Individual differences in speech and nonspeech processing among normal‐hearing subjects

Abstract

While a large portion of the variance among listeners in auditory speech processing is associated with the audibility of components of the speech waveform, it is not possible to predict individual differences in speech perception strictly from the audiogram. Psychoacoustic measures of spectral‐temporal acuity with nonspeech stimuli also have been shown to correlate only weakly (or not at all) with speech processing. In a replication and extension of an earlier study (Watson et al., J. Acoust. Soc. Am. Suppl. 1 71, S73) 100 normal‐hearing college students were tested on speech perception tasks (nonsense syllables, words, sentences in a noise background) and on 6 spectral‐temporal discrimination tasks using simple and complex nonspeech sounds. Factor analysis showed that the abilities that explain performance on the nonspeech tasks are quite distinct from those that account for performance on the four speech tasks. Performance was significantly correlated among speech tasks, and among nonspeech tasks. Either, (a) auditory spectral‐temporal acuity for nonspeech sounds is orthogonal to speech processing abilities, OR (b) we have yet to identify the appropriate task or types of nonspeech stimuli that exercise the abilities required for speech recognition. [Work supported grants from NIH and AFOSR to Indiana University.]