Audiovisual sentence recognition not predicted by susceptibility to the McGurk effect

In noisy situations, visual information plays a critical role in the success of speech communication: listeners are better able to understand speech when they can see the speaker. Visual influence on auditory speech perception is also observed in the McGurk effect, in which discrepant visual information alters listeners’ auditory perception of a spoken syllable. When hearing /ba/ while seeing a person saying /ga/, for example, listeners may report hearing /da/. Because these two phenomena have been assumed to arise from a common integration mechanism, the McGurk effect has often been used as a measure of audiovisual integration in speech perception. In this study, we test whether this assumed relationship exists within individual listeners. We measured participants’ susceptibility to the McGurk illusion as well as their ability to identify sentences in noise across a range of signal-to-noise ratios in audio-only and audiovisual modalities. Our results do not show a relationship between listeners’ McGurk susceptibility and their ability to use visual cues to understand spoken sentences in noise, suggesting that McGurk susceptibility may not be a valid measure of audiovisual integration in everyday speech processing.     

Schizotypal traits are not related to multisensory integration or audiovisual speech perception

Multisensory integration, the binding of sensory information from different sensory modalities, may contribute to perceptual symptomatology in schizophrenia, including hallucinations and aberrant speech perception. Differences in multisensory integration and temporal processing, an important component of multisensory integration, are consistently found in schizophrenia. Evidence is emerging that these differences extend across the schizophrenia spectrum, including individuals in the general population with higher schizotypal traits. In the current study, we investigated the relationship between schizotypal traits and perceptual functioning, using audiovisual speech-in-noise, McGurk, and ternary synchrony judgment tasks. We measured schizotypal traits using the Schizotypal Personality Questionnaire (SPQ), hypothesizing that higher scores on Unusual Perceptual Experiences and Odd Speech subscales would be associated with decreased multisensory integration, increased susceptibility to distracting auditory speech, and less precise temporal processing. Surprisingly, these measures were not associated with the predicted subscales, suggesting that these perceptual differences may not be present across the schizophrenia spectrum.     

发展性阅读障碍视听时间整合缺陷可能的机制：视听时间再校准能力受损

发展性阅读障碍的本质一直是研究者争论的焦点。大量研究发现, 阅读障碍者具有视听时间整合缺陷。然而, 这些研究仅考察了阅读障碍者视听时间整合加工的整体表现, 也就是平均水平的表现, 却对整合加工的变化过程缺乏探讨。视听时间再校准反映了视听时间整合的动态加工过程, 对内部时间表征与感觉输入之间差异的再校准困难则会导致多感觉整合受损, 而阅读障碍者的再校准相关能力存在缺陷。因此, 视听时间再校准能力受损可能是发展性阅读障碍视听时间整合缺陷的根本原因。未来的研究需要进一步考察发展性阅读障碍者视听时间再校准能力的具体表现, 以及这些表现背后的认知神经机制。     

Crossmodal binding: Evaluating the “unity assumption” using audiovisual speech stimuli

We investigated whether the “unity assumption,” according to which an observer assumes that two different sensory signals refer to the same underlying multisensory event, influences the multisensory integration of audiovisual speech stimuli. Syllables (Experiments 1, 3, and 4) or words (Experiment 2) were presented to participants at a range of different stimulus onset asynchronies using the method of constant stimuli. Participants made unspeeded temporal order judgments regarding which stream (either auditory or visual) had been presented first. The auditory and visual speech stimuli in Experiments 1–3 were either gender matched (i.e., a female face presented together with a female voice) or else gender mismatched (i.e., a female face presented together with a male voice). In Experiment 4, different utterances from the same female speaker were used to generate the matched and mismatched speech video clips. Measuring in terms of the just noticeable difference the participants in all four experiments found it easier to judge which sensory modality had been presented first when evaluating mismatched stimuli than when evaluating the matched-speech stimuli. These results therefore provide the first empirical support for the “unity assumption” in the domain of the multisensory temporal integration of audiovisual speech stimuli.     

