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Abstraction and ACT-R

Abstraction and ACT-R. Outline. Motivations for the Theory Architecture Abstraction Production Rules ACT-R Architecture of Cognition. Architecture. There is a distinction between brain architecture and cognitive architecture.

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Abstraction and ACT-R

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  1. Abstraction and ACT-R

  2. Outline Motivations for the Theory • Architecture • Abstraction Production Rules ACT-R Architecture of Cognition

  3. Architecture • There is a distinction between brain architecture and cognitive architecture. • This is a difference between the physical description of the system, and the functional properties that it enables. • Some examples…

  4. The common feature to each is in the method of abstraction. • Moving from a more complex, lower level system of interaction, to a higher level language in which those lower level features are typed. Some Characteristic features of Abstraction.

  5. Constraints on the Abstraction • Typing • Lower level features are given higher level types • Simplification • The higher level abstraction is obligated to simplify conceptual complexity • Morphism • There must be a mapping. • ‘Many to one’

  6. Production Systems Comprise a language with sentences of the form If <<condition>> then <<event/action>> Developed by Emil Post (1943), also known as ‘Post Production Rules’ Turing Complete

  7. Solve a Linear Equation • If the expression has X = N, where N is a number, THEN halt and check by substituting N in the original equation • If there is a term in X on the right-hand side, THEN subtract it from both sides, and collect the terms. • IF there is a numerical term on the left hand side, THEN subtract it from both sides, and collect the terms • IF the equation has the form NX = M, N = 1, THEN divide both sides by N

  8. If the expression has X = N, where N is a number, THEN halt and check by substituting N in the original equation If there is a term in X on the right-hand side, THEN subtract it from both sides, and collect the terms. IF there is a numerical term on the left hand side, THEN subtract it from both sides, and collect the terms IF the equation has the form NX = M, N = 1, THEN divide both sides by N X = 2X + 5 X – 2X = 2X – 2X + 5 -X = 5 X = -5

  9. ACT-R(Adaptive Control of Thought-Rational) • Modules • Buffers • Productions

  10. Modules - Fodor (Modularity of Mind) • Features • Functional separation Domain specific • Interaction between modules

  11. Buffers • Active Content • Interface • Interaction between modules • Provides the link

  12. Productions • If <<condition>> then <<result>> • State Change • Contents of Buffer • Contents of Modules

  13. Learning • Adaptive control • Update • Goal structures • Declarative memory contents • Productions

  14. Structure of Declarative Module ‘Chunks’ – A collection of related information. Action023: isa chase agent dog object cat Fact3+4: isa addition-fact addend1 three addend2 four sum seven

  15. Summary • Cognitive Science and Act-R benefit by engaging in abstraction • By matches conditions set by contents in the buffer, and specifying to changes in that content. Act-R models cognition.

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