Perceived Audio-Visual Simultaneity Is Recalibrated by the Visual Intensity of the Preceding Trial.

A vital heuristic used when making judgements on whether audio-visual signals arise from the same event, is the temporal coincidence of the respective signals. Previous research has highlighted a process, whereby the perception of simultaneity rapidly recalibrates to account for differences in the physical temporal offsets of stimuli. The current paper investigated whether rapid recalibration also occurs in response to differences in central arrival latencies, driven by visual-intensity-dependent processing times. In a behavioural experiment, observers completed a temporal-order judgement (TOJ), simultaneity judgement (SJ) and simple reaction-time (RT) task and responded to audio-visual trials that were preceded by other audio-visual trials with either a bright or dim visual stimulus. It was found that the point of subjective simultaneity shifted, due to the visual intensity of the preceding stimulus, in the TOJ, but not SJ task, while the RT data revealed no effect of preceding intensity. Our data therefore provide some evidence that the perception of simultaneity rapidly recalibrates based on stimulus intensity.