Term
| Absolute movement perception |
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Definition
ability to see a single target move in a featureless (dark) environment.
Threshold = 10 minutes of arc per second |
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Term
| Relative Movement Perception |
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Definition
ability to notice movement when there are other features present
Threshold= 1 minute of arc per second |
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Term
| Upper threshold for real movement perception |
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Definition
if target moves too fast, we see a blur rather than a movement.
15 degrees of arc per second. (pretty slow) |
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Term
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Definition
| often easier to see movements in the periphery of the visual field than it is to see stationary targets. When fixated on target in periphery, it eventually fades and disappears, coming back into view when disrupted by target movement. |
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Term
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Definition
Rule by visual system that implies if there is relative motion between a large surrounding stimulus and a smaller stimulus, it must be the smaller stimulus that is actually moving.
Ex. seeing a stationary dot move because the frame around it is moving |
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Term
| Motion during pursuit eye movements |
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Definition
| when following a moving target with your eye, the moving target is seen as stationary on your retina but the background moves across the retina. but you see the background as stationary and the target as moving. |
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Term
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Definition
| we can perceive motion when nothing is moving on the retina such as watching TV due to stimuli being presented at different times and places on the retina. |
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Term
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Definition
observers cannot see an object moving across the space between two points, only a moving blur is perceived.
(indicates there may be a dissociation between form and motion processing in the visual system) |
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Term
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Definition
| mathematical relationships that describe the effects of stimulus duration, interstimulus intervals and stimulus distance on apparent motion |
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Term
Waterfall phenomenon
(motion aftereffect) |
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Definition
seeing trees move upward, opposite direction of movement of waterfall after a long period of time looking at the waterfall.
Explanation: detectors coding motion in one direction gets fatigued so that detectors in other direction have higher response rate and so signals inappropriately, |
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Term
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Definition
| Illusion of movement when a stationary luminous point is viewed in the dark and highly influenced by suggestion. |
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Term
| theories for autokinetic movement |
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Definition
1) visual stimulus moves on retina due to eye movement and so observer misperceives that the eye motion is stimulus motion. (idea disproved)
2) internal signals to correct eye drift are interpreted as movement of the target |
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Term
| Visual Pathology that effects autokinetic movement |
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Definition
1) hemianopia
- drift is toward the better part of the field
2) muscle palsy
- drift is towards the affected muscle |
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Term
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Definition
| we can immediately perceive some complex motions as representing a person moving despite the lack of contour or other info |
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