Saccadic Eye Movement Cause Alternation In Awareness During Binocular Rivalry:an Eye-tracking Study

When the left and the right eye are presented with different images, both of the percept can be seen alternately. This phenomenon is called binocular rivalry. Some Relevant studies have shown that there is a positive correlation between saccade and percept alternation. They also find that saccade is not essential to initiate percept changes the fovea image change resulting from a saccade is a deciding factor for percept dominance. And some researchers indicate, rivalry is modulated by extra-retinal eye movement signals elicited by saccade, because of the increase of percept alternation when retinal image position changed, which is more effective than saccade. But the researchers did not proved this preference or guessing that extra-retinal eye movement could influence perception flips by an experiment to give a forceful evidence.Therefore, this paper studies the role of saccade and extra-retinal eye movement playing in binocular rivalry with Gaze-Contingent technology and eye tracking method.This paper include two experiments:In experiment1, subjects are asked to observe the rivalry pictures and report their percept changes synchronously in two kind of display modes-gaze-contingent mode and still pictures mode (regular mode). We assume that if gaze-contingent mode can really control the position of retinal image, the mean durations of dominant percept in rivalry in the two modes should be different. According to the previous studies, the alternation rate of percept will decrease when the position of retinal image has been controlled.In experiment2, subjects are asked to observe the rivalry pictures and report their percept changes synchronously in two kind of display modes. Different with experiment1, subjects should also make a saccade when they heard a warning tone. We assume that if there is a positive correlation between the saccade and percept alternations, it is reasonable to conclude the effect is resulted from extra-retinal eye movement. We also compare the difference of relations of saccade and percept flips between gaze-contingent mode and regular mode to research the interaction effect of influence on binocular rivalry caused by extra-retinal eye movement and retinal image shift.The experiment result shows that the mean duration of percept dominance is longer in gaze-contingent mode. And there is a significant positive correlation between saccade and percept alternations, which disappears when presented with regular mode. We conclude that, the change of retinal image has been controlled in gaze-contingent mode for the rate of percept flips becoming slowly. Even so, saccade still can lead to percept switch during binocular rivalry. Saccade has different effect on percept alternation in rivalry in the two modes. Contrary to the previous studies, there is no relation between saccade and percept alternations. These results support that the extra-retinal eye movement elicited by saccade without retinal image shift can change percept during rivalry. And it indicates that the effect on binocular rivalry from saccade become attenuated if extra-retinal eye movement and retinal image shift function together. This paper apply a new technology to present rivalry stimulates, which may bring some new ideas in the studies of the relationship between saccade and binocular rivalry. And we also offer a direct evidence that extra-retinal eye movement can influence percept alternation in binocular rivalry.