Voice responses to changes in pitch of voice or tone auditory feedback

By M. Sivasankar, J.J. Bauer, and C.R. Larson

It is well known that voice control depends both on volition and auditory feedback. This study tested the sensitivity of the audio-vocal control system to a subject’s own voice vs. an external source. This issue is important for understanding the degree to which the system may use internal (e.g., memory) vs. external (e.g. piano) sources of feedback for voice fundamental frequency control. Subjects vocalized a vowel at a constant F₀ while either hearing their voice and/or a tone feedback signal (500 Hz). Shifts in pitch (+/- 100 cents, 500 ms duration) of voice feedback or the tone elicited reflexive changes in voice F0. Responses to voice pitch-shifts were significantly larger than those to the tone (22 cents vs. 15 cents). There were no differences in response latency across the feedback conditions. The results indicate the system can respond to a variety of signals but responds best to the voice. The voice preference could be due to practice (developmental) or innate effects. An innate relationship implies the system is not amenable to modification, whereas the developmental explanation implies the system may be modified through use. Inappropriate behavioral modification of the feedback system could lead to some voice disorders such as exaggerated vocal tremor.