Abstract
Audition and vision both contribute to the perception of an event, and when the auditory stimulus is rich, auditory information can exert a powerful influence on multimodal perception. Previous research (Ecker and Heller, Perception 2005) found that auditory information which indicates rolling surface contact can strongly influence whether or not a visually displayed ball is perceived as rolling. In the experiments to be presented here, a quantitative approach was taken to assess the relative contribution of audition and vision on the perceived speed of a rolling ball. A video of a ball rolling in depth was paired with the sound of a ball rolling. In a 2IFC comparison, observers indicated which ball seemed faster. When the near-threshold visual and auditory speed information was consistent, performance improved as much as would be predicted by a linear model. On the other half of the trials in which the auditory and visual information were inconsistent, performance declined accordingly. Results are compared with a straightforward model of the optimal linear combination of information from independent channels in which we assume that the combination of auditory and visual information is obligatory.
Supported by NSF BCS-0446955