scholarly journals Early and late beta-band power reflect audiovisual perception in the McGurk illusion

2015 ◽  
Vol 113 (7) ◽  
pp. 2342-2350 ◽  
Author(s):  
Yadira Roa Romero ◽  
Daniel Senkowski ◽  
Julian Keil

The McGurk illusion is a prominent example of audiovisual speech perception and the influence that visual stimuli can have on auditory perception. In this illusion, a visual speech stimulus influences the perception of an incongruent auditory stimulus, resulting in a fused novel percept. In this high-density electroencephalography (EEG) study, we were interested in the neural signatures of the subjective percept of the McGurk illusion as a phenomenon of speech-specific multisensory integration. Therefore, we examined the role of cortical oscillations and event-related responses in the perception of congruent and incongruent audiovisual speech. We compared the cortical activity elicited by objectively congruent syllables with incongruent audiovisual stimuli. Importantly, the latter elicited a subjectively congruent percept: the McGurk illusion. We found that early event-related responses (N1) to audiovisual stimuli were reduced during the perception of the McGurk illusion compared with congruent stimuli. Most interestingly, our study showed a stronger poststimulus suppression of beta-band power (13–30 Hz) at short (0–500 ms) and long (500–800 ms) latencies during the perception of the McGurk illusion compared with congruent stimuli. Our study demonstrates that auditory perception is influenced by visual context and that the subsequent formation of a McGurk illusion requires stronger audiovisual integration even at early processing stages. Our results provide evidence that beta-band suppression at early stages reflects stronger stimulus processing in the McGurk illusion. Moreover, stronger late beta-band suppression in McGurk illusion indicates the resolution of incongruent physical audiovisual input and the formation of a coherent, illusory multisensory percept.

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246986
Author(s):  
Alma Lindborg ◽  
Tobias S. Andersen

Speech is perceived with both the ears and the eyes. Adding congruent visual speech improves the perception of a faint auditory speech stimulus, whereas adding incongruent visual speech can alter the perception of the utterance. The latter phenomenon is the case of the McGurk illusion, where an auditory stimulus such as e.g. “ba” dubbed onto a visual stimulus such as “ga” produces the illusion of hearing “da”. Bayesian models of multisensory perception suggest that both the enhancement and the illusion case can be described as a two-step process of binding (informed by prior knowledge) and fusion (informed by the information reliability of each sensory cue). However, there is to date no study which has accounted for how they each contribute to audiovisual speech perception. In this study, we expose subjects to both congruent and incongruent audiovisual speech, manipulating the binding and the fusion stages simultaneously. This is done by varying both temporal offset (binding) and auditory and visual signal-to-noise ratio (fusion). We fit two Bayesian models to the behavioural data and show that they can both account for the enhancement effect in congruent audiovisual speech, as well as the McGurk illusion. This modelling approach allows us to disentangle the effects of binding and fusion on behavioural responses. Moreover, we find that these models have greater predictive power than a forced fusion model. This study provides a systematic and quantitative approach to measuring audiovisual integration in the perception of the McGurk illusion as well as congruent audiovisual speech, which we hope will inform future work on audiovisual speech perception.


2020 ◽  
Author(s):  
Jonathan E Peelle ◽  
Brent Spehar ◽  
Michael S Jones ◽  
Sarah McConkey ◽  
Joel Myerson ◽  
...  

In everyday conversation, we usually process the talker's face as well as the sound of their voice. Access to visual speech information is particularly useful when the auditory signal is degraded. Here we used fMRI to monitor brain activity while adults (n = 60) were presented with visual-only, auditory-only, and audiovisual words. As expected, audiovisual speech perception recruited both auditory and visual cortex, with a trend towards increased recruitment of premotor cortex in more difficult conditions (for example, in substantial background noise). We then investigated neural connectivity using psychophysiological interaction (PPI) analysis with seed regions in both primary auditory cortex and primary visual cortex. Connectivity between auditory and visual cortices was stronger in audiovisual conditions than in unimodal conditions, including a wide network of regions in posterior temporal cortex and prefrontal cortex. Taken together, our results suggest a prominent role for cross-region synchronization in understanding both visual-only and audiovisual speech.


