Estimating sound source distance with and without vision

Background. Visual capture is an important perceptual phenomenon in which the spatial location of a visual target influences the perceived location of a related auditory target. Little is known about visual capture in a distance dimension. Methods. Two groups of listeners judged the apparent distances of five loudspeaker sound sources, extending from 1 to 5 m. In one group, each listener was allowed to view the loudspeaker array. In the second group, listeners were blindfolded for the duration of the experiment. Results. No visual capture effects were observed. Instead, the addition of vision was found to both improve distance judgment accuracy and lower judgment variability compared with the auditory-only stimulus. Auditory-only accuracy was found to substantially improve over the course of the experiment, however. Conclusions. Visual capture in distance is perhaps less general than suggested by past research, a result that has important implications for the display of spatial layout under conditions where vision is either missing or degraded.