A Consideration of Stimulus Length in Developmental Studies of Delayed Auditory Feedback

Abstract

One of the methodological problems encountered in developmental studies of delayed auditory feedback (DAF) is that speakers of different ages have different rates of speech under normal auditory feedback conditions, which affect speech under DAF. That is, if a speaker can speak fast enough under certain conditions of DAF, he can complete the stimulus phrase before the DAF has returned to his ears (or substantially affected his speech). These differences in speech rate would seem to favor age groups whose speakers have faster rates of speech (older speakers) rather than age groups whose speakers have slower rates of speech (younger speakers). Consequently, fixed-length stimulus phrases read under DAF present varying degrees of difficulty depending on how rapidly the speaker can complete the stimulus. The present paper evaluates the use of the differential-length appending clause as a technique to equalize these differences in speech rates of various age groups, originally used by MacKay [D. G. MacKay, J. Acoust. Soc. Amer. 43, 811–821 (1968)], and suggests the design for a study that would help determine the effects of the differential-length appending clause upon speech under DAF.