Crossmodal binding: evaluating the "unity assumption" using audiovisual speech stimuli

We investigated whether the "unity assumption," according to which an observer assumes that two different sensory signals refer to the same underlying multisensory event, influences the multisensory integration of audiovisual speech stimuli. Syllables (Experiments 1, 3, and 4) or words (Experiment 2) were presented to participants at a range of different stimulus onset asynchronies using the method of constant stimuli. Participants made unspeeded temporal order judgments regarding which stream (either auditory or visual) had been presented first. The auditory and visual speech stimuli in Experiments 1-3 were either gender matched (i.e., a female face presented together with a female voice) or else gender mismatched (i.e., a female face presented together with a male voice). In Experiment 4, different utterances from the same female speaker were used to generate the matched and mismatched speech video clips. Measuring in terms of the just noticeable difference the participants in all four experiments found it easier to judge which sensory modality had been presented first when evaluating mismatched stimuli than when evaluating the matched-speech stimuli. These results therefore provide the first empirical support for the "unity assumption" in the domain of the multisensory temporal integration of audiovisual speech stimuli.     

Integrating face and voice in person perception

Integration of information from face and voice plays a central role in our social interactions. It has been mostly studied in the context of audiovisual speech perception: integration of affective or identity information has received comparatively little scientific attention. Here, we review behavioural and neuroimaging studies of face-voice integration in the context of person perception. Clear evidence for interference between facial and vocal information has been observed during affect recognition or identity processing. Integration effects on cerebral activity are apparent both at the level of heteromodal cortical regions of convergence, particularly bilateral posterior superior temporal sulcus (pSTS), and at 'unimodal' levels of sensory processing. Whether the latter reflects feedback mechanisms or direct crosstalk between auditory and visual cortices is as yet unclear.     

视听跨通道信息的整合与冲突控制

多通道信息交互是指来自某个感觉通道的信息与另一感觉通道的信息相互作用、相互影响的一系列加工过程。主要包括两个方面：一是不同感觉通道的输入如何整合;二是跨通道信息的冲突控制。本文综述了视听跨通道信息整合与冲突控制的行为心理机制和神经机制,探讨了注意对视听信息整合与冲突控制的影响。未来需探究视听跨通道信息加工的脑网络机制,考察特殊群体的跨通道整合和冲突控制以帮助揭示其认知和社会功能障碍的机制。     

The influence of selective attention to auditory and visual speech on the integration of audiovisual speech information

Conflicting visual speech information can influence the perception of acoustic speech, causing an illusory percept of a sound not present in the actual acoustic speech (the McGurk effect). We examined whether participants can voluntarily selectively attend to either the auditory or visual modality by instructing participants to pay attention to the information in one modality and to ignore competing information from the other modality. We also examined how performance under these instructions was affected by weakening the influence of the visual information by manipulating the temporal offset between the audio and video channels (experiment 1), and the spatial frequency information present in the video (experiment 2). Gaze behaviour was also monitored to examine whether attentional instructions influenced the gathering of visual information. While task instructions did have an influence on the observed integration of auditory and visual speech information, participants were unable to completely ignore conflicting information, particularly information from the visual stream. Manipulating temporal offset had a more pronounced interaction with task instructions than manipulating the amount of visual information. Participants' gaze behaviour suggests that the attended modality influences the gathering of visual information in audiovisual speech perception.     

An acquired deficit of audiovisual speech processing

We report a 53-year-old patient (AWF) who has an acquired deficit of audiovisual speech integration, characterized by a perceived temporal mismatch between speech sounds and the sight of moving lips. AWF was less accurate on an auditory digit span task with vision of a speaker's face as compared to a condition in which no visual information from the lower face was available. He was slower in matching words to pictures when he saw congruent lip movements compared to no lip movements or non-speech lip movements. Unlike normal controls, he showed no McGurk effect. We propose that multisensory binding of audiovisual language cues can be selectively disrupted.     

Investigating the effects of inversion on configural processing with an audiovisual temporal-order judgment task

Research has shown that inversion is more detrimental to the perception of faces than to the perception of other types of visual stimuli. Inverting a face results in an impairment of configural information processing that leads to slowed early face processing and reduced accuracy when performance is tested in face recognition tasks. We investigated the effects of inverting speech and non-speech stimuli on audiovisual temporal perception. Upright and inverted audiovisual video clips of a person uttering syllables (experiments 1 and 2), playing musical notes on a piano (experiment 3), or a rhesus monkey producing vocalisations (experiment 4) were presented. Participants made unspeeded temporal-order judgments regarding which modality stream (auditory or visual) appeared to have been presented first. Inverting the visual stream did not have any effect on the sensitivity of temporal discrimination responses in any of the four experiments, thus implying that audiovisual temporal integration is resilient to the effects of orientation in the picture plane. By contrast, the point of subjective simultaneity differed significantly as a function of orientation only for the audiovisual speech stimuli but not for the non-speech stimuli or monkey calls. That is, smaller auditory leads were required for the inverted than for the upright-visual speech stimuli. These results are consistent with the longer processing latencies reported previously when human faces are inverted and demonstrates that the temporal perception of dynamic audiovisual speech can be modulated by changes in the physical properties of the visual speech (ie by changes in orientation).     

