15 research outputs found

    Lexical and audiovisual bases of perceptual adaptation in speech

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    Audiovisual and lexical cues do not additively enhance perceptual adaptation

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    When listeners experience difficulty in understanding a speaker, lexical and audiovisual (or lip-reading) information can be a helpful source of guidance. These two types of information embedded in speech can also guide perceptual adjustment, also known as recalibration or perceptual retuning. With retuning or recalibration, listeners can use these contextual cues to temporarily or permanently reconfigure internal representations of phoneme categories to adjust to and understand novel interlocutors more easily. These two types of perceptual learning, previously investigated in large part separately, are highly similar in allowing listeners to use speech-external information to make phoneme boundary adjustments. This study explored whether the two sources may work in conjunction to induce adaptation, thus emulating real life, in which listeners are indeed likely to encounter both types of cue together. Listeners who received combined audiovisual and lexical cues showed perceptual learning effects similar to listeners who only received audiovisual cues, while listeners who received only lexical cues showed weaker effects compared to the two other groups. The combination of cues did not lead to additive retuning or recalibration effects, however, suggesting that lexical and audiovisual cues operate differently with regard to how listeners utilize them for reshaping perceptual categories. Reaction times did not significantly differ across the three conditions, so none of the forms of adjustment were either aided or hindered by processing time differences. Mechanisms underlying these forms of perceptual learning may diverge in numerous ways despite similarities in experimental applications

    Audiovisual and lexical cues do not additively enhance perceptual adaptation

    No full text
    When listeners experience difficulty in understanding a speaker, lexical and audiovisual (or lip-reading) information can be a helpful source of guidance. These two types of information embedded in speech can also guide perceptual adjustment, also known as recalibration or perceptual retuning. With retuning or recalibration, listeners can use these contextual cues to temporarily or permanently reconfigure internal representations of phoneme categories to adjust to and understand novel interlocutors more easily. These two types of perceptual learning, previously investigated in large part separately, are highly similar in allowing listeners to use speech-external information to make phoneme boundary adjustments. This study explored whether the two sources may work in conjunction to induce adaptation, thus emulating real life, in which listeners are indeed likely to encounter both types of cue together. Listeners who received combined audiovisual and lexical cues showed perceptual learning effects similar to listeners who only received audiovisual cues, while listeners who received only lexical cues showed weaker effects compared to the two other groups. The combination of cues did not lead to additive retuning or recalibration effects, however, suggesting that lexical and audiovisual cues operate differently with regard to how listeners utilize them for reshaping perceptual categories. Reaction times did not significantly differ across the three conditions, so none of the forms of adjustment were either aided or hindered by processing time differences. Mechanisms underlying these forms of perceptual learning may diverge in numerous ways despite similarities in experimental applications

    Audiovisual and lexical cues do not additively enhance perceptual adaptation

    No full text
    When listeners experience difficulty in understanding a speaker, lexical and audiovisual (or lipreading) information can be a helpful source of guidance. These two types of information embedded in speech can also guide perceptual adjustment, also known as recalibration or perceptual retuning. With retuning or recalibration, listeners can use these contextual cues to temporarily or permanently reconfigure internal representations of phoneme categories to adjust to and understand novel interlocutors more easily. These two types of perceptual learning, previously investigated in large part separately, are highly similar in allowing listeners to use speech-external information to make phoneme boundary adjustments. This study explored whether the two sources may work in conjunction to induce adaptation, thus emulating real life, in which listeners are indeed likely to encounter both types of cue together. Listeners who received combined audiovisual and lexical cues showed perceptual learning effects similar to listeners who only received audiovisual cues, while listeners who received only lexical cues showed weaker effects compared with the two other groups. The combination of cues did not lead to additive retuning or recalibration effects, suggesting that lexical and audiovisual cues operate differently with regard to how listeners use them for reshaping perceptual categories. Reaction times did not significantly differ across the three conditions, so none of the forms of adjustment were either aided or hindered by processing time differences. Mechanisms underlying these forms of perceptual learning may diverge in numerous ways despite similarities in experimental application

    Audiovisual and lexical cues do not additively enhance perceptual adaptation

    Get PDF
    When listeners experience difficulty in understanding a speaker, lexical and audiovisual (or lipreading) information can be a helpful source of guidance. These two types of information embedded in speech can also guide perceptual adjustment, also known as recalibration or perceptual retuning. With retuning or recalibration, listeners can use these contextual cues to temporarily or permanently reconfigure internal representations of phoneme categories to adjust to and understand novel interlocutors more easily. These two types of perceptual learning, previously investigated in large part separately, are highly similar in allowing listeners to use speech-external information to make phoneme boundary adjustments. This study explored whether the two sources may work in conjunction to induce adaptation, thus emulating real life, in which listeners are indeed likely to encounter both types of cue together. Listeners who received combined audiovisual and lexical cues showed perceptual learning effects similar to listeners who only received audiovisual cues, while listeners who received only lexical cues showed weaker effects compared with the two other groups. The combination of cues did not lead to additive retuning or recalibration effects, suggesting that lexical and audiovisual cues operate differently with regard to how listeners use them for reshaping perceptual categories. Reaction times did not significantly differ across the three conditions, so none of the forms of adjustment were either aided or hindered by processing time differences. Mechanisms underlying these forms of perceptual learning may diverge in numerous ways despite similarities in experimental applications

