AUTOMATICITY IN SPEECH-PERCEPTION - SOME SPEECH NONSPEECH COMPARISONS/

Three experiments used sine-wave replicas of speech sounds to explore some differences between speech perception and general auditory percep tion. The experiments compared patterns of behavior in categorization and discrimination tasks for listeners reporting either speech or nons peech percepts of sine-wave replicas of speech. We hypothesized that t he perception of speech sounds is automatized, while the perception of less familiar sounds is not. The first experiment was designed to inv estigate the perception of relatively long initial consonant transitio ns using a synthetic /wa/-/ya/ sine-wave analog continuum. Speech list eners perceived the continuum categorically, but nonspeech listeners c ould not consistently categorize the items in the continuum. In the se cond experiment, both speech and nonspeech listeners could consistentl y categorize stimuli having final glides (an /ay/-/aw/ sine-wave repli ca continuum), but differences between speech and nonspeech listeners were found in the slopes of the identification functions, in reaction times, and in the effect of context. These differences are consistent with the hypothesis that speech perception is automatized. In the thir d experiment, nonspeech listeners' discrimination sensitivity was grea ter than speech listeners'. The observed pattern of results suggests t hat speech perception is accomplished by a fast, obligatory, and thus automatic perceptual mechanism.