Short-term Perceptual Stabilization in a Bistable Visual Illusion N Kloosterman, T Donner |
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Psychology Department, University of Amsterdam, Netherlands
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| During bistable perceptual illusions, perception alternates spontaneously in the face of constant input. For example, during motion-induced blindness (MIB), a salient target continues to disappear and re-appear for variable durations, when surrounded by a moving pattern. The mode of the distribution of percept durations (i.e., the most frequent MIB duration) is typically longer than 1 s and varies strongly across individuals. Why are only few percepts shorter than the mode? Here, we arbitrated between two scenarios: (i) Observers perceive rapid perceptual alternations but are too slow to report them; (ii) observers do not perceive rapid alternations, due to a mechanism that stabilizes the new percept for some time. Ten observers reported their perceptual alternations during MIB and a rapid alternation between physical target off- and onsets, which was a “replay” of MIB alternations reported by the observer with the shortest mode (“fast replay”). If the first scenario (mode of distribution limited by report) were true, observers should produce the same distributions during MIB and fast replay. In contrast, all observers were equally accurate in tracking the rapid stimulus alternations, thus producing distributions with much shorter modes than during MIB. We conclude that a stabilizing mechanism prevents short percepts during MIB. |
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