Selective attention determines the direction of audiovisual temporal recalibration

Nara Ikumi, Salvador Soto-Faraco

Last modified: 2013-05-05

Abstract


Coherent perception of multimodal events requires the adjustment of temporal discrepancies between information from different sensory modalities. Temporal recalibration by adaptation to asynchrony has been proposed as a mechanism to compensate for these timing differences. However, most of the studies to date have examined recalibration on isolated crossmodal events. Considering the rich complexity of everyday life sensory environments, it seems crucial to investigate how the brain selects which stimuli, of all possible events falling within the same temporal window, should be adjusted in time. Here, we hypothesize that attention might provide an effective filter to help resolve which stimuli are selected when multiple events compete for recalibration. To test this we used an audiovisual recalibration paradigm in which two alternative asynchronies were present during the adaptation. The exposure phase consisted of a repetitive sequence of flash-tone-flash, and we manipulated the direction of attention to one of two visual events. In the test phase, following exposure, we found a shift in the point of subjective simultaneity (PSS) depending on the direction of attention, in otherwise physically identical adaptation conditions. A follow up experiment where temporal attention was deployed at alternate temporal positions revealed that recalibration aftereffects are also driven by stimulus properties. These results suggest that attention to specific stimuli promotes certain audiovisual pairings events to be combined and subsequently adjusted in time. Furthermore, we speculate that the resolution of recalibration in complex scenes involves the orchestration between top-down selection mechanisms and stimulus-driven processes.

Keywords


temporal recalibration; audiovisual simultaneity; attention

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