Autistic Listeners Demonstrate Robust Lexically Guided Perceptual Learning.

Listeners accommodate rampant variability in speech input, at least in part, by adapting to structured phonetic variation. However, most work demonstrating this type of perceptual learning has focused on group-level effects in modal populations. This approach masks potentially meaningful differences-present among all listeners but particularly associated with autism-in sensory perception, social functioning, and language processing. These differences may be expected to influence adaptation, but their roles remain unclear. The present investigation aimed to clarify the relationships between autism, perceptual acuity, and adaptation. Listeners (n = 80, of which 40 were diagnosed with autism) were exposed to spectral energy ambiguous between /s/ and /ʃ/ in lexical contexts designed to elicit adaptation. Learning was assessed by comparing categorization of an ashi-asi test continuum before and after the critical lexically guided exposure. Autistic traits and pitch pattern sensitivity were also assessed. Robust learning was observed by both the general population and autistic listeners, with no evidence to suggest that learning was associated with autistic traits or pitch pattern sensitivity. These results advance theories of speech adaptation by constraining determinants of lexically guided perceptual learning to suggest that the social language traits of autism may be orthogonal to adaptation in speech perception.