Partial visual loss disrupts the relationship between judged room size and sound source distance

Andrew J Kolarik,Shahina Pardhan,Brian C J Moore,Silvia Cirstea,Sarika Gopalakrishnan,Rajiv Raman

doi:10.1007/s00221-021-06235-0

Abstract

Visual spatial information plays an important role in calibrating auditory space. Blindness results in deficits in a number of auditory abilities, which have been explained in terms of the hypothesis that visual information is needed to calibrate audition. When judging the size of a novel room when only auditory cues are available, normally sighted participants may use the location of the farthest sound source to infer the nearest possible distance of the far wall. However, for people with partial visual loss (distinct from blindness in that some vision is present), such a strategy may not be reliable if vision is needed to calibrate auditory cues for distance. In the current study, participants were presented with sounds at different distances (ranging from 1.2 to 13.8 m) in a simulated reverberant (T60 = 700 ms) or anechoic room. Farthest distance judgments and room size judgments (volume and area) were obtained from blindfolded participants (18 normally sighted, 38 partially sighted) for speech, music, and noise stimuli. With sighted participants, the judged room volume and farthest sound source distance estimates were positively correlated (p < 0.05) for all conditions. Participants with visual losses showed no significant correlations for any of the conditions tested. A similar pattern of results was observed for the correlations between farthest distance and room floor area estimates. Results demonstrate that partial visual loss disrupts the relationship between judged room size and sound source distance that is shown by sighted participants.

Highlights

Estimation of the three-dimensional characteristics of a room, such as its layout and its size, plays an important role in orientation (Loomis et al 1993), path planning (Kolarik et al 2016b, 2017c), and safe navigation (Hackney et al 2014; Kolarik et al 2016c)
The main findings of this study are: 1) For participants with visual impairment (VI), there were no significant correlations between acoustically judged room size and judged farthest sound source distance, whereas for sighted participants significant correlations were found
These findings are consistent with the perceptual deficiency hypothesis, suggesting that the use of a degraded visual signal to calibrate audition can interfere with the relationship between the estimated farthest sound distance and the room size

Summary

Introduction

Estimation of the three-dimensional characteristics of a room, such as its layout and its size, plays an important role in orientation (Loomis et al 1993), path planning (Kolarik et al 2016b, 2017c), and safe navigation (Hackney et al 2014; Kolarik et al 2016c). Blind participants have been shown to display marked deficits for tasks involving absolute judgments (Kolarik et al 2017a), spatial bisection (Gori et al 2014), the localization of sounds in elevation (Zwiers et al 2001; Lewald 2002), and perception of the location of a sound source in relation to external auditory landmarks (Vercillo et al 2018) These poorer abilities have been accounted for in terms of the perceptual deficiency hypothesis, which suggests that an intact visual signal is required to accurately calibrate audition, without which auditory spatial performance is worse (Axelrod 1959; Jones 1975). Participants made spatial judgments in simulated anechoic and reverberant rooms, to investigate whether the room reflections influenced the relationship between auditory distance estimates and room size judgments in participants with a range of severities of VI

Methods

Participants

Severe visual impairment

Procedures

Results

Discussion