A sensorimotor account of vision and visual consciousness

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A sensorimotor account of vision and visual
consciousness

• J. Kevin ORegan
• Alva Noë

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Overview

• standard working hypotheses
• sensorimotor contingencies
• visual perception
• visual awareness
• visual consciousness
• bridging the gap

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Standard view

• for every perceptual state there is a neural
  correlate
• neural correlates of consciousness
• bridge locus (perfect correlate, sufficient to
  produce the percept)
• neural substrate produces representations

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Problems?

• even with perfect correlate no explanation for
  how the neural substrate generates the percept
  (explanatory gap)
• ? neural substrate alone not sufficient to
  produce vision (resp. a percept)

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Which neurons correlate best with the percept?

• e.g. motoneurons

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Basics (sensorimotor contingencies)

• structure of the rules governing sensory changes
  produced by various motor actions
• two types of sensorimotor contingencies
• determined by character of visual apparatus
• belonging to visual attributes of objects

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Sensorimotor contingencies

• Figure 1. Top The eye fixates the middle of a
  straight line and then moves to a point above the
  line. The retinal stimulation moves from a great
  arc on the equator of the eye to a different,
  smaller great arc. Bottom left Flattened out
  retina showing great arc corresponding to equator
  (straight line) and off-equator great arc (curved
  line). Triangles symbolize color-sensitive cone
  photoreceptors, discs represent rod
  photoreceptors. Size of photoreceptors increases
  with eccentricity from the center of the retina.
  Bottom right Cortical activation corresponding
  to stimulation by the two lines, showing how
  activation corresponding to a directly fixated
  straight line (large central oblong packet
  tapering off towards its ends) distorts into a
  thinner, banana shaped region, sampled mainly by
  rods, when the eye moves upwards. As explained in
  Section 2.2, if the eye moves along the straight
  line instead of upwards, there would be virtually
  no change at all in the cortical representation.
  This would be true even if the cortical
  representation were completely scrambled. This is
  the idea underlying the theory that shape in the
  world can be sensed by the laws obeyed by
  sensorimotor contingencies.

SHOW
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Visual quality of shape

• set of all potential distortions that the shape
  undergoes when it is moved relative to us, or
  when we move relative to it
• infinite set
• but laws can be extracted which describe the set
• ? set of laws codes shape

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Mastery of the laws

• the sensorimotor contingencies are there
• ? mastery knowing about them
• (dependent on context of behaviour / habitual
  setting)

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Visual Perception

• Vision is a mode of exploration of the world that
  is mediated by knowledge, on the part of the
  perceiver, of what we call sensorimotor
  contingencies.

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Visual awareness

• exploring environment according sens cons
• active exercise of mastery of the laws
• integration of this mastery with
• thought or action-guidance
• seeing
• matter of degree
• but without current access no perception

sens cons sensorimotor contingencies
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Visual Consciousness

• two types
• transitive visual consciousness (visual
  awareness)
• visual consciousness in general (ability to
  become aware)

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Explanatory Gap

• Gap? Which gap?
• there is nothing that fits notion of qualia
• the subject matter of phenomenological
  reflection is not an ephemeral, ineffable,
  sensation-like momentary occurrence in the mind,
  but, rather, the real-world, temporally extended
  activity of exploring the environment and the
  structure of sensorimotor contingencies
• ? argument does not apply

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Important claims

• laws of sensorimotor contingencies constitute the
  way the brain codes visual attributes
• experience as a mode of skillful activity
• world as external memory
• brain as one element in a system

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Major drawbacks

• Has a computer program (e.g. the missile guidance
  system from the paper), that has mastery of the
  sensorimotor contingencies and plans with them,
  consciousness?
• What are the grounded terms? (If you paraphrase a
  circle as a thing that becomes, watched from
  another perspective, an ellipse, what then is an
  ellipse?)

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References

• ORegan J.K., Noë, A. (2001). A sensorimotor
  account of vision and visual consciousness.
  Behavioral and Brain Sciences, 24(5), 939-973.

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