Atypical context-dependent speech processing in autism

Abstract

The ability to take contextual information into account is essential for successful speech processing. This study examines individuals with high-functioning autism and those without in terms of how they adjust their perceptual expectation while discriminating speech sounds in different phonological contexts. Listeners were asked to discriminate pairs of sibilant-vowel monosyllables. Typically, discriminability of sibilants increases when the sibilants are embedded in perceptually enhancing contexts (if the appropriate context-specific perceptual adjustment were performed) and decreases in perceptually diminishing contexts. This study found a reduction in the differences in perceptual response across enhancing and diminishing contexts among high-functioning autistic individuals relative to the neurotypical controls. The reduction in perceptual expectation adjustment is consistent with an increase in autonomy in low-level perceptual processing in autism and a reduction in the influence of top-down information from surrounding information.