Compression of perceived auditory space during forward self-motion

Humans can perceive a stable auditory environment and appropriately react to a sound source, even when they are moving. This suggests that the inputs are reinterpreted in the brain, while being integrated with information on the movements. Although several studies have shown the influence of the vestibular semicircular canal signals on auditory localization, it is not clear how auditory space representation is modulated by linear accelerations which are obtained from the macular receptors of the otolith system (utricle and saccule). We investigated the effect of the linear acceleration on auditory space representation. During the forward/backward self-motion, a short noise burst was presented from one of the loudspeakers which were aligned parallel to the motion direction when the listener's coronal plane reached the location of one of the speakers (null point). The results showed that the sound position aligned with the subjective coronal plane was displaced ahead of the null point only during forward self-motion. Moreover, all the sounds that were actually located in the traveling direction were perceived as being biased towards the null point. These results suggest a distortion of perceived auditory space in the direction of movement during forward self-motion.