Timing sight and sound

It has been proposed that there is a perceptual compensation for the difference between the speeds of light and sound. We examined this possibility using a range of auditory visual tasks, in which performance depends on the relative timing of auditory and visual information, and manipulated viewing distance to test for perceptual compensation. We explored auditory-visual integration, cross modal causal attributions, and auditory-visual temporal order judgments. We observed timing shifts with viewing distance following loudspeaker, but not headphone, presentations. We were unable to find reliable evidence of perceptual compensation. Our findings suggest that auditory and visual signals of an event that reach an observer at the same point in time tend to become perceptually bound, even when the sources of those signals could not have occurred together. (c) 2004 Elsevier Ltd. All rights reserved.