Are you sure it’s your voice? Exploring the relations between phonetic alignment and sense of agency

When speakers interact, their behavior tends to converge as they try to anticipate each other's actions. Speakers also predict the outcomes of their own behaviors. However, studies on auditory feedback (i.e., self-generated voice) during speech production show that mismatches between the sensory signal and expected outcomes of speech motor commands trigger a compensatory response, rather than a converging response. These observations imply that speakers adjust their production based on their sense of agency of the input signal. In this study, we investigated whether a constant mismatch between the perceived and expected pitch of a speaker's voice could alter their sense of agency on their self-generated voice. In an experiment, participants were asked to read sentences with a delayed self-generated voice while part of the participants’ voice was shifted higher or lower. The results show that most participants whose voice was shifted aligned their pitch to their pitch-shifted voice and lengthened their accented vowels less in response to the delay than the participants whose voice was not shifted. These findings suggest that pitch alignment to unexpected self-generated signals indicates a reduction of speakers' sense of agency on their voice, making them less perturbed by the delay of their auditory feedback.