Rapid Recalibration to Audiovisual Asynchrony

Abstract

To combine information from different sensory modalities, the brain must deal with considerable temporal uncertainty. In natural environments, an external event may produce simultaneous auditory and visual signals yet they will invariably activate the brain asynchronously due to different propagation speeds for light and sound, and different neural response latencies once the signals reach the receptors. One strategy the brain uses to deal with audiovisual timing variation is to adapt to a prevailing asynchrony to help realign the signals. Here, using psychophysical methods in human subjects, we investigate audiovisual recalibration and show that it takes place extremely rapidly without explicit periods of adaptation. Our results demonstrate that exposure to a single, brief asynchrony is sufficient to produce strong recalibration effects. Recalibration occurs regardless of whether the preceding trial was perceived as synchronous, and regardless of whether a response was required. We propose that this rapid recalibration is a fast-acting sensory effect, rather than a higher-level cognitiveprocess.Anaccountintermsofresponsebiasisunlikelyduetoastrongasymmetrywherebystimuliwithvisionleadingproducebigger recalibrations than audition leading. A fast-acting recalibration mechanism provides a means for overcoming inevitable audiovisual timing variation and serves to rapidly realign signals at onset to maximize the perceptual benefits of audiovisual integration.

Children do not recalibrate motor-sensory temporal order after exposure to delayed sensory feedback

“…However, the results are not in immediate agreement with a recent study by Van der Burg, Alais and Cass (2013). They demonstrated a very rapid form of cross-modal adaptation, where the offset of the previous trial in a sequence of audio-visual presentations causes a negative aftereffect on the current trial.…”

Auditory frequency perception adapts rapidly to the immediate past

“…In cross-modal research (Alais, Newell, & Mamassian, 2010), previous studies using the intertrial adaptation paradigm with audiovisual stimuli have shown the aftereffects are comparable in magnitude to those obtained with prolonged exposure paradigms (Harvey et al, 2014;Van der Burg et al, 2013Wozny & Shams, 2011) and that the effects are even present and strong when participants passively perceive the audiovisual stimuli (Van der . Although an early report suggested that the magnitude plateaus after 12-20 s of adaptation (Kay & Matthews, 1972), two subsequent studies investigating the time-course of the aftereffect concluded that the aftereffect accrues rapidly in the first few minutes but does not saturate until 20-30 minutes (Regan & Tansley, 1979;Tansley & Suffield, 1983).…”

“…This improves efficiency as no time is lost in timeconsuming adaptation periods and every trial provides data. Moreover, as recent multisensory studies of intertrial adaptation have shown in both the spatial (Wozny & Shams, 2011) and temporal (Harvey, Van der Burg, & Alais, 2014; Van der Burg et al, 2013;Van der Burg, Orchard-Mills, & Alais, 2014) domains, adaptation effects are evident after a single brief trial. This challenges the assumption in traditional adaptation studies that prolonged exposure to an adaptor is necessary to produce reliable perceptual aftereffects.…”

“…1a) of the glide direction responses to determine whether the PSC on a given trial is influenced by exposure to the preceding trial's glide direction (see Van der Burg et al, 2013 for a similar methodology). Thus, separate distributions are plotted for trials in which the previous trial was a downward glide and for trials in which the previous trial was an upward glide.…”

“…Two recent multisensory studies have adopted an alternative approach based on intertrial analyses and shown that adaptation can be induced and tested extremely rapidly (Van der Burg, Alais, & Cass, 2013;Wozny & Shams, 2011). In this approach, stimuli are presented in a series of rapid trials with each briefly presenting the stimulus at a level randomly drawn from a range sufficient to measure a threshold.…”