Abstract
Binocular rivalry occurs when two dissimilar images are dichoptically presented, each to a different eye. Neighboring image-parts with similar features, such as motion or orientation, tend to be perceived together for longer durations than image-parts with dissimilar features, i.e. grouping occurs. Previous studies have shown that this grouping depends on a shared eye-of-origin to a much larger extent than on image content, irrespective of the complexity of a static image. Here, we address the question whether grouping of optic flow patterns is also primarily driven by monocular information. In addition, we examine whether parameters, such as optic flow direction, and partial versus full visibility of the optic flow structure, affects grouping durations during rivalry. For each eye, two apertures (diameter 1.0°) were presented above and below the fixation dot (diameter ~0.22°). Each aperture contained either optic flow (expansion or contraction) or incoherent motion. The speed of the dots of the optic flow pattern increased from center (0.086°/s) to periphery (1.49°/s). The dots were colored either white or black and observers had to track the color of the dots they perceived in the two apertures during 1 minute trials. The results show that, as for static images, grouping of motion information is primarily affected by its eye-of-origin. The motion direction of the optic flow pattern (i.e. the ‘image cue’) only affected grouping durations when full optic flow patterns were presented within each aperture. This effect was absent for partial optic flow parts that could be perceived holistically as a single optic flow pattern. These results suggest that grouping during rivalry is primarily driven by monocular information even for complex motion stimuli thought to rely on higher-level motion areas.
Meeting abstract presented at VSS 2015