Processing of audiovisually congruent and incongruent speech in school‐age children with a history of specific language impairment: a behavioral and event‐related potentials study

Previous studies indicate that at least some aspects of audiovisual speech perception are impaired in children with specific language impairment (SLI). However, whether audiovisual processing difficulties are also present in older children with a history of this disorder is unknown. By combining electrophysiological and behavioral measures, we examined perception of both audiovisually congruent and audiovisually incongruent speech in school‐age children with a history of SLI (H‐SLI), their typically developing (TD) peers, and adults. In the first experiment, all participants watched videos of a talker articulating syllables ‘ba’, ‘da’, and ‘ga’ under three conditions – audiovisual (AV), auditory only (A), and visual only (V). The amplitude of the N1 (but not of the P2) event‐related component elicited in the AV condition was significantly reduced compared to the N1 amplitude measured from the sum of the A and V conditions in all groups of participants. Because N1 attenuation to AV speech is thought to index the degree to which facial movements predict the onset of the auditory signal, our findings suggest that this aspect of audiovisual speech perception is mature by mid‐childhood and is normal in the H‐SLI children. In the second experiment, participants watched videos of audivisually incongruent syllables created to elicit the so‐called McGurk illusion (with an auditory ‘pa’ dubbed onto a visual articulation of ‘ka’, and the expectant perception being that of ‘ta’ if audiovisual integration took place). As a group, H‐SLI children were significantly more likely than either TD children or adults to hear the McGurk syllable as ‘pa’ (in agreement with its auditory component) than as ‘ka’ (in agreement with its visual component), suggesting that susceptibility to the McGurk illusion is reduced in at least some children with a history of SLI. Taken together, the results of the two experiments argue against global audiovisual integration impairment in children with a history of SLI and suggest that, when present, audiovisual integration difficulties in this population likely stem from a later (non‐sensory) stage of processing.     

The role of facial colour and luminance in visual and audiovisual speech perception

We conducted four experiments to investigate the role of colour and luminance information in visual and audiovisual speech perception. In experiments 1a (stimuli presented in quiet conditions) and 1b (stimuli presented in auditory noise), face display types comprised naturalistic colour (NC), grey-scale (GS), and luminance inverted (LI) faces. In experiments 2a (quiet) and 2b (noise), face display types comprised NC, colour inverted (CI), LI, and colour and luminance inverted (CLI) faces. Six syllables and twenty-two words were used to produce auditory and visual speech stimuli. Auditory and visual signals were combined to produce congruent and incongruent audiovisual speech stimuli. Experiments 1a and 1b showed that perception of visual speech, and its influence on identifying the auditory components of congruent and incongruent audiovisual speech, was less for LI than for either NC or GS faces, which produced identical results. Experiments 2a and 2b showed that perception of visual speech, and influences on perception of incongruent auditory speech, was less for LI and CLI faces than for NC and CI faces (which produced identical patterns of performance). Our findings for NC and CI faces suggest that colour is not critical for perception of visual and audiovisual speech. The effect of luminance inversion on performance accuracy was relatively small (5%), which suggests that the luminance information preserved in LI faces is important for the processing of visual and audiovisual speech.     

Audiovisual speech from emotionally expressive and lateralized faces

Emotional expression and how it is lateralized across the two sides of the face may influence how we detect audiovisual speech. To investigate how these components interact we conducted experiments comparing the perception of sentences expressed with happy, sad, and neutral emotions. In addition we isolated the facial asymmetries for affective and speech processing by independently testing the two sides of a talker's face. These asymmetrical differences were exaggerated using dynamic facial chimeras in which left- or right-face halves were paired with their mirror image during speech production. Results suggest that there are facial asymmetries in audiovisual speech such that the right side of the face and right-facial chimeras supported better speech perception than their left-face counterparts. Affective information was also found to be critical in that happy expressions tended to improve speech performance on both sides of the face relative to all other emotions, whereas sad emotions generally inhibited visual speech information, particularly from the left side of the face. The results suggest that approach information may facilitate visual and auditory speech detection.     

