Predicting auditory space calibration from recent multisensory experience

Abstract

Multisensory experience can lead to auditory space recalibration. After exposure to discrepant audiovisual stimulation, sound percepts are displaced in space, in the direction of the previous visual stimulation. This study focuses on identifying the factors in recent sensory experience leading to such auditory space shifts. Sequences of five audiovisual pairs were presented, each randomly congruent or discrepant in space. Each sequence was followed by a single auditory trial and two visual trials. In each trial, participants had to identify the perceived stimuli positions. We found that auditory localization is shifted during audiovisual discrepant trials and during subsequent auditory trials, suggesting a recalibration effect. Time did not lead to greater recalibration effects. The last audiovisual trial affects the subsequent auditory shift the most. The number of discrepant trials in a sequence, and the number of consecutive trials in sequence, also correlated with the subsequent auditory shift. To estimate the individual contribution of previously presented trials to the recalibration effect, a best-fitting model was developed to predict the shift in a linear weighted combination of stimulus features: (1) whether matching or discrepant trials occurred in the sequence, (2) total number of discrepant trials, and (3) maximum number of consecutive discrepant trials, (4) whether the last trial was discrepant or not. The selected model consists of a function including as properties the type of stimulus of the last audiovisual sequence trial and the overall probability of mismatching trials in sequence.

On recent findings and clarifications regarding the ventriloquist aftereffect

“…localization shift" and "This finding is in line with that by Wozny and Shams". Finding 2, according to which the recalibration was enhanced by increasing the number of recent discrepancies in a consistent direction, was shown as a clear correlation (r 2 = 0.33, p = 0.02) by Mendonça et al (2015). The same tendency was suggested by Wozny and Shams (2011), in Fig.…”

“…Regarding finding 3, about the most recent AV event having the largest influence on the recalibration, this was clearly shown by Mendonça et al (2015). Indeed, none of the audiovisual events prior to the last had a statistically significant effect on the recalibration.…”

“…Therefore, it may be suspected that the slight tendency presented in the figure was not statistically significant. In an attempt to clarify who found what, one could state that Wozny and Shams (2011) suggested the possible existence of an effect that was demonstrated by Mendonça et al (2015).…”

“…In their clarification letter, Frane and Shams (2015) begin by stating that several findings by Mendonça et al (2015) were replications of findings by Wozny and Shams (2011), namely: (1) "recalibration occurred rapidly, after exposure, and without feedback"; (2) "recalibration was enhanced by increasing the number of recent discrepancies in a consistent direction"; (3) "the most audiovisual (AV) exposure had the greatest influence on recalibration"; and (4) among recent AV exposures, earlier exposures had lingering influence on recalibration, but had less influence than later exposures in the sequence.…”

“…Finally, Frane and Shams (2015) describe a finding 4 according to which, among recent AV exposures, earlier exposures had lingering influence on recalibration, but Mendonça et al (2015) analyzed the impact of different sequences of audiovisual events on the posterior localization of sounds. Recently, Frane and Shams (2015) issued a Letter to the Editor of this Journal with the intention of presenting further clarifications of that study and its relation to another study by Wozny and Shams (2011).…”