Action sounds recalibrate perceived tactile distance

Abstract

Almost every bodily movement, from the most complex to the most mundane, such as walking, can generate impact sounds that contain spatial information of high temporal resolution. Despite the conclusive evidence about the role that the integration of vision, touch and proprioception plays in updating body-representations, hardly any study has looked at the contribution of audition. We show that the representation of a key property of one’s body, like its length, is affected by the sound of one’s actions. Participants tapped on a surface while progressively extending their right arm sideways, and in synchrony with each tap participants listened to a tapping sound. In the critical condition, the sound originated at double the distance at which participants actually tapped. After exposure to this condition, tactile distances on the test right arm, as compared to distances on the reference left arm, felt bigger than those before the exposure. No evidence of changes in tactile distance reports was found at the quadruple tapping sound distance or the asynchronous auditory feedback conditions. Our results suggest that tactile perception is referenced to an implicit body-representation which is informed by auditory feedback. This is the first evidence of the contribution of self-produced sounds to body-representation, addressing the auditory-dependent plasticity of body-representation and its spatial boundaries.