Perceiving a Stranger's Voice as Being One's Own: A ‘Rubber Voice’ Illusion?

We describe an illusion in which a stranger's voice, when presented as the auditory concomitant of a participant's own speech, is perceived as a modified version of their own voice. When the congruence between utterance and feedback breaks down, the illusion is also broken. Compared to a baseline condition in which participants heard their own voice as feedback, hearing a stranger's voice induced robust changes in the fundamental frequency (F0) of their production. Moreover, the shift in F0 appears to be feedback dependent, since shift patterns depended reliably on the relationship between the participant's own F0 and the stranger-voice F0. The shift in F0 was evident both when the illusion was present and after it was broken, suggesting that auditory feedback from production may be used separately for self-recognition and for vocal motor control. Our findings indicate that self-recognition of voices, like other body attributes, is malleable and context dependent

Auditory, Visual, and Audiovisual Speech Intelligibility for Sentence-Length Stimuli: An Investigation of Conversational and Clear Speech

Previous investigators have shown that the use of clear speech improves the auditory speech intelligibility of talkers. In the present study, the differences in speech intelligibility for sentences spoken conversationally and in a clear manner were investigated under three different experimental conditions: Auditory-only, visual-only, and audiovisually. Six talkers were videotaped while saying a list of 17 sentences twice: first while using conversational speech and then while using clear speech. The recorded stimuli were randomized and presented to subjects under one of the three experimental conditions, A broadband noise was mixed with the audio signal for the auditory-only and the audiovisual conditions. An auditory, visual, and audiovisual speech intelligibility score was obtained for the tokens of conversational and clear speech spoken by individual talkers. Overall, in each experimental condition, speech intelligibility improved significantly for the tokens of clear speech. However, for the auditory-only and the visual-only conditions there was a significant interaction between talker and manner of speech. In those sensory modalities, the speech intelligibility of some talkers improved when they used clear speech. The results suggest that for an individual talker there is not a direct association in the amount of improvement provided by the use of clear speech across sensory modalities

Multivoxel Patterns Reveal Functionally Differentiated Networks Underlying Auditory Feedback Processing of Speech

Contains fulltext : 122909.pdf (publisher's version ) (Open Access)The everyday act of speaking involves the complex processes of speech motor control. An important component of control is monitoring, detection, and processing of errors when auditory feedback does not correspond to the intended motor gesture. Here we show, using fMRI and converging operations within a multivoxel pattern analysis framework, that this sensorimotor process is supported by functionally differentiated brain networks. During scanning, a real-time speech-tracking system was used to deliver two acoustically different types of distorted auditory feedback or unaltered feedback while human participants were vocalizing monosyllabic words, and to present the same auditory stimuli while participants were passively listening. Whole-brain analysis of neural-pattern similarity revealed three functional networks that were differentially sensitive to distorted auditory feedback during vocalization, compared with during passive listening. One network of regions appears to encode an "error signal" regardless of acoustic features of the error: this network, including right angular gyrus, right supplementary motor area, and bilateral cerebellum, yielded consistent neural patterns across acoustically different, distorted feedback types, only during articulation (not during passive listening). In contrast, a frontotemporal network appears sensitive to the speech features of auditory stimuli during passive listening; this preference for speech features was diminished when the same stimuli were presented as auditory concomitants of vocalization. A third network, showing a distinct functional pattern from the other two, appears to capture aspects of both neural response profiles. Together, our findings suggest that auditory feedback processing during speech motor control may rely on multiple, interactive, functionally differentiated neural systems

A face-to-muscle inversion of a biomechanical face model for audiovisual and motor control research

Colloque avec actes et comité de lecture. internationale.International audienceMuscle-based models of the human face produce high quality animation but rely on recorded muscle activity signals or synthetic muscle signals often derived by trial and error. In this paper we present a dynamic inversion of a muscle-based model that permits the animation to be created from kinematic recordings of facial movements. Using a nonlinear optimizer (Powell's algorithm) the inversion produces a muscle activity set for 16 muscle groups in the lower face that minimize the root mean square error between kinematic data recorded with OPTOTRAK and the corresponding nodes of the modeled facial mesh. This inverted muscle activity is then used to animate the facial model. The results of a first experiment showed that the inversion-synthesis method can accurately reproduce a synthetic facial animation, even for a partial sampling of the face. The results of a second experiment showed that the method is as successful for OPTOTRAK recording of a talker uttering a sentence. The animation was of high quality

Perturbing the consistency of auditory feedback in speech

Sensory information, including auditory feedback, is used by talkers to maintain fluent speech articulation. Current models of speech motor control posit that speakers continually adjust their motor commands based on discrepancies between the sensory predictions made by a forward model and the sensory consequences of their speech movements. Here, in two within-subject design experiments, we used a real-time formant manipulation system to explore how reliant speech articulation is on the accuracy or predictability of auditory feedback information. This involved introducing random formant perturbations during vowel production that varied systematically in their spatial location in formant space (Experiment 1) and temporal consistency (Experiment 2). Our results indicate that, on average, speakers’ responses to auditory feedback manipulations varied based on the relevance and degree of the error that was introduced in the various feedback conditions. In Experiment 1, speakers’ average production was not reliably influenced by random perturbations that were introduced every utterance to the first (F1) and second (F2) formants in various locations of formant space that had an overall average of 0 Hz. However, when perturbations were applied that had a mean of +100 Hz in F1 and −125 Hz in F2, speakers demonstrated reliable compensatory responses that reflected the average magnitude of the applied perturbations. In Experiment 2, speakers did not significantly compensate for perturbations of varying magnitudes that were held constant for one and three trials at a time. Speakers’ average productions did, however, significantly deviate from a control condition when perturbations were held constant for six trials. Within the context of these conditions, our findings provide evidence that the control of speech movements is, at least in part, dependent upon the reliability and stability of the sensory information that it receives over time