Abstract
When an observer is presented with dissimilar images to the right and left eye, the images will alternate every few seconds in a phenomenon known as binocular rivalry. Recent research has suggested that the initial ‘onset’ period of rivalry is not random and may be different in its neural mechanism than subsequent dominance periods. It is known that differences in luminance and contrast have a significant influence on the average dominance during sustained rivalry and that perception of luminance can vary between individuals and across the visual field. We therefore investigated whether perception of luminance contrast plays a role in onset rivalry. Rival targets were matched for brightness in each of eight locations of the near periphery for each observer. Observers then viewed the rival targets for brief presentations in each of the eight locations and reported the color that was first dominant in each location. Results show that minimizing differences in brightness and contrast yields a stronger pattern of onset dominance bias and reveals evidence of monocular dominance. Specifically, a significant advantage was observed for the temporal hemifield, with the left or right eye’s image each significantly more likely to dominate when it was presented in left or right visual field locations respectively. These results suggest that both contrast and monocular dominance play a role in onset dominance, though neither can fully explain the effect. Drawing from additional current research, a brief overview of other factors contributing to dominance at the onset of rivalry will also be presented. Together, these results further clarify the distinction between perceptual dominance at onset and the dominance periods during subsequent alternations.
Meeting abstract presented at VSS 2013