No effect of auditory-visual spatial disparity on temporal recalibration

Abstract

It is known that the brain adaptively recalibrates itself to small (approximately 100 ms) auditory-visual (AV) temporal asynchronies so as to maintain intersensory temporal coherence. Here we explored whether spatial disparity between a sound and light affects AV temporal recalibration. Participants were exposed to a train of asynchronous AV stimulus pairs (sound-first or light-first) with sounds and lights emanating from either the same or a different location. Following a short exposure phase, participants were tested on an AV temporal order judgement (TOJ) task. Temporal recalibration manifested itself as a shift of subjective simultaneity in the direction of the adapted audiovisual lag. The shift was equally big when exposure and test stimuli were presented from the same or different locations. These results provide strong evidence for the idea that spatial co-localisation is not a necessary constraint for intersensory pairing to occur.

Fig. 1

Schematic illustration of the experimental conditions. In the exposure phase, the subject was exposed to a sound–light pair with 100 ms temporal offset (either sound-first or light first). During exposure, sounds were either presented from central (a, c) or lateral location (b, d). In the test phase, sound–light pairs were presented with a particular SOA ranging between −240 and 240 ms, with negative values indicating that the sound was presented first. Sounds of the test-stimulus pair either came from central (a, b) or lateral location (c, d )

Fig. 2

The proportions of visual-first responses (V-first) for each exposure lag (−100 ms sound-first, 100 ms light-first) for each combination of location of exposure sound (central, lateral) and location of the test sound (central, lateral)