Stabilizing variability in the auditory feedback of speech

Abstract

Auditory feedback is an essential part of speech motor control and speech learning. When feedback is perturbed in laboratory settings (e.g., Houde and Jourdan, 1998), speakers, on average, compensate for the perceived error. There is, however, considerable individual variability observed in natural speech and in speakers’ responses to auditory feedback manipulations (e.g., Purcell and Munhall, 2006). Here, we introduce a novel manipulation that stabilized the predictability of auditory feedback of 20 female speakers. Participants produced the English word “head” 95 times in two different conditions. In the Control condition, subjects produced all utterances with unaltered auditory feedback. In the Stabilization condition, subjects were presented with a recording of one of their own utterances of “head” synchronized with their speech on some trials. Auditory feedback was thus made constant by playing the same recording for a set of 30 trials. Trial-to-trial variability of the talkers’ speech did not change as a result of this constant feedback. Time-series analyses were performed to examine whether production variability differed among speakers in the two conditions. Results will be discussed regarding the possible role of variability in speech motor control and the importance of developing methods to detect state-change in individual time-series data.