Monocular occlusion cues alter the influence of terminator motion in the barber pole phenomenon.

The influence of monocular occlusion cues on the perceived direction of motion of barber pole patterns is examined. Unlike previous studies that have emphasized the importance of binocular disparity, we find that monocular cues strongly influence the perceived motion direction and can even override binocular depth cues. The difference in motion bias for occluders with and without disparity cues is relatively small. Additionally, although 'T-junctions' aligned with occluders are particularly important, they are not strictly necessary for creating a change in motion perception. Finally, the amount of motion bias differs for several stimulus configurations, suggesting that the extrinsic/intrinsic classification of terminators is not all-or-none.