Chapter 8: Perceiving Motion Flashcards

1
Q

What are the 3 functions of movement perception?

A
  1. Understanding events: movement of objects assist in organization of stimuli
  2. Attracting attention: important for survival if predator
  3. Information about objects: ambiguous objects could be misinterpreted without movement of objects or observer
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2
Q

What is Akinetopsia?

A

Motion agnosia; damage to cortex resulting in an inability to perceive movement

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3
Q

What is Attentional Capture?

A

Motion attracts attention to the moving object

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4
Q

What are 4 ways to perceive motion?

A
  1. Real motion
  2. Illusionary motion: basis of movement in movies
    - ex, apparent motion
  3. Induced motion: movement of one object causes perceived movement of another
    - ex, moon moving behind the clouds
  4. Motion Aftereffect: looking at a moving stimulus 30-60secs then stationary object looked at will be perceived to be moving in opposite direction
    - ex, waterfall
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5
Q

Explain Larson’s experiment involving real vs apparent motion

A

3 conditions:

  1. Control condition: 2 dots flashing simultaneously
  2. Real motion: 1 dot moving
  3. Apparent motion: 2 dots flashed to appear as if moving
    - Result: (1) activated separate areas of visual cortex
    - Result: (2) and (3) activated similar areas
    - Finding: perception of motion is related to the same brain mechanisms
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6
Q

What are the 3 conditions of motion perception?

A
  1. Object moves, observer is stationary: creates moving image on retina
  2. Object moves, observer’s eyes follow: stationary image on the retina
  3. Observer moves through stationary environment: moving image on retina but environment is perceived as stationary
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7
Q

What are the 2 explanations for motion perception?

A
  1. Ecological approach: info is available in the environment for perception
  2. Physiological approach: neural processing
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8
Q

Define Local Disturbances

A

Disruptions in the optic array by covering/uncovering the background in part

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9
Q

Define Global Optic Flow

A

Overall movement of optic array indicating that an observer is moving, not the environment

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10
Q

What is the Reichardt Detector?

A

A neural network that encodes motion

When receptors are stimulated right to left, neuron fires

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11
Q

Explain the Corollary Discharge Theory

A

Movement perception depends on 3 things:

  1. Motor signal (MS): signal sent to move eye muscles
  2. Corollary discharge signal (CDS): split of an MS
  3. Image displacement signal (IDS): movement of image stimulating receptors across the retina
  • Movement is perceived when Comparator receives input from either CDS or IDS BUT NOT BOTH
    (Explains why environment perceived as stationary when observer moves through stationary environment)
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12
Q

What are 2 pieces of evidence that support the corollary discharge theory?

A
  • Damage to MST leads to perception of movement of stationary environment
  • Patient R.W.: damaged MST, IDS was created by eye movements
  • Real-Movement Neurons: in monkeys, respond only when a stimulus moves and not when eyes move
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