Combining visual and auditory information

Robust perception requires that information from by our five different senses be combined at some central level to produce a single unified percept of the world. Recent theory and evidence from many laboratories suggests that the combination does not occur in a rigid, hardwired fashion, but follows flexible situation-dependent rules that allow information to be combined with maximal efficiency. In this review we discuss recent evidence from our laboratories investigating how information from auditory and visual modalities is combined. The results support the notion of Bayesian combination. We also examine temporal alignment of auditory and visual signals, and show that perceived simultaneity does not depend solely on neural latencies, but involves active processes that compensate, for example, for the physical delay introduced by the relatively slow speed of sound. Finally, we go on to show that although visual and auditory information is combined to maximize efficiency, attentional resources for the two modalities are largely independent.