THE SPATIOTEMPORAL PROPERTIES OF THE CRAIK-OBRIEN-CORNSWEET EFFECT ARE CONSISTENT WITH FILLING-IN

The Craik-O'Brien-Cornsweet effect (COCE) is an illusion in which lumi nance discontinuities give rise to illusory brightness. One hypothesis ed mechanism for the induction of illusory brightness is that the cort ex constructs a brightness percept from edge information by a lateral 'filling-in' process. A requirement for the filling-in hypothesis is t hat ability of the illusion to form would be limited by the speed of p ropagation of the filling-in. The results.presented here from three me thods indicate that in the case of COCE gratings brightness informatio n propagates at a fixed speed across the central visual field of about 19 degrees/s, and across visual areas V1 or V2 at 155 or 205 (+/- 20) mm/s, respectively. (C) 1998 Elsevier Science Ltd. All rights reserve d.