Adaptation to frequency-shifted auditory feedback

Abstract

Subjects attempted to whistle at the frequency of a target note when the sound of their own whistling, fed back through headphones, was either electronically shifted in frequency or blotted out by intense masking noise. With auditory feedback masked out, they could still hit a note to within .5-2 semitones, so proprioception from lips and tongue must be internally calibrated to about this accuracy, in the absence of auditory feedback. When the frequency of their whistling was electronically shifted by plus or minus 300 Hz, they adjusted the frequency they produced, shifting it down or up just enough to hold constant the frequency feedback to their ears. Thus, auditory feedback is used to fine-tune the motor output, and overrides it when a cue conflict is experimentally introduced. When the electronic frequency shift was gradually increased from zero to ±300 Hz, subjects adapted to the shift, and when they subsequently tried to hit a target note with auditory feedback masked off, they showed a negative aftereffect of 50%-60%, making frequency errors of about ±150-180 Hz. Finally, after adapting to a shift of ±250 Hz, subjects attempted to reset the electronic frequency shift to subjective zero and again showed aftereffects of 45%-77%. Proprioceptive and auditory feedback information in controlling whistling can be compared with proprioceptive and visual feedback in controlling limb position. © 1979 Psychonomic Society, Inc.