2017 ◽  
Vol 60 (1) ◽  
pp. 144-158 ◽  
Author(s):  
Ana A. Francisco ◽  
Alexandra Jesse ◽  
Margriet A. Groen ◽  
James M. McQueen

Purpose Because reading is an audiovisual process, reading impairment may reflect an audiovisual processing deficit. The aim of the present study was to test the existence and scope of such a deficit in adult readers with dyslexia. Method We tested 39 typical readers and 51 adult readers with dyslexia on their sensitivity to the simultaneity of audiovisual speech and nonspeech stimuli, their time window of audiovisual integration for speech (using incongruent /aCa/ syllables), and their audiovisual perception of phonetic categories. Results Adult readers with dyslexia showed less sensitivity to audiovisual simultaneity than typical readers for both speech and nonspeech events. We found no differences between readers with dyslexia and typical readers in the temporal window of integration for audiovisual speech or in the audiovisual perception of phonetic categories. Conclusions The results suggest an audiovisual temporal deficit in dyslexia that is not specific to speech-related events. But the differences found for audiovisual temporal sensitivity did not translate into a deficit in audiovisual speech perception. Hence, there seems to be a hiatus between simultaneity judgment and perception, suggesting a multisensory system that uses different mechanisms across tasks. Alternatively, it is possible that the audiovisual deficit in dyslexia is only observable when explicit judgments about audiovisual simultaneity are required.


2011 ◽  
Vol 24 (1) ◽  
pp. 67-90 ◽  
Author(s):  
Riikka Möttönen ◽  
Kaisa Tiippana ◽  
Mikko Sams ◽  
Hanna Puharinen

AbstractAudiovisual speech perception has been considered to operate independent of sound location, since the McGurk effect (altered auditory speech perception caused by conflicting visual speech) has been shown to be unaffected by whether speech sounds are presented in the same or different location as a talking face. Here we show that sound location effects arise with manipulation of spatial attention. Sounds were presented from loudspeakers in five locations: the centre (location of the talking face) and 45°/90° to the left/right. Auditory spatial attention was focused on a location by presenting the majority (90%) of sounds from this location. In Experiment 1, the majority of sounds emanated from the centre, and the McGurk effect was enhanced there. In Experiment 2, the major location was 90° to the left, causing the McGurk effect to be stronger on the left and centre than on the right. Under control conditions, when sounds were presented with equal probability from all locations, the McGurk effect tended to be stronger for sounds emanating from the centre, but this tendency was not reliable. Additionally, reaction times were the shortest for a congruent audiovisual stimulus, and this was the case independent of location. Our main finding is that sound location can modulate audiovisual speech perception, and that spatial attention plays a role in this modulation.


2018 ◽  
Vol 31 (1-2) ◽  
pp. 19-38 ◽  
Author(s):  
John F. Magnotti ◽  
Debshila Basu Mallick ◽  
Michael S. Beauchamp

We report the unexpected finding that slowing video playback decreases perception of the McGurk effect. This reduction is counter-intuitive because the illusion depends on visual speech influencing the perception of auditory speech, and slowing speech should increase the amount of visual information available to observers. We recorded perceptual data from 110 subjects viewing audiovisual syllables (either McGurk or congruent control stimuli) played back at one of three rates: the rate used by the talker during recording (the natural rate), a slow rate (50% of natural), or a fast rate (200% of natural). We replicated previous studies showing dramatic variability in McGurk susceptibility at the natural rate, ranging from 0–100% across subjects and from 26–76% across the eight McGurk stimuli tested. Relative to the natural rate, slowed playback reduced the frequency of McGurk responses by 11% (79% of subjects showed a reduction) and reduced congruent accuracy by 3% (25% of subjects showed a reduction). Fast playback rate had little effect on McGurk responses or congruent accuracy. To determine whether our results are consistent with Bayesian integration, we constructed a Bayes-optimal model that incorporated two assumptions: individuals combine auditory and visual information according to their reliability, and changing playback rate affects sensory reliability. The model reproduced both our findings of large individual differences and the playback rate effect. This work illustrates that surprises remain in the McGurk effect and that Bayesian integration provides a useful framework for understanding audiovisual speech perception.


