Cognitive Psychology

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Cognitive Psychology

• Part I
• Where does Cognitive Psychology fit within
  Cognitive Science?

2
Just about everywhere.

• Almost all research in Cognitive Science is
  relevant to some Cognitive Psychologist.

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Important Concepts

• Three levels of organization of intelligent
  systems (Pylyshyn, 1999)
• Physical/Biological
• Syntactic/Symbolic
• Semantic/Knowledge

4

• Three levels of understanding information
  processing (Marr, 1982)
• Hardware Implementation
• Representational Algorithm
• Computational Theory

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Computational Theory(knowledge/semantics)

• What is the goal of the computation?

See a brown dog
Pet the brown dog
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Representation Algorithm(Syntactic/Symbolic)

• How to implement these goals?
• How are the inputs and outputs represented?
• What must be done to see a brown dog?
• To pet the brown dog?
• What is the algorithm for transforming one to the
  other?

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Hardware Implementation(biological/physical)

• What physical equipment is needed to implement
  these representations and algorithms?

• Retina(s)
• Interneurons
• Motoneurons
• Muscles
• Arm/hand
• Proprioceptors
• Tactile sensory neurons
• Etc.

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• The three levels (theory, representation
  algorithm, and implementation) are useful
  organizing principles in all of Cognitive Science
• Psychology is mostly concerned with the second
  level Representation and Processing

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Whats not Cognitive Psychology?

• Purely engineering solutions (e.g. Deep Blue
  II)
• Building jet airplanes doesnt help us better
  understand birds

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Reading AssignmentWeek 2

• Pylyshyn, Z. (1999). Whats in your mind? In
  Lepore, E. Pylyshyn, Z. (Eds.) What is
  Cognitive Science (pp. 1-25). Oxford, Blackwell.

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Warning

• Pylyshyn is very biased
• (but not necessarily wrong).
• Opposed to behaviorism (1.11.2, 4.1).
• Opposed to connectionism (In favor of symbolic
  representations) (4.2).

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Behaviorism

• We can only understand an organisms behavior by
  studying physical stimuli and how the organism
  reacts to them.
• It is not possible to observe the internal
  workings of the mind, so dont propose internal
  constructs (goals/desires, mental
  representations, algorithms, etc.)
• Now largely abandoned. In Cognitive Psychology
  it is now common and accepted to postulate
  internal constructs.

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Connectionism

• Computational models of behavior.
• Modeled on the brain (neural networks).
• Do not rely on symbolic expressions.
• Can perform a surprising range of
  computational/behavioral tasks.
• Cant do everything humans can?
• (Fodor Pylyshyn, 1988)

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Part II

• What is Cognitive Psychology?

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Cognitive Psychology

• How
• Experimental
• Biological
• Computational

• What
• Perception
• Categorization
• Representation
• Memory
• Attention
• Learning
• Thought

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Why do experiments?

• Human beings were not created for the
  convenience of experimental psychologists.
  George Miller (in Barsalou, 1992)

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Control the situation

• Most phenomena could have many causes, how do we
  know which one is the (main) cause?
• Test each possibility, one by one.
• Need to eliminate chance of other causes taking
  effect (control)

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Some ways to control variables

• Select your subjects carefully
• Only right-handed, male, native English speakers
• Create your stimuli carefully
• Record specific syllables spoken by a trained
  talker
• Choose a simple environment
• Empty room, sound booth, etc.

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Manipulate your subjects

• Experiments crucially involve a comparison of (at
  least) two groups (who may still be the same
  people).
• The difference between the groups is caused by
  manipulation of experimental variables.

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Some Experimental Manipulations

• Between group comparisons
• 2 year-old children vs. 6 yr olds
• English speakers vs. Cantonese speakers
• University students vs. early school leavers
• Within group comparisons
• Untrained listeners vs. trained listeners
• Listening to Cantonese vs. listening to English
• Dosed with a drug vs. with a placebo

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For example

• Question Does knowing how to speak one tone
  language make it easier to hear the tones of a
  different tone language?
• (easier than it is without knowing a tone
  language)
• Possible answers
• Yes, perception of tone is universal if youve
  got it, youve got it.
• No, perception of tone is language-specific. You
  must learn the sound system of each language
  separately.
• How do we test this?

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Lee, Vakoch, Wurm (1996)

• Three groups Cantonese, Mandarin, and English
  speakers
• Two sets of sounds Cantonese and Mandarin
  (presented in pairs, grouped by language)
• Asked subjects same or different for each pair

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Lee, Vakoch, Wurm (1996)

• Cantonese tones
• Cantonese gt Mandarin English
• Mandarin tones
• Mandarin gt Cantonese gt English
• Conclusions
• Native language is best
• knowing Cantonese helps with Mandarin
• Knowing Mandarin does not help with Cantonese

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Criticism of experiments

• Ecologically implausible
• same-different task is unlike real speech
  perception
• Small answers to small problems
• What do we really know now that we didnt know
  before?

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Bibliography

• Barsalou, L. W. Cognitive Psychology An Overview
  for Cognitive Scientists. Hillsdale, NJ,
  Lawrence Erlbaum and Associates.
• Coren, S. Ward, L. M. (1989). Sensation and
  Perception, Third Edition. Fort Worth, NJ,
  Harcourt Brace Jovanovich.
• Fodor, J. A. Pylyshyn, Z. W. (1988).
  Connectionism and cognitive architecture a
  critical analysis. Cognition, 28, 3-71.
• Goldstone, R. L., Barsalou, L. W. (1998).
  Reuniting perception and conception. Cognition,
  65, 231-262.
• Lee, Y.-S., Vakoch, D. A., Wurm, L. H. (1996).
  Tone perception in Cantonese and Mandarin A
  cross-linguistic comparison. Journal of
  Psycholinguistic Research, 25, 527-542.
• Marr, D. (1982). Vision. New York, W. H.
  Freeman Company.
• Medin, D. L. Aguilar, C. (1999).
  Categorization. In Wilson, R. A. Keil, F. C.
  (Eds.) The MIT Encyclopedia of the Cognitive
  Sciences (pp. 104-106). Robert A. Wilson and
  Frank C. Keil. Cambridge, MA, MIT Press.
• Miller, G. A. (1956). The magical number seven
  plus or minus two Some limits on our capacity
  for processing information. Psychological
  Review, 63, 81-97.
• Pylyshyn, Z. W. (1999). Whats in your mind? In
  Lepore, E. Pylyshyn, Z. W. (Eds.) What is
  Cognitive Science (pp. 1-25). Oxford, Blackwell.
• Shepard, R. N., Metzler, J. Mental rotation of
  three-dimensional objects. Science, 171,
  701-703.
• Stroop, J. (1935). Studies of interference in
  serial verbal reactions. Journal of Experimental
  Psychology, 18, 624-643.
• Wu, L., (1995). Perceptual Representation in
  Conceptual Combination. Doctoral dissertation,
  University of Chicago