Auditory space perception - accuracy of distance and direction localization in blind and sighted

Abstract

Perception of space is based on a synthesis of information from multiple senses. During space perception, blind people mostly rely on information from auditory and haptic senses. The aim of present study was to verify the assumption that auditory sense is more sensitive in blind, as a consequence of intensive usage. Sensitivity is measured trough accuracy in spatial localization of auditory source. We had 15 blind and 15 sighted participants in research. They were exposed to a specific sound in 3 sessions, from 10 different positions, gained by combining two distances (1 m and 3 m) and five directions (straight ahead, 15 degrees and 30 degrees left and right from the participant). Participants' task was to listen to a sound and then to detect whether it was positioned on a nearer of further distance and whether it was from straight ahead, left or right from them. Analysis showed that perceived stimuli distance accuracy depends on stimuli distance. Participants were more precise in estimating distance for those stimuli which were further away. Perceived stimuli direction accuracy depends on the stimuli direction in such a way that the more extreme left or right stimulus is, participants are more certain in estimating its direction. However, perceived stimuli direction accuracy also depends on whether the participant is blind or sighted, in such a way that blind participants are better in the localization of sound direction. Hence, between blind and sighted participants there are some differences in sound source localization accuracy, which supports the claim that auditory sense sensitivity increases in blind participants.