THE SPATIOTEMPORAL PROPERTIES OF THE CRAIK-O’BRIEN-CORNSWEET EFFECT ARE CONSISTENT WITH "FILLING-IN"

M. P. Davey, T. Maddess and M. V. Srinivasan

The Craik-O’Brien-Cornsweet Effect (COCE) is an illusion in which luminance discontinuities give rise to illusory brightness. One hypothesised mechanism for the induction of illusory brightness is that the cortex constructs a brightness percept from edge information by a lateral "filling-in" process. A requirement for the filling-in hypothesis is that ability of the illusion to form would be limited by the speed of propagation of the filling-in. The results presented here from 3 methods indicate that in the case of COCE gratings brightness information propagates at a fixed speed across the central visual field of about 19 deg/s, and across visual areas V1 or V2 at 155 or 205 (±20) mm/s respectively.