Does language play any role
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Maybe for some categories?
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Way of �motivating� infant to make distinction
Role of perceptual vs.
conceptual information
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Researcher have argued about which is primary
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Perhaps both simultaneously?
What about quantity concepts?
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Can infants discriminate discrete quantities?
Discrimination of Quantity
Heterogeneous Condition
2 dogs
2 chairs
2 books
2 cars
.
.
3 tables
2 pencils
Results
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Babies starting at 5 months of age can discriminate
quantities of 2 vs 3, 3 vs
4 but not 4 vs 5.
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Why
Subitizing
Subitizing
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Cross cultural research: Amzonian
Indians
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What�s it�s function
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In animals
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Underlying later skills
Ordinal Abilities
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The ability to understand more versus less
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With both continuous and discrete information
Results
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16 month olds are able to learn task and always pick
the larger (or smaller) quantity.� They
don�t seem to pay attention to the exact quantities
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12 month olds are unable to do the task
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Why?
Results
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With continuous quantities, 12 month olds can do the
task
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What�s going on?
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Perhaps they�re learning discrete amounts from their
experiences with large or long things.
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Consider Piaget�s number conservation task
Can infants add and subtract?
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Karen Wynn�s study:
Knowing the physical world
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Piaget and other constructivist
assumed our knowledge comes from active interactions and explorations of the
world
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This is especially true in infants
older than 7 months as crawling develops and infants become more physical
capable
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Others (e.g., E. Spelke
and R. Baillargeon) have argued that some knowledge
appears very early (4 to 5 months) suggesting an innate basis similar to
Gibson�s views of perception.
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An alternative position is that
babies are observing from an
early age and developing expectations
Leslie�s Causality
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Contact-Immediate to Non Contact- Delay
���� Causal������������������� to���� Non Causal (2 elements)
Contact- Delay� to�
Non Contact- Immediate
���� Non
Causal����� to �������� ��Non Causal (2
elements)
Causality: Studies by A. Leslie
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�Habituate to:
Contact and Immediate (Casual)
Test
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No Contact and Delay (Non- Casual)
Causality: Studies by A. Leslie
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�Habituate to:
Contact and Delay ( Non-Casual)
Test
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No Contact and Immediate (Non- Casual)
Leslie
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Results:�
Infants perceived causality at 7 months
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While he originally suggested an innate module
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Is this necessary?
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Follow-up research by L. Cohen
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Knowledge is somewhat fragile�small parametric changes
will lead to different results
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Not until closer to 10 months is it robost
Object Permanence
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R. Bailargeon
Object Permanence
Object Permanence
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L. Cohen has argued that infants are really just more
interested in the full screen condition because they have not fully habituated
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Other�s disagree and believe that there is some innate
knowledge of permanence
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An alternative may be that infants have some visual
expectations but conceptually do not understand permanence
E. Spelke: Object
Solidity
Object Solidity
Again�..
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L. Cohen has argued and demonstrated that there are
other �perceptual� explanations for the results and that this knowledge does
not exist until 10 months of age
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Conclusions?
What is significance of infancy?
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Period of time where we learn about the �sensori-motor� world