Splitting Time: Sound-Induced Illusory Visual Temporal Fission and Fusion

Auditory stimuli have been shown to alter visual temporal perception. For example, illusory temporal order is perceived when an auditory tone cues one side of space prior to the onset of simultaneously presented visual stimuli. Competing accounts attempt to explain such effects. The spatial gradient account of attention suggests speeded processing of visual stimuli in the cued space, whereas the impletion account suggests a Gestalt-like process where an attempt is made to arrive at a ‘realistic’ representation of an event given ambiguous conditions. Temporal ventriloquism – where visual temporal order judgement performance is enhanced when a spatially uninformative tone is presented prior to, and after, visual stimuli onset – argues that the temporal relationship of the auditory stimuli to visual stimuli, as well as the number of auditory stimuli equalling the visual stimuli, drives the mechanisms underlying these and related effects. Results from a series of experiments highlight putative inconsistencies in both the spatial gradient account of attention and the classical temporal ventriloquism account. We present novel behavioural effects – illusory temporal order via spatially uninformative tones, and illusory simultaneity via a single tone prior to visual stimuli onset – that can be accounted for by an expanded version of the impletion account.