LAUSR

Temporal differences in visual information processing between the eyes can cause dramatic misperceptions of motion and depth. A simple processing delay between the eyes causes a target, oscillating in the frontal plane, to be misperceived as moving along a near-elliptical motion trajectory in depth. Here, we explain a previously reported but poorly understood variant in which the illusory near-elliptical motion trajectory appears to be rotated left- or right-side back in depth, rather than aligned with the true direction of motion. We hypothesized that this variant is caused by differences in the temporal integration periods (i.e. differences in temporal blurring) between the eyes. Differences in temporal blurring dampen the amplitude of motion in one eye relative to the other, and-in a dynamic analog of the 'geometric' effect (Ogle, 1950)-cause the apparent misalignment. A target-tracking experiment shows that temporal blurring is depends on stimulus spatial frequency. A psychophysical experiment shows that when different spatial frequencies are presented to each eye, the direction of perceived rotation is predicted by the eye with the frequency associated with more temporal blur, as assessed by the target tracking task. The current findings add to add to the body of knowledge regarding the dependence of temporal processing on stimulus properties, while highlighting the perceptual consequences of interocular imbalances in temporal processing.