In the illusion , a small pink object can be seen moving back and forth in front of three types of background. When observers track the pink target moving back and forth in front of a background consisting of dynamic noise, they report the percept of a drifting background. The direction of this drift is opposite to that of the small pink object, even though the background in fact does not move into a particular direction. This illusory motion arises for a static gray Gaussian background, but is actually much stronger when the background is dynamic random noise. However, the illusion does not occur when the background consists of static random noise.Drifting Background Illusion,
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(© 2007 Masaharu Kato)