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.