Kinetic Aftereffect Illusion


KINETIC DEPTH EFFECT. The Germanborn American perceptual psychologist Hans Wallach (1904-1998) described the kinetic depth effect in which a moving two-dimensional shadow that is cast by a three-dimensional object (e.g., a rod) appears to be three-dimensional when the object is positioned obliquely and rotated about its center. This causes complex transformations making the shadow appear to move in the front of, and behind, the surface on which it is cast. If the object stops moving (or if it rotates in a plane that is perpendicular to the surface on which the shadow is cast - causing the shadow to shorten and lengthen as the object rotates), then the kinetic effect disappears. This effect is related closely to the visual windmill illusion -first noted by the English mathematician Robert Smith (1689-1768) - in which the blades of a windmill (seen from a distance and silhouetted against the sky) appear to reverse their direction of rotation. See also ALIAS-ING/STROBOSCOPIC PHENOMENON; APPENDIX A; PERCEPTION (I. GENERAL), THEORIES OF; PERCEPTION (II. COMPARATIVE APPRAISAL), THEORIES OF.

Conquering Fear In The 21th Century

Conquering Fear In The 21th Century

The Ultimate Guide To Overcoming Fear And Getting Breakthroughs. Fear is without doubt among the strongest and most influential emotional responses we have, and it may act as both a protective and destructive force depending upon the situation.

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