Perceiving Movement

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Perceiving Movement

• Real Movement
• Apparent Movement/StroboscopicMovement
• Induced Movement

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Perceiving Movement

• Apparent Movement/Stroboscopic Movement

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Perceiving Movement

• Induced MovementImagine sitting in a train and
  the there is a train next to yours. When the
  other train moves, at first it might feel that
  your train is moving backwards.
• Relative motion produces the illusion of movement
  in the stationary object. This is referred to as
  vection.

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Perceiving Movement

• Movement Afterimage

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Perceiving Movement

• Neural Feature DetectorsBars at different
  angles were shown to cats. Some cells responded
  selectively to the orientation of the bars

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Perceiving Movement

• Neural Feature DetectorsThis network responds
  to movement from right to left but not left to
  right

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Perceiving Movement

• Neural Feature Detectors

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Perceiving Movement

• Neural Feature Detectors

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Perceiving Movement

• Neural Feature DetectorsWhen monkeys were
  trained to detect movement, neurons in the Medial
  Temporal Dorsal stream fired at a higher rate
  when the dot movement was correlated

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Perceiving Movement

• Corollary Discharge Theory Motor Signals (MS)
  to move the eyes, including a Corollary Discharge
  Signal (CDS) and and Image Movement Signal (IMS)
  are processed by the Comparator. The IMS and the
  MS balance each other out.

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Perceiving Movement

• Corollary Discharge Theory Motor Signals (MS)
  to move the eyes, including a Corollary Discharge
  Signal (CDS) and an Image Movement Signal (IMS)
  are processed by a Comparator
• Perception of movement w/o movement in the retina
  1. Move eyes while viewing an afterimage in the
  dark. You have a MS and CDS but no IMS.
  Afterimage moves with the retina2. Push on your
  eyeball while looking at a stationary location.
  You get CDS w/o IMS. Scene moves.3. Follow a
  moving object with eyes. You get CDS w/o IMS.
  Object appears to be moving.4. Paralyze your eye
  muscles and then try to move your eyes. You
  get CDS w/o IMS. The scene moves.

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Perceiving Movement

• Corollary Discharge Theory This study of
  monkeys showed that certain neurons only respond
  to the IMS and take eye movement into account.

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Perceiving Movement

• The Optic Array
• 1) Foreground object moves against a stationary
  background
• 2) The entire scene moves, indicating the
  observer is moving

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Perceptual Organization andMovement
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Perceptual Organization Movement

• Biological Motion

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Perceptual Organization Movement

• Biological Motion

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Perceptual Organization Movement

• Structure from motion the kinetic depth effect

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Perceptual Organization Movement

• Motion capture items forming groups move together

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Perceptual Organization Movement

• Constraints on movement