Neural dynamics of induced vocal tract vibrations during vocal emotion recognition
Despite a large corpus of literature in psychological and brain mechanisms on emotional prosody perception, the perspective of embodied cognition in these mechanisms have been largely neglected. Here we investigated the influence of induced bodily vibrations on the categorization of ambiguous emotional vocalizations using event-related potentials (ERPs). Emotional voices were morphed between a fearful expression with the speakers identity-matching angry expression, creating blends of emotions in each voice. Emotional congruent and incongruent vibrations were delivered on the skin close to the vocal cords. Congruent with our hypotheses, behavioural results revealed that induced vibrations skewed the participants emotional ratings by biasing responses towards the vibrations emotion. ERPs indicated that N100 and P200 components subtending the early processing of emotional prosody were significantly modulated by induced vibrations in the congruent setting, considered as a facilitation effect for emotion recognition at early stages of processing. A modulation of the late positive component was also observed in the incongruent setting, suggesting an error processing mechanism. Source reconstruction highlighted effects of vibration types in prefrontal, motor, somatosensory, and insular cortices. Our results suggest that voice-associated vibrations may play a significant role in vocal emotion processing and recognition through an embodied mechanism.