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Limits of Perceived Audio-Visual Spatial Coherence as Defined by Reaction Time Measurements

Stenzel, Hanne, Francombe, Jon and Jackson, Philip J. B. (2019) Limits of Perceived Audio-Visual Spatial Coherence as Defined by Reaction Time Measurements Frontiers in Neuroscience, 13 (451).

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The ventriloquism effect describes the phenomenon of audio and visual signals with common features, such as a voice and a talking face merging perceptually into one percept even if they are spatially misaligned. The boundaries of the fusion of spatially misaligned stimuli are of interest for the design of multimedia products to ensure a perceptually satisfactory product. They have mainly been studied using continuous judgment scales and forced-choice measurement methods. These results vary greatly between different studies. The current experiment aims to evaluate audio-visual fusion using reaction time (RT) measurements as an indirect method of measurement to overcome these great variances. A two-alternative forced-choice (2AFC) word recognition test was designed and tested with noise and multi-talker speech background distractors. Visual signals were presented centrally and audio signals were presented between 0° and 31° audio-visual offset in azimuth. RT data were analyzed separately for the underlying Simon effect and attentional effects. In the case of the attentional effects, three models were identified but no single model could explain the observed RTs for all participants so data were grouped and analyzed accordingly. The results show that significant differences in RTs are measured from 5° to 10° onwards for the Simon effect. The attentional effect varied at the same audio-visual offset for two out of the three defined participant groups. In contrast with the prior research, these results suggest that, even for speech signals, small audio-visual offsets influence spatial integration subconsciously.

Item Type: Article
Divisions : Faculty of Engineering and Physical Sciences > Electronic Engineering
Authors :
Jackson, Philip J.
Date : 22 May 2019
Funders : EPSRC - Engineering and Physical Sciences Research Council
DOI : 10.3389/fnins.2019.00451
Grant Title : Future Spatial Audio for an Immersive Listener
Copyright Disclaimer : Copyright © 2019 Stenzel, Francombe and Jackson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Frontiers
Uncontrolled Keywords : Ventriloquism; Simon effect; Spatial correspondence; Reaction times; Sudio-visual
Depositing User : Diane Maxfield
Date Deposited : 01 Jul 2019 14:10
Last Modified : 01 Jul 2019 14:10

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