Auditory biological motion processing: the eyes alone don't have it!

Abstract

As social beings, humans need to both perceive and interpret the actions of those around Indeed,the human visual system has been shown to be very sensitive to human movements (so-called biological motion). However, it is often the case, that the movement of other people is not exclusively a visual event. Auditory information often serves as an additional or sometimes the only indicator of biological motion. It is surprising then that auditory biological motion sensitivity has received little attention. The aim of the experiments reported here was to conduct preliminary investigations into auditory sensitivity to biological motion. An initial 'proof of concept' demonstration established that a variety of actions can reliably be identified purely on the basis of sounds resulting from a moving actor's foot strikes. On that basis, a series of experiments investigated auditory sensitivity to the more subtle cues of actor gender and identity. Results of our first experiment indicate an audition-based sensitivity to gender that is at least comparable to the visual equivalent. Similarly, results of our second experiment suggest auditory sensitivity to identity cues. Taken together these findings suggest a remarkable, and heretofore relatively unexplored, level of auditory sensitivity to complex biological motion cues.