Influence of auditory information on auditory‐visual speed discrimination

Auditory information can exert a strong influence on multimodal perception. In the experiments described here, a video of a ball rolling in depth was paired with the sound of a ball rolling. The speed of the balls’ roll in the video was independently varied from the speed of the balls’ roll in the soundtrack. Total duration was held constant so that the auditory cues to speed were ongoing spectro‐temporal features of the rolling sounds. In a 2IFC comparison, observers indicated which ball seemed to roll faster. In half of the trials the near‐threshold visual and auditory speed information was consistent, e.g., both the video and sound sped up between the first and second interval. 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.