What we perceive is related to how we act. Nowhere is there a closer connection between action and perception than in speech and music. Communicating through speech or music involves executing planned actions and perceiving the consequences of those actions--the articulated sounds or the played music. We do not yet understand, however, the extent and nature of feedback's influence on fluency in communication. It is already clear that feedback is important: The hearing-impaired have difficulties in articulation, and singers have difficulties performing in large reverberant halls. On the other hand, some past findings suggest that fluent vocal production can occur when perceptual feedback is absent. Thus, role of perceptual feedback in the coordination of vocal action, and action in general, may be complex, and sensitive to the context in which it occurs.
With support from the National Science Foundation, Dr. Pfordresher will attempt to determine how perceptual feedback affects fluency in communication. To examine that fluency, Dr. Pfordresher will alter the feedback that follows an action. In a typical experimental task, a person produces a meaningful sequence of actions (e.g., playing a tune on the piano, singing a melody, or speaking a sentence), and the sounds that result from these actions are altered. For example, one might hear a note with the incorrect musical pitch after hitting a piano key, or hear the correct pitch for that key after a delay. The patterns of disruption caused by these alterations will be informative about how the brain relates actions to their consequences. The disruptions will be examined from several perspectives: behavioral measurements and brain imaging, investigations of both music and speech, and alterations of both auditory and visual feedback. It is hoped that the outcome of this research will a) improve our understanding of communication disorders that involve perceptual feedback (e.g., stuttering; b) reveal principles that help people interact more effectively with machines, where there can be large transmission delays, and c) reveal links between musical communication and linguistic communication.
