Speech perception deficits in poor readers: auditory processing or phonological coding?
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/-/fa/); (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.
Mody
M
M
Haskins Laboratories, New Haven, CT 06511, USA.
Studdert-Kennedy
M
M
Brady
S
S
D002648:Child; D006801:Humans; D007360:Intelligence; D010468:Perceptual Disorders / Q000175:diagnosis*; D010700:Phonetics; D011932:Reading; D013063:Speech Discrimination Tests; D013067:Speech Perception; D013997:Time Factors