Moving Heads, Moving Sounds: Systematic Errors in Auditory Motion Perception

Abstract

The movement of moving objects seen during self-motion is incorrectly perceived as a result of errors in parsing the visual motion arising from the retina and from information about the movement of the head and eyes in space1. The perception of motion of auditory targets may be even more challenging as previous research suggests that the auditory system lacks dedicated low-level speed processing mechanisms. This study investigates how the perception of a moving auditory sound source is influenced by concurrent head movements, drawing comparisons with established visual motion perception findings and illusions, such as the Filehne Illusion. Participants were asked to move their heads at a fixed speed, either horizontally (left to right or right to left) or vertically (up to down or down to up), while indicating the perceived direction of a moving sound source by using a joystick. A physical sound source was moved silently at a constant speed in fronto-parallel 2D space using a 3x3x3m cable robot. Results showed that head movements created a perceptual bias of the perceived direction of the moving sound source in the opposite direction to the head movement. Responses were less precise during horizontal than vertical head movement, whereas overall directional accuracy did not differ reliably between movement planes. The magnitude of the directional error also depended on the direction of head movement, consistent with the different cues available for horizontal and vertical localization (binaural vs. spectral cues). These findings suggest that similarly to how visual motion perception is distorted by extraretinal signals and the movement of the eyes, so too is auditory motion perception influenced by movement of the ears, revealing errors in the integration of proprioceptive, vestibular and auditory cues that distort the perceived direction of a moving sound source.