Neural dynamics of induced vocal tract vibrations during vocal emotion recognition

Emotional prosody is defined as suprasegmental and segmental changes in voice and related acoustic parameters that can inform the listener about the emotional state of the speaker. Despite a large corpus of literature in psychological and brain mechanisms in emotional prosody perception, the perspective of embodied cognition in these mechanisms have been largely neglected. Here we investigated the influence of induced bodily vibrations in the categorization of ambiguous emotional vocalizations in an event-related potential study ( N =24). The factorial design included Vocal emotion [anger and fear] and external Vibration [anger, fear, and none] as fixed factors. Emotional voices were morphed between a fearful expression with the speaker’s identity-matching angry expression, creating blends of emotions in each voice. Emotional congruent and incongruent vibrations were delivered on the skin through transducers placed close to the vocal cords. We hypothesized that induced bodily vibrations would constitute an interoceptive and proprioceptive feedbacks that would influence the perception of emotions, especially for more ambiguous voices as ambiguity would favour the processing of other available sensory information, here toward the tactile sensory modality. Behavioural results revealed that induced vibrations skewed the participants’ emotional ratings by biasing responses congruent with the vibration. Event-related potentials results indicated that N100 and P200 components subtending the early processing of emotional prosody were significantly modulated by induced vibrations in the congruent setting, which could be considered as a facilitation effect for emotion recognition at early stage of processing. A significant modulation of the late positive component was also observed in the incongruent setting, suggesting an error processing mechanism. EEG source reconstruction highlighted significant contrasts between vibration types in prefrontal, motor, somatosensory, and insular cortices. Altogether, our results suggest that voice-associated vibrations would play a significant role in vocal emotion perception and recognition through embodied mechanisms at both behavioral and neural levels.