Categorization and Concept Development

n    How do you know these are all cats?

Or all of these are animals

 

n    Classic view of categories was that they could be defined by simple criterial features

n    For example, participants would learn to categorize :

 

 

 

Research by Rosch in 70’s

n    Members of categories are not equally representative but have typicality structures

n    Reaction Times to identify typical items are faster than atypical items

n    Children learn the names for typical items faster than atypical items

 

Research by Rosch in 70’s

n    Members of categories are not equally representative but have typicality structures

 

What about individuals with autism

Category Membership is Determined by typicality

n    Prototype Models (e.g, Homa)

n    Exemplar Models (e.g., Medin, Nosofsky)

How do we learn categories?

n    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

n    Fortunately, infants appear to have inborn mechanisms that help then learn and figure out the world.

n    They innately abstract generalized representations of categories

n   Imagine you’ve never seen a llama before.  Someone shows you 1 then 2, then 3….examples

n   Eventually, you’ll have abstracted a general idea of what llamas look like

What about individuals with autism?

n    While typically developing individuals respond faster to typical than atypical examples, this is not true of individuals with autism.

n    When asked to rate the typicality of items, their conceptions are quite different than controls

n    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?

n    Friendship, love, play?

n    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

n    Research suggests categorization comes prior to language

n   Then why do infants do over-extensions?

n    Does language play any role

n   Maybe for some categories?

n   Way of “motivating” infant to make distinction

Role of perceptual vs. conceptual information

n    Researcher have argued about which is primary

n    Perhaps both simultaneously?

What about quantity concepts?

n    Can infants discriminate discrete quantities?

 

Discrimination of Quantity
Heterogeneous Condition

2 dogs

2 chairs

2 books

2 cars

.

.

3 tables

2 pencils

Results

n    Babies starting at 5 months of age can discriminate quantities of 2 vs 3, 3 vs 4 but not 4 vs 5.

n    Why

Subitizing

Subitizing

n    Cross cultural research: Amzonian Indians

n    What’s it’s function

n   In animals

n   Underlying later skills

Ordinal Abilities

n    The ability to understand more versus less

n   With both continuous and discrete information

 

 

Results

n    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

n    12 month olds are unable to do the task

n   Why?

 

Results

n    With continuous quantities, 12 month olds can do the task

n    What’s going on?

n   Perhaps they’re learning discrete amounts from their experiences with large or long things.

n   Consider Piaget’s number conservation task

 

Can infants add and subtract?

n    Karen Wynn’s study:

 

Knowing the physical world

n    Piaget and other constructivist assumed our knowledge comes from active interactions and explorations of the world

n    This is especially true in infants older than 7 months as crawling develops and infants become more physical capable

n    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.

n    An alternative position is that babies are observing from an early age and developing expectations

Leslie’s Causality

n    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

n     Habituate to: Contact and Immediate (Casual)

 

Test

n    No Contact and Delay (Non- Casual)

Causality: Studies by A. Leslie

n     Habituate to: Contact and Delay ( Non-Casual)

 

Test

n    No Contact and Immediate (Non- Casual)

Leslie

n    Results:  Infants perceived causality at 7 months

n   While he originally suggested an innate module

n   Is this necessary?

n    Follow-up research by L. Cohen

n   Knowledge is somewhat fragile—small parametric changes will lead to different results

n   Not until closer to 10 months is it robost

Object Permanence

n    R. Bailargeon

 

Object Permanence

Object Permanence

n    L. Cohen has argued that infants are really just more interested in the full screen condition because they have not fully habituated

n    Other’s disagree and believe that there is some innate knowledge of permanence

n    An alternative may be that infants have some visual expectations but conceptually do not understand permanence

 

E. Spelke: Object Solidity

Object Solidity

Again…..

n    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

n    Conclusions?

What is significance of infancy?

n    Period of time where we learn about the “sensori-motor” world