Concepts and Knowledge

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Concepts and Knowledge

• Thomas G. Bowers, Ph.D.
• Penn State Harrisburg
• 2000

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Concepts and Knowledge

• We are now moving away from episodic memory to
  information
• Described as semantic memories
• Or, sometimes, context-free or generic memories

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Concepts and Knowledge

• What is a dog?
• What we know is similar to a dictionary
  definition
• The definition itself is not completely adequate

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Concepts and Knowledge

• More difficult concepts
• What is schizophrenia?
• What is truth?
• Or virtue?
• Wittgenstein (1953) wrote at length on the
  philosophical nature of these questions

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Concepts and Knowledge

• Game is a good example of a concept which does
  not allow ready definition
• Question How do we decide about a concept?

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Concepts and Knowledge

• Use Family Resemblances
• Fuzzy logic or fit
• There may be no definition
• No necessary conditions (shared by all)
• Or sufficient conditions (unique attributes)
  

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Concepts and Knowledge

• Prototypes are an alternative to definitions
• An average or representative member of a class
• Marked by fuzzy boundaries
• Graded degree of membership
• i.e. a degree of dogginess

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Concepts and Knowledge

• How to test the prototype notion?
• Sentence verification task
• Assesses processing speed for categorical task
• For example, A chair is furniture or A collie
  is cat

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Concepts and Knowledge

• Subjects are faster for true sentences
• Subjects are faster for familiar categories
• Subjects are slower for atypical examples

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Concepts and Knowledge

• We can also use a production task
• Simply name as many birds as you can, as quickly
  as you can
• Look for convergence with reaction time tasks

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Concepts and Knowledge
Typicality Ratings of Fruit and Bird
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Concepts and Knowledge

• Convergent evidence for prototypes
• 1. Sentence verification tasks (McCloskey
  Glucksberg, 1979)
• 2. Production (Barsalou, 1985)
• 3. Picture identification (Smith, Balzano
  Walker, 1978)
• 4. Explicit memory of membership (Rosch, 1975)

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Concepts and Knowledge

• Convergent evidence for prototypes
• 5. Induction - Inferences from typical to the
  whole, but not from atypical to whole
• 6. Thinking about categories

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Concepts and Knowledge

• Prototypes as heuristics
• There may be gains in cognitive efficiency and
  economy
• Problems can be solved by step by step algorithm
• Tedious, exhaustive, consider and rule out all
  choices
• Heuristics - consider only general plan or
  strategy
• Efficient, may overlook possibilities

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Concepts and Knowledge

• Schema theory revisited
• There is thought to be a network of associations
• Related to each other by propositions
• There is a network of relationships

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Concepts and Knowledge
Dog
Action
Agent
Chase
Object
Cat
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Concepts and Knowledge

• More complex analysis is possible
• Some theories attempt to take into account
  complex human relationships
• Object Relations Theory