We asked whether bilinguals’ benefits reach beyond the auditory modality to benefit multisensory processing. We measured audiovisual integration of auditory and visual cues in monolinguals and bilinguals via the double-flash illusion where the presentation of multiple auditory stimuli concurrent with a single visual flash induces an illusory perception of multiple flashes. We varied stimulus onset asynchrony (SOA) between auditory and visual cues to measure the “temporal binding window” where listeners fuse a single percept. Bilinguals showed faster responses and were less susceptible to the double-flash illusion than monolinguals. Moreover, monolinguals showed poorer sensitivity in AV processing compared to bilinguals. The width of bilinguals’ AV temporal integration window was narrower than monolinguals’ for both leading and lagging SOAs (Biling.: -65–112 ms; Mono.: -193 – 112 ms). Our results suggest the plasticity afforded by speaking multiple languages enhances multisensory integration and audiovisual binding in the bilingual brain.

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.