Cognitive Psychology

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Cognitive Psychology
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Cognitive Science as Interdisciplinary
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Classical Statements

• By convention there are sweet and bitter, hot
  and cold, by convention there is color but in
  truth there are atoms and the void
• Democritus, Fragment 9. (Quoted by Sextus
  Empiricus, Adv. Math. vii 135)
• I think that tastes, odors, colors, and so on
  are no more than mere names so far as the object
  in which we locate them are concerned, and that
  they reside in consciousness. Hence if the living
  creature were removed, all these qualities would
  be wiped away and annihilated
• Galileo Galilei, The Assayer (published 1623). As
  reprinted in (Drake, 1957, p. 274 )
• For the rays, to speak properly, are not
  colored. In them there is nothing else than a
  certain power and disposition to stir up a
  sensation of this or that color.
• Isaac Newton, Optics (3rd ed. 1721, original in
  1704). Reprinted in (Newton, 1953, p.100)

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Rene Descartes (31 Mar 1596 11 Feb 1650)

• Recognizing the fallibility of learned, customary
  and habitual ways to coming to know, Descartes
  resolved to conduct a general demolition of
  opinion so as to begin anew, to form an new
  starting point for science, and to discover
  through solitary reflection an absolute limit of
  doubt (like a mathematical fixed point), an
  Archimedean fixed fulcrum (I think ? I am), a
  long lever (Cartesian method of doubt).
• The essence of mind (selfIegosoulâmemens)
  is thinking (not rational thought only, but
  understanding, feeling, emotion, perception,
  dream, doubt, sensation, all consciousness).
  Subjective experience not subject to m
• Judgment is an action of will, not of intellect
  alone
• The essence of matter is extension (primary
  qualities are modes of extensions, as is motion).
  Matter as extension makes up space (vacuum is
  impossible and absurd). Quantitative science
  studies matter in motion
• Terrestrial and celestial matter observe the same
  laws. All body works on mechanical principles.
  Animals are machines, but in a sense have souls
  (animal spirits lta subtle airgt in the blood and
  coursing through nerves). In humans their effects
  on pineal gland account for subjective
  experience, and explain the mechanism of will.
  Pneumatic or hydraulic metaphor of mind acting on
  body

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Drawing by Descartes Object creating an mental
representation

• Notice pencil of rays as if drawing on retina
• Notice inverted 2D image on retina, as in camera
  obscura
• Notice mental representation (subjective idea) in
  the pineal gland (seat of mind)
• Notice assumption of mathematical laws projection
  and perspective.

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The Beginnings of Modern Psychology

• Psychophysics (Weber, Fechner, von Helmholz)
• Opened mind to experiment sought mathematical
  relations between level of subjective experience
  and level of physical energy in stimulus
• Helmholz visual perception involves unconscious
  inference, not mere passive reception
• Perceiver plays an active (if not wholly
  conscious) role in perception current processes
  influence by past ones
• Structuralism (Wundt)
• Metaphor was the periodic table of chemistry
  goal was to describe the structures of thought
• Functionalism (James)
• Emphasis on function of mental processes (vs.
  structure)
• Both Structuralism and Functionalism used
  introspection
• Wundts The method entails observing ones
  thought processes, but it was deemed important
  that a more experienced introspectionist train a
  novice in the method

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Behaviorism
John B. Watson 1878 - 1958

• Psychology as the behaviorist views it is a
  purely objective experimental branch of natural
  science. Its theoretical goal is the prediction
  and control of behavior. Introspection forms no
  essential part of its methods, nor is the
  scientific value of its data dependent upon the
  readiness with which they lend themselves to
  interpretation in terms of consciousness. from
  Watson, 1913, Psychology as the Behaviorist Views
  it.

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What Behaviorism Couldnt Do

• Couldnt deal with ethological principles
  (Lorenz)
• Fixed action patternsComplex behaviors in which
  an animal engages despite very limited
  opportunities for practice or reward. Usually
  taken as evidence for innate or inborn learning.
• Critical periodsA window of opportunity during
  which a particular type of learning will be easy
  for the organism. If the critical period is
  missed, however, the learning will be difficult
  or even impossible.
• Couldnt account for data
• learning without responding
• learning without reinforcement
• evidence for cognitive maps
• complex activities require prior planning (piano
  playing)
• generativity of language production and
  comprehension
• learning has biological constraints (contrary to
  behaviorism)

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Learning Without Responding

• Stimulus the maze. Response turn to right.
  Reinforcement food reward
• But rats driven in carts to the destination were
  allowed no overt response later, now free, they
  showed learning even without having responded
  they turned right
• Doesnt that mean they have some internal
  representation of the maze?

