Abstract
Repeated exposure to apparent motion in one direction may cause the observer to perceive a subsequently presented stationary/moving stimulus as moving in the opposite direction (Mather et al 1998; Konkle et al 2009). Here we demonstrate that aftereffect of adaptation take place not only in the spatial dimension but also in the temporal dimension. We employed a visual Ternus display and randomly varied the inter-stimulus-interval (ISI) between the two frames (from 50 to 200 ms) in the display to determine the transition threshold between “group motion” and “element motion”. In Experiment 1, participants saw 7∼9 presentations of Ternus display with an ISI of either 50 ms (for element motion) or 200 ms (for group motion) followed by a probe Ternus display with an ISI equivalent to the transition threshold. In Experiment 2, participants heard 7∼9 presentations of paired beeps with an ISI of either 50 or 200 ms and saw the same probe as in Experiment 1. Adaptation to the visual or auditory stimuli with short ISI led to more reports of “group motion” for the probe while adaptation to stimuli with long ISI had no effect. This temporal adaptation contrasts with the usual bi-directional effects for spatial adaptation.