This dissertation research sought to determine in what ways, and in what contexts, emotional facial expressions are atypical in the Autism Spectrum Disorder (ASD) population, and to investigate the specific role that alexithymia—a condition characterized by difficulties identifying and describing one’s feelings—may relate to facial expression production abilities in individuals with and without ASD. Results of a meta-analysis showed that on average, individuals with ASD display facial expressions less frequently and are less likely to share facial expressions with others in naturalistic settings or automatically mimic the expressions of real faces or face stimuli in comparison to non-ASD comparison groups. Their facial expressions are rated as more awkward or unusual in appearance, sometimes making it difficult for observers to identify what emotion is being expressed. However, across studies, participants with ASD do not express emotions less intensely, nor do they respond more slowly to emotion-eliciting stimuli. Age, intellectual functioning of ASD participants, and methodological features of the study, significantly moderated the strength of effect sizes. A second study examined spontaneous facial production in response to emotionally arousing videos in children with and without ASD. Results showed that alexithymia, but not ASD traits, was negatively correlated with spontaneous production of negative facial expressions. A similar pattern of results was found in a third study, such that alexithymia and depression were associated with less spontaneous emotional expression during tasks that required typically developing undergraduates to watch emotional video clips or tell emotional stories about their personal lives. In a separate task in which participants were instructed to pose emotional facial expressions, it was hypothesized that reduced voluntary expression accuracy would be more strongly related to ASD traits than alexithymia or depression, although support for this prediction was mixed. Results provide partial support for the suggestion that reduced spontaneous expression and reduced voluntary expression accuracy have distinct correlates. I argue that the alexithymia construct deserves significantly more research and clinical attention within the ASD population.
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Thesis advisor: Birmingham, Elina
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