Localization performance is enhanced under bimodal conditions of the auditory and visual spatial channels

Abstract

A sequential localization task compared the effects of unimodal versus bimodal spatial acuity in the auditory and visual perceptual systems. The four subjects were tested in a two‐alternative forced‐choice, three down–one up adaptive paradigm in which two 200‐ms signals were presented sequentially with a 1000‐ms inter‐stimulus interval. Tests were administered with a 620‐nm light emitting diode at a luminance level of 200 ml and a 1.0‐kHz high‐pass noise at 57 dB (A‐weighted). The minimum bimodal angle (MBA) threshold was compared to that of the minimum visible angle (MVA) and minimum audible angle (MAA) thresholds and found to increase performance significantly over the single mode localization tasks, except at 0‐deg azimuth that equaled the MVA for most subjects. The implications of these results are discussed.