RETENTION OF LOCAL INFORMATION IN GENERATION OF SUBJECTIVE CONTOURS

Temporal integration characteristics of subjective contour perception was investigated, using the sequential presentation of two pairs of di sks with a sector removed. In the first experiment, by matching the co ntrast of a ''real'' stimulus, the perceived contrast of the subjectiv e contours was measured as a function of the stimulus onset asynchrony (SOA) between the two pairs of the disks. With increasing SoA, the pe rceived contrast decreased gradually and levelled off at the SoA of ca 372 msec (1 SD = 119 msec), In the second experiment, the perceived c ontrast of the inducing disks was measured as a function of SOA using the matching method. The time limit of the additive effect for the con trast perception of the inducing disks was much shorter than that for subjective contours; the critical SOA was ca 65 msec (1 SD = 36 msec). The remarkable difference of the integration time was explained by a hierarchical process; the local spatial filtering, the retention of lo cal information, and the completion of gaps by multiplicative or AND o peration. (C) 1997 Elsevier Science Ltd.