Effects Of Saccade On Audiovisual Cross-modal Simultaneity Judgments

The cross-modal integration of audiovisual sensory information plays a very important role in our daily life.This integration can improve the speed and efficiency of information processing in the brain and promote our perception of life events as a whole.But not any audio-visual information will be integrated.It is very important for cross-modal integration that audiovisual stimuli present synchronously.Previous studies on audiovisual simultaneity judgments mostly focus on fixation condition.However,we need to saccade constantly to get interested information.The latency of nervous system response to visual stimuli is shortened in the saccade condition,which lead to our perception of the onset time of visual stimuli being advanced,resulting in temporal perception distortion such as time compression and timing inversion.Saccade is not affected the temporal perception of auditory stimuli.In this study,two experiments are conducted to explore whether saccade modulate cross-channel simultaneity judgment.Saccade can advance our perception of the onset time of visual stimuli,but does not affect the temporal perceptual of auditory stimuli.Our audiovisual cross-modal simultaneity judgments may be recalibrated,when audiovisual stimuli are presented simultaneously at the beginning of saccade.In experiment 1,audiovisual temporal judgment(TOJ)task was used to explore the modulation of saccade on audiovisual cross-modal simultaneity judgment.We set up saccade and fixation conditions.The experimental results showed that saccade advanced our perception of the onset time of visual stimuli.When the audiovisual presented simultaneously at the beginning of saccade,the subjects were more inclined to judge that the visual stimuli presented first.There was no such phenomenon in the fixation condition.In experiment 1,we found that saccade advanced our perception of the onset time of visual stimuli,but the cause of this phenomenon was unclear.Saccade amplitude can modulate the effect size of chronostasis,so saccade amplitude may also modulate the effect size of experiment 1.In experiment 2,we set up 200 and 400 saccade amplitude conditions.The experimental results also showed that saccade advanced our perception of the onset time of visual stimuli,but the effect size was not modulated by saccade amplitude.