Reading disability: A deficit in the processing of rapid spectral changes or in phonological coding?

Abstract

Reading‐impaired children have been said to suffer from an auditory deficit, indexed by difficulties in processing formant transitions [P. Tallal, Brain & Lang. 9, 182–198 (1980)]. Having established that poor readers (n=20) made significantly more errors than good readers (n=20) on discrimination between stop‐vowel syllables, contrasting in initial F2 and F3 transitions (/ba/ and /da/), but not between nonspeech sinewave analogs of F2 and F3, the present study compared the same groups on identification of (i) a /sei‐stei/ synthetic continuum, where F1 transition cued the contrast, and (ii) two hybrid /su–sh/ continua, each icative series by the formant transitions of naturally spoken vowels. Poor readers did not differ from good readers in phoneme boundaries, but did exhibit shallower identification functions, significantly so on the fricative continua. The results do not support the hypothesized auditory deficit: Less consistent discrimination or identification by poor readers on speech tasks but not on the nonspeech control task, suggests phonological rather than auditory difficulties.