The Role of Experience

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The Role of Experience

• Perceptual Development
• Effects of Learning and Cognition
• Development Vs Hardwiring

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Perceptual Development
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The Measurement of Infant Perception

• A reliable tendency to stare at new stimuli
• Comfort responses and preferences for familiar
  stimuli
• Reliable surprise reactions when configurations
  are altered

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The Development of Visual Acuity

• Vary spatial frequency and contrast compared to a
  gray swatch
• The highest frequency and smallest contrast that
  produce a response determine the acuity of infant
  perception

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The Development of Visual Acuity
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The Development of Visual Acuity
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Stereopsis Use it or lose it

• At Birth, the nerve fibers at the edge of column
  boundaries are poised to cross over and make
  connections with columns from the opposite eye
  that have similar receptive fields

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Stereopsis Use it or lose it

• With normal development, corresponding inputs
  from different eyes cause nerves to overlap
• As with phase detectors, different eccentricities
  are detected in slightly different regions of
  cortex. Such regions then discern different
  disparities.

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Stereopsis Use it or lose it

• If the inputs do not correspond (e.g. child may
  be cross-eyed or have a wandering eye), the
  inputs do not overlap and stereopsis does not
  develop.

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Object Constancy

• By 2 months of age, most children can detect that
  an object is missing

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The Time Course of Perceptual Development
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The Development of Myopia (childhood into
adulthood)

• With excessive up-close viewing, the strain on
  the lens and cilia eventually cause the eyeball
  to shorten to accmodate more easilly
• The Air Force Academy
• Eskimos
• Chicks
• This process can be prevented and reversed by
  using reading glasses and engaging in distance
  viewing (e.g., lots of outdoor activity)

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COGNITIVE ASPECTS OF PERCEPTION
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Top-Down Aspects of Perception

• 1 Categorization
• Attention
• Identification Recognition
• 4 Competition Between Top-Down Bottom-Up
  Information
• 5 Resolving Ambiguity
• 6 Context
• Imagery
• Perception Action
• Perception is Malleable
• Is Perception Modal?
• Concepts

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1 Categorization

• Memory
• Grouping like objects - category exemplars
• Generalization

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2 Attention

• Behavioral and Physiological phenomenon
• Acquisition of Sense Data Cognitive gating of
  sensory/perceptual input -- Guides Acquisition of
  Sense Data
• Competition between Top-Down Bottom-Up
  information

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Cognitive Gating
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Cognitive Gating
There are benefits to keeping your mind on what
youre doing
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The Physiology of Attention

• Amplification (the Pulvinar of the Thalamus)
• De-amplification

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3 Identification Recognition

• Perceptual systems learn to recognize
• Identification for previously seen items is
  faster and more reliable, regardless of whether
  or not you consciously remember

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Disorders of Identification or Recognition

• V3 Visual agnosia
• IT Associative agnosia
• Fusiform gyrus of IT Prosopagnosia

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4 Process Competition

• Irrelevant Information
• Facilitation and Interference
• Stroop Interference

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Stroop Interference
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5 Resolving Ambiguity

• Purpose of perception is unambiguous information
• Gibson- perception is a behavior which actively
  resolves ambiguity
• Perception can be viewed as a probability funnel

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6 Context and Perception

• Context can serve to constrain or resolve
  ambiguity - source of additional information
  (associative) and clues.

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7 Imagery

• What color is your neighbors house?
• Perception in the absence of the stimuli - an
  aspect of memory
• I Mental Rotations
• II Activation of Perceptual Areas
• III Damage to Perceptual Areas Disrupts Imagery
  and Memory

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Mental Rotation

• Reaction Time (RT) Study
• 1 Shepard Mental Rotation - Internalized
  Perception

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Mental Rotation (cont.)

• Straight slope line indicates mental rotations of
  600/sec
• If it werent a rotation, the slope would be
  either flat or irregular

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Mental Rotation (cont.)

• The fact that the result is a straight line
  indicates that the subjects must be rotating
  through the intermediate positions.
• Analog Process - Analogous to Physical Rotations
  mental rotation is constrained in the same way
  that our physical interaction with the
  environment in constrained
• The further apart the objects are, the longer it
  takes to mentally rotate them.

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Mental Rotation (cont.)

• Can blind people do mental rotation? (i.e. Is
  vision necessary for mental rotation?)
• 2 Marmor Zaback - 2-D mental rotation in the
  Picture Plane
• Subjects
• Sighted Blindfolded
• Congenitally Blind
• Blind (Late Blindness have a visual frame of
  reference)

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Mental Rotation (cont.)

• Stimulus
• The figures used here are simpler than those used
  by Shepard.
• Wooden objects fastened to a larger, flat piece
  of wood.
• Present one object to the Left Hand.
• Present another (possibly different) object in a
  different orientation to the Right Hand.

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Mental Rotation (cont.)
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Mental Rotations (cont.)

• Because all of the lines are straight subjects
  are constrained to the physical/mental rotation
  through intermediate positions.
• Vision is NOT necessary to do rotation vision
  just makes for faster mental rotations.

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8 Perception Action

• Recall Gibsons theory that perception is a
  behavior
• As such, part of action must be to help constrain
  perception (e.g., exploration) or inform
  (foraging)
• Similarly, action is directed and updated by
  perception

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9 Perception is Malleable

• Prism Effects on reaching
• Facilitation
• Perception is influenced by expectation

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10 Is Perception Modal?

• Do the senses influence one another?
• Synesthesia
• Barn Owl Optic Tectum (Colliculus)

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11 Concepts

• Pigeons can learn complicated concepts
• From some points of view, concepts are no more
  than configurations of perceptual information
• Or, at least, conceptual processes evolved for
  the purpose of making the best use of perceptual
  information
• What you perceive depends upon what you know

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Do Concepts Help Us Figure Out What Were
Looking At?
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Innate Vs. Developed Nature Vs. NurtureTwo
Species on Their Day of Birth
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Is Perception Innate? Nature vs. Nurture
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Turn That Frown Upside-Down
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Facets of Perception That Are Hardwired

• Bottom-Up Processes
• Neural Organization
• Reflex Mechanisms
• The Reflex Arc
• Visual and Auditory Orientation Reflex
• Range of Perception
• Capacities of Perception
• Attention?
• The Ability to Learn Perceptually and Conceptually

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Facets of Perception That Are Hardwired

• Bottom-Up Processes?
• Neural Organization?
• Reflex Mechanisms
• The Reflex Arc
• Visual and Auditory Orientation Reflex
• Range of Perception
• Capacities of Perception ?
• Attention?
• The Ability to Learn Perceptually and
  Conceptually?

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Facets of Perception That Require Development

• Top-Down Processes
• Attention
• Learning
• Fine-Tuned Functioning
• Acuity
• Stereopsis
• Perceptual Facilitation (Priming)
• Generalization vs. Discrimination

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Conclusion

• Evolution favors what?
• Speed versus flexibility trade-off
• It favors both, but under different
  circumstances.  In rapidly changing environments,
  or in species that occupy varied habitats (like
  humans  everything from the equator to near the
  poles, including jungle, desert, plains, citys,
  farm, etc.) then flexibility is favored.  In
  species where the lifespan is short and/or
  mortality rate is high, speed is favored.