Speeded responses to audiovisual signal changes result from bimodal integration.

Integration of auditory and visual information was studied in humans detecting targets (i.e., location changes of the auditory, the visual, or both parts of a repetitively presented audiovisual stimulus). Behavioral results suggest that the time advantage to bimodal compared with unimodal targets was due to combined rather than separate processing of the auditory and the visual target information. Event-related brain potential results revealed strong audiovisual interactions supporting interactive and not independent coactivation models. The time course of this interaction suggests that the audiovisual integration occurred after low-level, sensory processing but well before the execution of the motor response.