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The McCollough effect: dissociating retinal from spatial coordinates
1Department of Psychology, University of Arizona, Tucson 85721.
Perception & Psychophysics
|October 1, 1993
Summary
The McCollough effect, a visual illusion, is not based on real-world object properties. Manipulating stimulus orientation showed the effect relies on retinal, not perceived, orientation cues.
Area of Science:
- Psychology
- Neuroscience
- Visual Perception
Background:
- The McCollough effect demonstrates how prolonged exposure to a color-contingent visual stimulus can induce a color aftereffect.
- Previous research has explored the role of both retinal and perceived orientation in this phenomenon.
Purpose of the Study:
- To investigate whether the McCollough effect is contingent on the retinal orientation or the perceived spatial orientation of a stimulus.
- To dissociate the contributions of retinal and perceived orientation to the McCollough effect.
Main Methods:
- Three experiments were designed to manipulate the relationship between stimulus color, retinal orientation, and perceived orientation.
- Experiment 1: Head tilting was used to decouple retinal from perceived orientation.
- Experiment 2: Spatial contingency was eliminated while retinal contingency was maintained.
Main Results:
- Eliminating the retinal orientation contingency (Experiment 1) resulted in a significantly reduced aftereffect.
- Eliminating the perceived spatial orientation contingency (Experiment 2) did not reduce the aftereffect.
- Further analysis revealed residual effects in Experiment 1 were due to uneliminated retinal contingencies.
Conclusions:
- The McCollough effect is primarily driven by retinal orientation, not perceived spatial orientation.
- The findings suggest the McCollough effect is not directly linked to real-world object properties or spatial awareness.
- This challenges theories that propose the effect reflects learning about environmental regularities.