Perceptual compensation in individuals with autism spectrum disorders

Langston, Elizabeth A. M.S., Purdue University, August 2014. Perceptual Compensation in Individuals with Autism Spectrum Disorders. Major Professor: Amanda Seidl. Compensation for coarticulation is the extent in which an individual perceives the contextual variations of speech. When presented with an ambiguous consonant-vowel segment (e.g., a consonant halfway between /sa/ and /ʃa/) research illustrates that a listener is likely to compensate for coarticulation with the following vowel. Therefore, a listener will be more likely to report an ambiguous speech sound as /s/ when it occurs before [u] than before [a]. Previous results have suggested that, within neurotypical individuals, the degree to which individuals compensate for coarticulation may be related to their Autism Quotient (AQ; Yu, 2010). However, this research did not examine individuals with an autism spectrum disorder (ASD). The current study extends this research by exploring compensation for coarticulation in individuals with an ASD as compared to neurotypical peers in a phoneme classification task (labeling an ambiguous phoneme as either /s/ or /ʃ/). Results from a generalized linear mixed effect model suggest that while there are no differences in how the clinical and neurotypical population compensate for coarticulation, there is a difference in how these two cohorts categorize phonemes. Individuals with an ASD illustrate a gradient categorization slope, while neurotypical individuals show a categorical response curve.