On the time-course of inhibition in the stereoscopic perception of rows of dots

Perception of depth difference between two dots is more difficult if additional dots intervene between them. By varying the onset asynchrony (SOA) between the endpoints and one or several intervening dots, we measured the time-course of the process that elevates stereoscopic thresholds. It turned out that adding the intervening dots under these conditions decreased performance to, and often below, the level that was achieved with a total presentation time corresponding to the SOA for intervening dots presented both binocularly and monocularly. This is an indication for an active inhibitory process.