This paper looks into how preteens with autism (Asperger, PDD-NOS) compare to healthy controls (matched in terms of age, IQ and educational level) in the way they interpret audiovisual expressions produced by adult or child speakers. In previous research, we had recorded utterances from those groups of speakers as they were responding to easy and difficult questions in a quiz-like experiment, so that they were not always equally confident about the correctness of a given answer. The task given to the preteens in the current study was to judge how certain a speaker appeared in his/her response to a question, where they could base such judgments both on auditory and visual properties of the speakers. Results reveal that all groups of preteens are able to estimate a speaker's confidence level on the basis of audiovisual properties, albeit that the preteens diagnosed with PDD-NOS performed significantly worse at this than the other two groups. Moreover, in line with previous results, participants found the data coming from child speakers harder to judge than those produced by adult speakers.

Index Terms: nonverbal communication, prosody, cues to speaker confidence, autism