Abstract
The Pulfrich effect is a stereo-motion phenomenon. When the two eyes are presented with visual targets moving in fronto-parallel motion at different luminance or contrast, a target moving-in-depth is perceived. This percept of motion-in-depth occurs because lower luminance or contrast is thought to delay visual processing. Spatial properties of an image such as spatial frequency and size have also been shown to influence the speed of visual processing. In this study, we used a paradigm, based on the Pulfrich phenomenon, where a structure-from-motion defined cylinder – composed of Gabor elements displayed at different interocular phases – rotates in depth to measure interocular delay. Hence, we measured the relative delay in processing between the eyes while independently manipulating the spatial frequency and size of the Gabor patches. Seven adults with normal vision were tested. We show that interocular differences in spatial frequency of the Gabor patches, but not size, produces processing delays.