Abstract/Summary

Autistic individuals may possess enhanced auditory abilities, but their language profiles are highly heterogeneous. Such inconsistent results, to a certain extent, can be explained by not controlling for confounding variables (e.g., cognitive abilities), and by not using closely matched stimuli across domains. The current thesis comprised three main aims: (1) to investigate whether autistic individuals will show superior performance at the tone and intonation perception in a foreign tone language compared to controls; (2) to explore the differences in groups’ comprehension abilities whilst recalling sentences in different conditions (e.g., spoken vs sung sentences); and (3) to investigate autistic individuals’ expectancy on both perceptual and production tasks using closely matched linguistic and melodic stimuli. In Study 1, no group differences were found on any Mandarin tone or intonation discrimination task, and we did not identify a subgroup of autistic individuals with superior perceptual abilities. Study 2 preliminary findings showed no group differences when recalling sentences, whereas the results from an online study showed impaired sentence recall in the autism group compared to controls. In Study 3 autistic individuals produced more ‘the most frequent’ responses on the melody completion task in the high expectancy but not in the low expectancy condition, compared to controls. Both groups performed equally well on the sentence completion task across conditions, whereas overall, autistic participants produced more NA responses than controls. However, none of these differences reached significance after applying the Bonferroni correction. The groups did not differ in their ratings across the tasks (sentences/melodies) or the conditions (high/low expectancy) and did not differ in their RTs across the tasks/conditions. The findings of this thesis provide evidence of either intact or enhanced auditory processing and either intact or impaired speech processing in autism. Future studies are warranted to further explore the underlying processes of production and perception processing in autism.