Abstract
Ventriloquism refers to a perceptual phenomenon in which the apparent location of a sound source is displaced in the direction of a synchronous but spatially disparate visual stimulus. It is generally accepted that spatial and temporal proximity are factors facilitating crossmodal integration. Here we investigate whether content based processes could also play a role. In order to control for strategic factors, a psychophysical staircase method (Bertelson and Aschersleben, 1998) was adopted. Auditory stimuli were digital recordings of vowels (/i/ and /o/). Visual stimuli were digital pictures of talking faces articulating the same vowels, and a scrambled face. We ran eight concurrent staircases. In half of these the auditory stimuli were paired with the corresponding face, and in the other half with the scrambled face. Half the staircases started from the extreme left and the other from the extreme right. Presentation of staircases was randomized. Participants were asked to judge whether the sound was coming from the left, or from the right, of the median plane. On the staircases with a face stimulus, reversals started to occur significantly earlier than with a nonface. Thus, a ‘‘realistic’’ stimulus pairing enhances crossmodal integration.
