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Abstract

Multisensory integration allows us to integrate information from different senses, enhancing the ability to detect, locate and discriminate objects and events in the surroundings. The purpose of the present study is to examine whether the location and relative intensity of a seemingly irrelevant visual stimulus influences auditory localization. Subjects were asked to localize by pointing a sound in a condition in which a neutral visual stimulus was either suprathreshold (Experiment 1), or subthreshold (Experiment 2). In the crossmodal condition, the spatial disparity of the audio-visual stimuli was systematically varied. The results show that the efficacy of the visual information has substantially different effects on auditory localization with respect to visual capture and adherence to the spatial principle of multisensory integration. When the visual stimulus is presented suprathreshold, vision dominates and captures sound, regardless of the location of the visual stimulus. By contrast, a visual stimulus at threshold level improves auditory localization accuracy only when the two stimuli are spatially coincident.