Sensorimotor adaptation modifies action effects on sensory binding.

Previous studies have shown that performing a motor action toward a target decreases the perceptual asynchrony observed in a temporal order judgment (TOJ) of a change in the target's visual attributes. We examined the temporal limit of this effect and whether this temporal limit can be extended through sensorimotor adaptation. Participants performed a TOJ task related to changes of the position and color of a visual stimulus in a perceptual and a motor task. A fixed change (color or position) occurred 250 or 500 ms following an auditory cue (perceptual task) or the end of a manual reaching action (motor task), whereas the variable change (position or color) occurred randomly within a time window of ±200 ms locked to the fixed change. The points of subjective simultaneity (PSSs) revealed that performing a voluntary action decreased the temporal asynchrony observed in the perceptual task, but only in the 250-ms delay condition. In Experiment 2, the fixed change occurred 1 s after either an auditory cue or the end of a manual reaching action, and the variable change occurred either simultaneously (new sensorimotor contingencies, 60 % of trials) or within a time window of ±200 ms (40 % of trials). The PSSs revealed that temporal asynchrony decreased in the motor task, but only after adaptation to the 1-s delay. Taken together, these data show that voluntary motor action affects the temporal binding of visual attributes for a period of less than 500 ms after the end of the action. Sensorimotor adaptation can nevertheless extend this time interval, at least up to 1 s.