Speech Perception Deficits in Poor Readers: Auditory Processing or Phonological Coding?

Abstract

Poor readers are inferior to normal-reading peers in aspects of speech perception. Two hypotheses have been proposed to account for their deficits: (i) a speech-specific failure in phonological representation and (ii) a general deficit in auditory “temporal processing,” such that they cannot easily perceive the rapid spectral changes of formant transitions at the onset of stop-vowel syllables. To test these hypotheses, two groups of second-grade children (20 “good readers,” 20 “poor readers”), matched for age and intelligence, were selected to differ significantly on a /ba/–/da/ temporal order judgment (TOJ) task, said to be diagnostic of a temporal processing deficit. Three experiments then showed that the groups did not differ in: (i) TOJ when /ba/ and /da/ were paired with more easily discriminated syllables (/ba/–/sa/, /da/–/∳a/); (ii) discriminating nonspeech sine wave analogs of the second and third formants of /ba/ and /da/; (iii) sensitivity to brief transitional cues varying along a synthetic speech continuum. Thus, poor readers’ difficulties with /ba/–/da/ reflected perceptual confusion between phonetically similar, though phonologically contrastive, syllables rather than difficulty in perceiving rapid spectral changes. The results are consistent with a speech-specific, not a general auditory, deficit.