Indirect evidence of perturbation leads to changes in production of voice amplitude and fundamental frequency

Abstract

In this study, we explore the juncture of real-time feedback-based changes in speech production and those initiated by top-down knowledge of external factors such as audience characteristics or audience listening conditions. Twenty-four speakers were asked to solve interactive puzzles via remote auditory connection with an experimenter under five signal transmission conditions: normal/baseline, increased signal amplitude, decreased amplitude, + 100 cents shift in pitch, and −100 cents shift in pitch. Evidence of these changes was available to talkers only through the speech of the experimenter; no sidetone was introduced in the connection and listening conditions for talkers were otherwise normal. In response to hearing amplitude shifts in their partner’s speech, 19/24 talkers significantly altered their mean voice amplitude, while 6/24 altered f0 in response to shifted experimenter vocal pitch (RM-ANOVA, all corrected p’s < 0.05). Approximately 30% of responses countered the signal manipulation (e.g., f0 increase in response to low experimenter f0), while the remainder imitated the observed change. This combination of perturbation-like compensation and imitation/accommodation suggests that speakers can interpret transmission circumstances differently, or pursue different speech-related goals, during even very simple, constrained tasks.