DISPARITY TUNING OF THE STEREOSCOPIC (CYCLOPEAN) MOTION AFTEREFFECT

Across five experiments this study investigated the disparity tuning o f the stereoscopic motion aftereffect (adaptation from moving retinal disparity). Adapting and test stimuli were moving and stationary stere oscopic grating patterns, respectively, created from dynamic random-do t stereograms. Observers adapted to moving stereoscopic grating patter ns presented with a given disparity and viewed stationary test pattern s presented with the same or differing disparity to examine whether th e motion aftereffect is disparity contingent. Across experiments after effect duration was greatest when adapting motion and test pattern bot h were presented with zero disparity and in the plane of fixation. Aft ereffect declined as disparity of adapting motion and/or test pattern increased away from fixation, even under conditions in which depth pos ition of adapt and test was equal. This argues against a relative dept h separation explanation of the decline, and instead suggests that the amount of adaptable substrate decreases away from fixation.