PERCEPTUAL GROUPING IN-SPACE AND TIME - EVIDENCE FROM THE TERNUS DISPLAY

We report three experiments investigating the effect of perceptual gro uping on the appearance of a bistable apparent-motion (Ternus) display . Subjects viewed a Ternus display embedded in an array of context ele ments that could potentially group with the Ternus elements. In contra st to several previous findings, we found that grouping influenced app arent motion perception. In Experiment 1, apparent motion perception w as significantly affected via grouping by shape similarity, even when the visible persistence of the elements was controlled. In Experiment 2, elements perceived as moving without context were perceived as stat ionary when grouped with stationary context elements. In Experiment 3, elements perceived as stationary without context were perceived as mo ving when grouped with moving context elements. We argue that grouping in the spatial and temporal domains interact to yield perceptual expe rience of apparent-motion displays.