The perceptual classification of speech and nonspeech sounds

Abstract

It is well known that the formant transition cues which signal the presence of [b] and [d] vary greatly according to vowel context [Liberman et al., Psychol. Rev. 74, 431–461 (1967)]. Yet, listeners nonetheless classify these different physical cues as belonging to the same phonetic segment. The present study focusses on the way in which adults are able to utilize formant transition information in perceptual classification tasks. Is there information in the formant transition that cues [b]'s and [d]'s in various vowel contexts which adults can use to form consistent groups in perceptual classification tasks? Do the perceptual groupings obtained conform to phonetic categories? Is formant transition information presented in a nonspeech context (as either two or three formant chirp patterns) grouped in the same way as when it occurs in the context of speech syllables? Our results suggest that (1) though classification according to phonetic categories is not subjects' preferred mode of grouping they can be instructed to classify in this way; (2) different groupings occur for the speech and nonspeech contexts; (3) there is sufficient information in three‐formant chirps to form groups based on phonetic categories. [Work supported by N.S.E.R.C. and NSF.]