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PubMed · 9274752

Moving cast shadows induce apparent motion in depth.

D Kersten·P Mamassian·D C Knill
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Abstract

Phenomenally strong visual illusions are described in which the motion of an object's cast shadow determines the perceived 3-D trajectory of the object. Simply adjusting the motion of a shadow is sufficient to induce dramatically different apparent trajectories of the object casting the shadow. Psychophysical results obtained with the use of 3-D graphics are reported which show that: (i) the information provided by the motion of an object's shadow overrides other strong sources of information and perceptual biases, such as the assumption of constant object size and a general viewpoint; (ii) the natural constraint of shadow darkness plays a role in the interpretation of a moving image patch as a shadow, but under some conditions even unnatural light shadows can induce apparent motion in depth of an object; (iii) when shadow motion is caused by a moving light source, the visual system incorrectly interprets the shadow motion as consistent with a moving object, rather than a moving light source. The results support the hypothesis that the human visual system incorporates a stationary light-source constraint in the perceptual processing of spatial layout of scenes.

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Depth PerceptionHumansLightingMotion PerceptionOptical IllusionsJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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BibTeXRIS

D Kersten, P Mamassian, D C Knill. 1997. Moving cast shadows induce apparent motion in depth.. https://doi.org/10.1068/p260171

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