Audiovisual speech from emotionally expressive and lateralized faces

Emotional expression and how it is lateralized across the two sides of the face may influence how we detect audiovisual speech. To investigate how these components interact we conducted experiments comparing the perception of sentences expressed with happy, sad, and neutral emotions. In addition we isolated the facial asymmetries for affective and speech processing by independently testing the two sides of a talker's face. These asymmetrical differences were exaggerated using dynamic facial chimeras in which left- or right-face halves were paired with their mirror image during speech production. Results suggest that there are facial asymmetries in audiovisual speech such that the right side of the face and right-facial chimeras supported better speech perception than their left-face counterparts. Affective information was also found to be critical in that happy expressions tended to improve speech performance on both sides of the face relative to all other emotions, whereas sad emotions generally inhibited visual speech information, particularly from the left side of the face. The results suggest that approach information may facilitate visual and auditory speech detection.     

Audiovisual integration increases the intentional step synchronization of side-by-side walkers

When people walk side-by-side, they often synchronize their steps. To achieve this, individuals might cross-modally match audiovisual signals from the movements of the partner and kinesthetic, cutaneous, visual and auditory signals from their own movements. Because signals from different sensory systems are processed with noise and asynchronously, the challenge of the CNS is to derive the best estimate based on this conflicting information. This is currently thought to be done by a mechanism operating as a Maximum Likelihood Estimator (MLE). The present work investigated whether audiovisual signals from the partner are integrated according to MLE in order to synchronize steps during walking. Three experiments were conducted in which the sensory cues from a walking partner were virtually simulated. In Experiment 1 seven participants were instructed to synchronize with human-sized Point Light Walkers and/or footstep sounds. Results revealed highest synchronization performance with auditory and audiovisual cues. This was quantified by the time to achieve synchronization and by synchronization variability. However, this auditory dominance effect might have been due to artifacts of the setup. Therefore, in Experiment 2 human-sized virtual mannequins were implemented. Also, audiovisual stimuli were rendered in real-time and thus were synchronous and co-localized. All four participants synchronized best with audiovisual cues. For three of the four participants results point toward their optimal integration consistent with the MLE model. Experiment 3 yielded performance decrements for all three participants when the cues were incongruent. Overall, these findings suggest that individuals might optimally integrate audiovisual cues to synchronize steps during side-by-side walking.     

不同目标标记方式对多目标追踪表现的影响

有关多目标追踪的研究多采用目标闪烁数次或目标周围出现方框等视觉方式对目标进行标记。在已有研究基础上,通过2个实验比较了不同目标数量下视觉平行标记、视觉序列标记、听觉序列标记(视听跨通道标记)和视听双通道序列标记4种目标标记方式对多目标追踪表现的影响。研究结果表明在多目标追踪任务中,线索阶段目标的视觉标记比视听跨通道标记更有效,且不受目标的序列标记或平行标记的影响,而视觉和听觉编码结合（视听双通道标记）可以促进任务难度较高时的追踪表现。     

视听整合加工及其神经机制

通常人们接收到来自不同感觉通道的信息时, 首先在大脑中各个分离的区域单独进行加工处理, 而后在多感官区进行整合。前人关于言语感知中视听整合加工的神经成像研究认为, 视觉和听觉信息能够相互影响; 两者进行整合的关键区域是人脑左后侧的颞上沟, 其整合效应受时间和空间因素的限制。未来的研究应致力于建立更加合理的实验范式和数据分析方法来探讨整合加工的脑区机制, 把多感官整合研究进一步延伸到更加复杂的领域。     

McGurk效应的影响因素与神经基础

McGurk效应(麦格克效应)是典型的视听整合现象, 该效应受到刺激的物理特征、注意分配、个体视听信息依赖程度、视听整合能力、语言文化差异的影响。引发McGurk效应的关键视觉信息主要来自说话者的嘴部区域。产生McGurk效应的认知过程包含早期的视听整合(与颞上皮层有关)以及晚期的视听不一致冲突(与额下皮层有关)。未来研究应关注面孔社会信息对McGurk效应的影响, McGurk效应中单通道信息加工与视听整合的关系, 结合计算模型探讨其认知神经机制等。