It has been hypothesized that the human visual system can use temporal synchrony for the perceptual grouping of image regions into unified objects, as proposed in some neural models. We argue however, that previous psychophysical evidence for this hypothesis is due to stimulus artifacts, and that earlier studies do not, therefore, support the claims of synchrony sensitive grouping mechanisms or processes.

QuickTime movie from our Science, 1999 paper:

movie - the basic stimulus (left) and the results of temporal bandpass filtering (right)

QuickTime movies from our Nature Neuroscience, 2001 paper:

movie - the basic stimulus contains both the integrated contrast and synchrony cue (a central rectangular target region should be visible)

movie - a simple variant of the basic stimulus with the same synchrony cue but no contrast cue; in the absence of the contrast cue, the rectangular target is no longer visible.

movie - another variant of the basic stimulus with the same synchrony cue but no contrast cue