An assessment of virtual auditory distance judgments among blind and sighted listeners

Abstract

Auditory distance perception is a crucial component of blind listeners’ spatial awareness. Many studies have reported supra-normal spatial auditory abilities among blind individuals, such as enhanced azimuthal localization [Voss et al. (2004)] and distance discrimination [Kolarik et al. (in press)]. However, it is not known whether blind listeners are better able to use acoustic information to enhance judgments of distance to single sound sources, or whether lack of visual spatial cues prevents calibration of auditory distance information, leading to worse performance than for sighted listeners. Blind and sighted listeners were presented with single, stationary virtual sound sources between 1.22 and 13.79 m away in a virtual anechoic environment simulated using an image-source model. Stimuli were spoken sentences. Sighted listeners systematically underestimated distance to remote virtual sources, while blind listeners overestimated the distance to nearby virtual sources and underestimated it for remote virtual sources. The findings suggest that blind listeners are less accurate at judging absolute distance, and experience a compression of the auditory world, relative to sighted listeners. The results support a perceptual deficiency hypothesis for absolute distance judgments, suggesting that compensatory processes for audition do not develop among blind listeners when estimating the distance to single, stationary sound sources.