    Adaptive Plasticity in Perceiving Speech Sounds

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    Interleaved lexical and audiovisual information can retune phoneme boundaries

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    To adapt to situations in which speech perception is difficult, listeners can apply perceptual learning to adjust boundaries between phoneme categories. Such adjustment can draw on contextual, including lexical, information in surrounding speech, or on visual cues via speech- reading. In the present study, listeners proved able to flexibly adjust the boundary between two plosive/stop consonants, /p/-/t/, using both lexical and speech-reading information and given the same experimental design for both cue types. Videos of a speaker pronouncing pseudo-words, and audio recordings of Dutch words, were presented in alternating blocks of either stimulus type, and listeners were able to switch between cues to recalibrate, with effect sizes comparable to results from listeners receiving only a single source of information. Overall, audiovisual cues (i.e., the videos) produced the stronger after-effects, commensurate with their environmental applicability. Lexical cues were nonetheless able to induce retuning effects, despite fewer exposure stimuli and a changing phoneme bias, and despite a design unlike most previous studies of lexically-guided retuning and more typical of audiovisual recalibration studies. Participants who received only audiovisual exposure also showed recalibration effects comparable to previous studies, while a lexical-only group showed lower levels of retuning effects. The presence of the lexical retuning effects nonetheless suggests that lexically-based retuning may be invoked at a faster rate than previously seen. In general, this technique has further illuminated the robustness of adaptability in speech perception, and offers the potential to enable further comparisons across differing forms of perceptual learning

    Interleaved lexical and audiovisual information can retune phoneme boundaries

    No full text
    To adapt to situations in which speech perception is difficult, listeners can apply perceptual learning to adjust boundaries between phoneme categories. Such adjustment can draw on contextual, including lexical, information in surrounding speech, or on visual cues via speech- reading. In the present study, listeners proved able to flexibly adjust the boundary between two plosive/stop consonants, /p/-/t/, using both lexical and speech-reading information and given the same experimental design for both cue types. Videos of a speaker pronouncing pseudo-words, and audio recordings of Dutch words, were presented in alternating blocks of either stimulus type, and listeners were able to switch between cues to recalibrate, with effect sizes comparable to results from listeners receiving only a single source of information. Overall, audiovisual cues (i.e., the videos) produced the stronger after-effects, commensurate with their environmental applicability. Lexical cues were nonetheless able to induce retuning effects, despite fewer exposure stimuli and a changing phoneme bias, and despite a design unlike most previous studies of lexically-guided retuning and more typical of audiovisual recalibration studies. Participants who received only audiovisual exposure also showed recalibration effects comparable to previous studies, while a lexical-only group showed lower levels of retuning effects. The presence of the lexical retuning effects nonetheless suggests that lexically-based retuning may be invoked at a faster rate than previously seen. In general, this technique has further illuminated the robustness of adaptability in speech perception, and offers the potential to enable further comparisons across differing forms of perceptual learning

    Lexical and lip-reading information as sources of phonemic boundary recalibration

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    Listeners can flexibly adjust boundaries between phonemes when exposed to biased information. Ambiguous sounds are particularly susceptible to being interpreted as certain phonemes depending on the surrounding context, so that if they are embedded into words, the sound can be perceived as the phoneme that would naturally occur in the word. Similarly, ambiguous sounds presented simultaneously with videos of a speaker’s lip movements can also affect the listener’s perception, where the ambiguous sound can be interpreted as the phoneme corresponding with the lip movements of the speaker

    Neural Correlates of Phonetic Adaptation as Induced by Lexical and Audiovisual Context

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    When speech perception is difficult, one way listeners adjust is by reconfiguring phoneme category boundaries, drawing on contextual information. Both lexical knowledge and lip-reading cues are used in this way, but it remains unknown whether these two differing forms of perceptual learning are similar at a neural level. This study compared phoneme boundary adjustments driven by lexical or audiovisual cues, using ultra-high-field 7-T fMRI. During imaging, participants heard exposure stimuli and test stimuli. Exposure stimuli for lexical retuning were audio recordings of words, and those for audiovisual recalibration were audio–video recordings of lip movements during utterances of pseudo words. Test stimuli were ambiguous phonetic strings presented without context, and listeners reported what phoneme they heard. Reports reflected phoneme biases in preceding exposure blocks (e.g., more reported /p/ after /p/-biased exposure). Analysis of corresponding brain responses indicated that both forms of cue use were associated with a network of activity across the temporal cortex, plus parietal, insula, and motor areas. Audiovisual recalibration also elicited significant occipital cortex activity despite the lack of visual stimuli. Activity levels in several ROIs also covered with strength of audiovisual recalibration, with greater activity accompanying larger recalibration shifts. Similar activation patterns appeared for lexical retuning, but here, no significant ROIs were identified. Audiovisual and lexical forms of perceptual learning thus induce largely similar brain response patterns. However, audiovisual recalibration involves additional visual cortex contributions, suggesting that previously acquired visual information (on lip movements) is retrieved and deployed to disambiguate auditory perception
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