Illusory motion capture and release in rotating 3-D figure in humans

An illusory bar emerges in a cleft between two opposing gratings. When the gratings rotated around the vertical axis in three-dimensional (3-D) space, the illusory bar was seen either (i) rotating with the inducing gratings o r(ii) as a stationary and opaque tape located in front of gratings. This il lusion seems to be caused by the different temporal dynamics of the illusio n and its inducers, especially by the slower extinction rate for the illuso ry bar than its inducers. The illusion is a psychophysical demonstration of an illusory figure becoming spatially and temporally loose from its induce rs, suggesting that they are processed separately in the brain. This indica tes that illusory figures are not only by-products of normal vision but hav e their own important function. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.