Delay detectability and speech rate as a function of delay duration in auditory feedback.

Abstract

The relationship between delayed auditory feedback and speech rate, speech error rate, and delay detectability was examined as a function of delay duration. Thirty adult participants read paragraphs while listening to delayed feedback at 10 logarithmically spaced delay durations between 0 and 180 ms. Significant main effects of delay duration was found for speech rate as well as number of disfluencies. In addition, there was a significant effect of delay duration on the detectability of the delay as well as on reaction times even for very short delays (i.e., 16 ms). For reasons that are currently unknown, delays at 45 ms were significantly more difficult to detect than delays of either 32 or 64 ms. This was evident for both reaction-time data as well as signal-detection data. There was a linear, downward trend in speech rate for delays of 32 ms and longer, with a small deviation at 45 ms. Disfluencies were infrequent but there were significant increases in stuttering-like disruptions at longer delays (i.e., 128–180 ms). [Work supported by SSHRC.]