Concepts, Categories

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Concepts, Categories Cognition
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What is a Concept?

• Examples
• Triangle
• Dog
• Justice
• A general idea, a class of objects

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Issues in Concept Learning

• How does experience with specific examples lead
  to the formation of a concept?
• How is a concept represented?
• Ideal Form
• Prototype
• Exemplars

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Types of Concepts

• Concepts can be defined by combinations of
  attributes
• A bird is a two-legged, feathered creature with
  wings
• A teenager is a youth between the ages of 13 and
  19
• Concepts can be defined by similarities of
  attributes

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Attribute Combinations

• Simple Attribution
• Object is part of concept if it has Level A of
  Attribute 1
• Male vs. female

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Attribute Combinations

• Disjunction
• Object is part of concept if it has Level A of
  Attribute 1 OR Level A of Attribute 2 (or both)
• good casual eatery - pleasant atmosphere OR
  very reasonable prices
• Conjunction
• Object is part of concept if it has Level A of
  Attribute 1 AND Level A of Attribute 2
• superior restaurant - good food AND good service

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Attribute Combinations

• Bi-Conditional Concept
• Object is part of concept if it has Level A of
  Attribute 1 AND Level A of Attribute 2
• OR
• It has Level B of Attribute 1 AND Level B of
  Attribute 2
• Ex. Good car mechanic

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ATTRIBUTIVE CONCEPT Circular Objects
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ATTRIBUTIVE CONCEPT Blue Objects
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DISJUNCTIVE CONCEPT Blue OR Circular Objects
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CONJUNCTIVE CONCEPT Blue AND Circular Objects
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Biconditional concept Blue AND Square OR Green
AND Circular
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Concept Learning

• Hypothesis testing
• People formulate hypotheses about the concept and
  test them with specific examples
• Prototype Formation
• People develop a prototype of the concept from
  seeing multiple examples
• Exemplar Learning
• People simply learn about the specific examples
  of their experience

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Prototype Formation

• Difficult to study with simple geometric stimuli,
  which have such discrete features
• Michael Posner developed a random-dot prototype
  to study the extraction of prototype information

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Prototype
Exemplar 1
Exemplar 2
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Exemplar Learning

• Implicit Learning through exposure to Exemplars
• How does one keep track of the specific details
  of an experience?
• The configural cue problem

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How Would You Describe an A

• List of features
• left slanted line
• right slanted line
• short horizontal dash
• acute angle

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How Would You Describe an A

• List of features
• left slanted line
• right slanted line
• short horizontal dash
• acute angle

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The Problem of Faces

• What are the features of a face?
• How would you describe someone so they were not
  confused with someone else?

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A demonstration of how to change a face
http//www.stir.ac.uk/staff/psychology/pjbh1/facep
cas1.htm
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Organization of Concepts

• Basic Level
• Dog
• Chair
• Superordinate Level
• Mammal
• Furniture
• Subordinate Level
• German Shepherd
• Rocking Chair

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Need for Models of Cognition

• Empirical results are open to multiple
  interpretations
• In a model, all the details are put together in
  one place

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Types of Models

• Computational Models
• Simon Newell, GPS
• Neural Network Models
• McClelland Rumelhart, PDP
• Matrix Models
• Estes