2019 ◽  
Author(s):  
Violet Aurora Brown ◽  
Julia Feld Strand

The McGurk effect is a multisensory phenomenon in which discrepant auditory and visual speech signals typically result in an illusory percept (McGurk & MacDonald, 1976). McGurk stimuli are often used in studies assessing the attentional requirements of audiovisual integration (e.g., Alsius et al., 2005), but no study has directly compared the costs associated with integrating congruent versus incongruent audiovisual speech. Some evidence suggests that the McGurk effect may not be representative of naturalistic audiovisual speech processing—susceptibility to the McGurk effect is not associated with the ability to derive benefit from the addition of the visual signal (Van Engen et al., 2017), and distinct cortical regions are recruited when processing congruent versus incongruent speech (Erickson et al., 2014). In two experiments, one using response times to identify congruent and incongruent syllables and one using a dual-task paradigm, we assessed whether congruent and incongruent audiovisual speech incur different attentional costs. We demonstrated that response times to both the speech task (Experiment 1) and a secondary vibrotactile task (Experiment 2) were indistinguishable for congruent compared to incongruent syllables, but McGurk fusions were responded to more quickly than McGurk non-fusions. These results suggest that despite documented differences in how congruent and incongruent stimuli are processed (Erickson et al., 2014; Van Engen, Xie, & Chandrasekaran, 2017), they do not appear to differ in terms of processing time or effort. However, responses that result in McGurk fusions are processed more quickly than those that result in non-fusions, though attentional cost is comparable for the two response types.


Author(s):  
Dominic W. Massaro ◽  
Alexandra Jesse

This article gives an overview of the main research questions and findings unique to audiovisual speech perception research, and discusses what general questions about speech perception and cognition the research in this field can answer. The influence of a second perceptual source in audiovisual speech perception compared to auditory speech perception immediately necessitates the question of how the information from the different perceptual sources is used to reach the best overall decision. The article explores how our understanding of speech benefits from having the speaker's face present, and how this benefit makes transparent the nature of speech perception and word recognition. Modern communication methods such as Voice over Internet Protocol find a wide acceptance, but people are reluctant to forfeit face-to-face communication. The article also considers the role of visual speech as a language-learning tool in multimodal training, information and information processing in audiovisual speech perception, lexicon and word recognition, facial information for speech perception, and theories of audiovisual speech perception.


2018 ◽  
Vol 31 (1-2) ◽  
pp. 7-18 ◽  
Author(s):  
John MacDonald

In 1976 Harry McGurk and I published a paper in Nature, entitled ‘Hearing Lips and Seeing Voices’. The paper described a new audio–visual illusion we had discovered that showed the perception of auditorily presented speech could be influenced by the simultaneous presentation of incongruent visual speech. This hitherto unknown effect has since had a profound impact on audiovisual speech perception research. The phenomenon has come to be known as the ‘McGurk effect’, and the original paper has been cited in excess of 4800 times. In this paper I describe the background to the discovery of the effect, the rationale for the generation of the initial stimuli, the construction of the exemplars used and the serendipitous nature of the finding. The paper will also cover the reaction (and non-reaction) to the Nature publication, the growth of research on, and utilizing the ‘McGurk effect’ and end with some reflections on the significance of the finding.


2020 ◽  
Author(s):  
Aisling E. O’Sullivan ◽  
Michael J. Crosse ◽  
Giovanni M. Di Liberto ◽  
Alain de Cheveigné ◽  
Edmund C. Lalor

AbstractSeeing a speaker’s face benefits speech comprehension, especially in challenging listening conditions. This perceptual benefit is thought to stem from the neural integration of visual and auditory speech at multiple stages of processing, whereby movement of a speaker’s face provides temporal cues to auditory cortex, and articulatory information from the speaker’s mouth can aid recognizing specific linguistic units (e.g., phonemes, syllables). However it remains unclear how the integration of these cues varies as a function of listening conditions. Here we sought to provide insight on these questions by examining EEG responses to natural audiovisual, audio, and visual speech in quiet and in noise. Specifically, we represented our speech stimuli in terms of their spectrograms and their phonetic features, and then quantified the strength of the encoding of those features in the EEG using canonical correlation analysis. The encoding of both spectrotemporal and phonetic features was shown to be more robust in audiovisual speech responses then what would have been expected from the summation of the audio and visual speech responses, consistent with the literature on multisensory integration. Furthermore, the strength of this multisensory enhancement was more pronounced at the level of phonetic processing for speech in noise relative to speech in quiet, indicating that listeners rely more on articulatory details from visual speech in challenging listening conditions. These findings support the notion that the integration of audio and visual speech is a flexible, multistage process that adapts to optimize comprehension based on the current listening conditions.Significance StatementDuring conversation, visual cues impact our perception of speech. Integration of auditory and visual speech is thought to occur at multiple stages of speech processing and vary flexibly depending on the listening conditions. Here we examine audiovisual integration at two stages of speech processing using the speech spectrogram and a phonetic representation, and test how audiovisual integration adapts to degraded listening conditions. We find significant integration at both of these stages regardless of listening conditions, and when the speech is noisy, we find enhanced integration at the phonetic stage of processing. These findings provide support for the multistage integration framework and demonstrate its flexibility in terms of a greater reliance on visual articulatory information in challenging listening conditions.


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