Future alters past

We demonstrate a novel visual illusion wherein the appearance of past events is altered by the appearance of future events. Human observers were presented a two-frame apparent motion of a flash; here we changed the size of the flash across frames. We observed that the size of the flash on the first frame was perceptually attracted toward the size of the flash on the second frame. The apparent change in the size of visual flash possibly stems from averaging of flash sizes on the basis of spatiotemporal integration of visual flashes. This sort of understanding of psychophysical mechanism for visual perception can contribute to future information technologies in a novel and user-friendly manner.