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Latent Learning (without Reinforcement)

• Tolman and Honzik (1930) over two weeks,
  different groups of rats were placed in a maze,
  as at left.
• Group 1 was reinforced whenever they reached the
  goal Group 2 was never reinforced Group 3 was
  reinforced but only on day 11
• S-R prediction Group 3 should look like Group 2
  till day 12, then show gradual improvement like
  Group 1 but they dont

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Evidence for Cognitive Maps?

• Tolman (1948) should rats used mental
  representations (cognitive maps)
• Rats were introduced into maze and allowed to
  explore it
• S-R theory predicts that association of food with
  paths should be inversely proportionate to their
  length
• If path 1 is blocked at A, path 2 is still open.
• If path 1 is blocked at B, path 2 is also
  blocked.
• But the rats wouldnt know this if they had no
  internal representations of the maze.
• Rats chose path 3 90 of the time when path 1
  blocked at B

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Knowledge of Grammar

• What sets language apart from other
  communication systems Grammar
• Set of rules that allow the communicator to
  combine arbitrary symbols to convey
  meaning
• Three aspects
• Phononlogy Rules for word sounds
• Syntax Rules for combining words to make
  sentences
• Semantics Rules used to communicate meaning
  Rules of syntax determine how words combine into
  phrases, and phrases into sentences
• Chomskys idea of how sentences work
• Surface structure Superficial appearance,
  literal ordering of words
• Deep structure Underlying representation of
  meaning
• Producing sentences requires transformation of
  deep structure into a surface structure

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Transduction, Sensation, Perception

• How does the external environment get into the
  nervous system?
• Transduction Process of translating external
  messages into the internal language of the brain.
• Problem of Transduction how does external energy
  become internal information (neural activity).
• How do sensations get extracted and passed up to
  brain centres?
• How do sense organs (specialized receptor cells)
  and sensory nerves process incoming energy and
  offer information up to higher brain centres?
• Assumption knowledge of world is in large
  measure derived through senses perception is
  mediated by the senses.
• How is our experience of a meaningful world to be
  explained? How does perception happen?
• Perception is the meeting place of world and
  mind.
• Perception is the way the world becomes your world

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Young Woman/Old Woman?
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Necker Cube
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Variations on Necker Cube

• Circles also appear to change plane with inversion

• Necker cube inversion remains possible

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Depth Illusions
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Depth Illusion
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Illusion of Depth
Ponzo Illusions
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The Ames Room
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Is that an X or circles?
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Early Memory Research

• Ebbinghaus in 1885 conducted some of the first
  experimental studies on memory
• E.g. subject required to learn (successfully
  recite) 420 lists of 16 nonsense syllables each
  (chosen since they were assumed to have no prior
  associations)
• Repetition facilitates memory
• Memory declines as a function of time (forgetting
  curve)
• Found savings reduction in trials needed to
  relearn a list
• Discovered serial position effect (items at
  beginning and end of a a list are more readily
  recalled)
• Assumptions memory is a mechanical, passive
  registration of events set isolates memory from
  other cognitive functions (intention,
  interpretation)

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Ebbinghaus Forgetting Curve
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More Early Memory Research

• Bartlett (1932) tried to study memory in a less
  artificial (more realistic) setting, assessing
  subjects memory for folk tales and stories
• Found that many details left out, others inserted
• Memory was a reconstructive process, rahter
  than a reproductive process
• Alternative to mechanistic, S-R approach to
  memory
• Reconstruction is guided by schemata, generalized
  knowledge structures

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Internal vs. Ecological Validity

• An advantage of experiment (as opposed to
  descriptive research and mere observation) is the
  level of control researchers have (manipulation
  of independent variable)
• A disadvantage is that the highly controlled
  setting in a laboratory is unlike the reality of
  everyday life
• Often there is a trade-off between internal and
  ecological validity

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Gestalt Principles Illustrated
Source http//www.cl.cam.ac.uk/Teaching/2000/AGra
phHCI/HCI/hcinotes.html
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Gestalt Principles Stated

• Five laws that govern visual organization
• Proximity Elements that are close to each other
  are seen as being part of the same object
• Similarity Items sharing physical properties are
  put into the same set
• Closure Figures with gaps or small missing parts
  of the border are seen as complete
• Good continuation Lines that are interrupted are
  seen as continuously flowing
• Common fate Things moving in the same direction
  are seen as a group