Numerous studies indicate that the visual system ultimately represents partly occluded objects as completed forms, and that interpolated contours and surfaces play a great role in these situations. We explore how visual interpolation process depends on spatial and temporal stimulus attribute: movement of occluder. In order to overcome spatially and temporally fragmentary inputs, we hypothesized that visual interpolation process could encode the briefly-viewed fragments in a buffer and integrate them with later-appearing fragments. Kellaman, Guttman and Wickens (2001) called this "the persistence hypothesis".

We examined the temporal limits of visual persistence with shape discrimination task used in previous studies (Unuma, Hasegawa, & Kellman, 2006; Ringach & Shapley, 1996). Specifically, we conjectured that if fragmentary elements are integrated and produce a shape, the performance of shape discrimination task should be better than those with fragmental elements. Illusory-contour squares and large occluder with small window were presented to observers. The occluder rotated on the illusory square and the speed of rotary motion was manipulated. The method of constant stimuli was used. The psychometric functions for the discrimination of the shape was measured as a function of presentation cycle of inducing figures.

Results showed that with increasing presentation cycle, percentage of correct response increased. These results support the notion that visual edges can be encoded in a temporally limited buffer, and that interpolation process can integrate spatially and temporally fragmentary elements behind moving occluder.