Abstract
Our movements constantly change the way we perceive external stimuli. A prime example is sensory attenuation, a phenomenon that occurs when we actively produce a sensory event. Previoulsy, sensory attenuation has been reported for self-touch but also for the generation of sounds by button presses. In this study, we investigated a novel explanation of sensory attenuation. We assume that a pre-motor attention shift - which usually accompanies goal-directed movements - boosts tactile sensitivity at the location of the body that makes contact with the goal object. Attentional prioritization for the tactile modality during a goal-directed hand movement might lead to a transient reduction in sensitivity in other modalities, resulting in sensory attenuation for sounds. In a first experiment participants were asked to press a virtual button. The virtual reality setup allowed to manipulate the time of tactile feedback during the hand movement phase with either presenting it at the beginning of the movement vs. during movement vs. at the exact moment of button pressing. We found that tactile sensitivity was highest during button press. In a second experiment, participants had to push a virtual button in order to produce a sound. They had to compare its intensity to a second sound that appeared 700 ms later. Participants either received tactile feedback at the time they virtually touched the button or at the time of movement start. We found sensory attenuation for sounds only when tactile feedback was provided at the time the movement goal was reached. Together, these results suggest that a pre-motor tactile attention shift briefly decreases auditory sensitivity. We conclude that sensory attenuation for sounds occurs because tactile attention is boosted when reaching the movement goal, leaving reduced attentional resources for the auditory modality.