How voluntary movements affect cross-modal temporal perception

We investigated the effect of voluntary movements on cross-modal simultaneous perception using auditory-tactile Temporal Order Judgment (TOJ) task in which participants judged which stimuli had been presented first. In experiment 1, we examined which voluntary movement or proprioceptive information affected TOJ. In experiment 2, we examined the effects of the duration of the voluntary movement and the prediction of the timing of stimuli presentation. When the prediction was available, not the proprioceptive information but the voluntary movements enhanced the temporal resolution of TOJ. According to the increasing of the duration, the point of subjective simultaneity shifted from auditory-first presentation to tactile-first presentation. This result could be attributed to decreasing of attention to the tactile sensation by voluntary movement.