Binocular integration in line rivalry

Abstract

Three experiments investigated the frequency of a monocular, partial binocular, or nearly total binocular report of dichoptically presented stimuli in a line rivalry paradigm. The consistently important variable was the duration of the presentation time of the stimuli, which ranged from 50 to 1,100 msec, with each experiment covering only a portion of these times. Variations in equipment, instructions, response mode, light intensity, and position in the visual field were introduced. The main result was a report of fusion of the binocular inputs, with little or no suppression for about 40% to about 80% of the foveal presentations of 100 msec or less, the percentage varying over the three experiments. Partial fusion (some, but not all, lines crossed) was indicated in another 40% or more of the reports. Lateral positioning of the stimuli 6 deg from the fixation point, but not at 3 deg or less, resulted mainly in reports of monocular inputs. The possibility, and serious implication for studies of rivalry phenomena, of range effects (Poulton) from the within-subjects variation of duration of stimuli was noted.