Correlations between voice F0 responses and manual reaction times to auditory feedback pitch shifts

Abstract

There appear to be two types of voice F0 responses to voice auditory feedback pitch manipulations: early, opposing responses, and later responses that vary across subject and task. The purpose of this study was to determine whether either type correlates with volitional motor abilities. Subjects vocalized /u/ into a microphone while listening to their voice fed back over headphones. Subjects also pressed a joystick button as rapidly as possible upon hearing any experimenter‐generated auditory feedback pitch shift. Pitch shift stimuli were 50 cents upward or downward (randomized), and 100‐ms duration. Voice was recorded, F0 extracted, smoothed, time aligned to the onset of the shift, averaged according to shift direction, and the onset of the first voice F0 response was measured. Average manual reaction time was calculated. Findings indicated no significant correlation between manual responses and early voice F0 response. However, later voice F0 responses and manual reaction times were positively correlated. These results are consistent with the hypothesis that the early voice F0 response is automatically generated, and later responses are under voluntary influence. Results also suggest that the variability of later voice F0 responses may be a function of individual differences in volitional motor response abilities. [Work supported by NINDS.]