Abstract/Summary

Emotions can be communicated through multiple domains (e.g., human faces, face-like objects, speech prosody, and song) and processed at implicit (e.g., priming) or explicit (e.g., recognition) levels. Much research has been done on emotion processing in autism spectrum disorder (ASD), yet findings have been highly variable. It remains unresolved whether emotion processing ability at the two levels is generalised across domains or specific to certain domain(s) in ASD. While a number of correlates have been proposed to be associated with emotion processing (e.g., cognitive processing style, pitch perception, and alexithymic trait), their corresponding role in ASD has been infrequently explored. This thesis conducted a systematic review and meta-analysis on emotion recognition in ASD and examined whether explicit emotion recognition and implicit emotion priming differed between autistic neurotypical (NT) individuals across domains from a developmental perspective, while testing the contribution of several related correlates to these processes. Regarding the role of domain and processing level, the ASD group showed intact emotion priming and recognition accuracy but impaired recognition speed and efficiency across domains. These results suggest a generalised emotion ability across domains (i.e., no specific impairments for any particular domain), while indicating a dissociation between implicit and explicit emotion processing in ASD (i.e., impaired recognition speed and efficiency at the explicit level but spared priming at the implicit level). With regards to developmental changes, the developmental trajectory of implicit and explicit emotion processing appears largely comparable between the ASD and NT groups across domains, with age-related improvements seen for recognition and an age-related decline observed for priming. In terms of related correlates, the underlying processes of explicit emotion recognition appear to differ between autistic and NT individuals, with respect to the contribution of cognitive processing style and pitch perception. Additionally, the impaired recognition speed and efficiency in ASD could not be attributed to co-occurring alexithymia. These findings have shed light on the behavioural profile of emotion processing ability in ASD and the extent to which it differs from that in typical development, which has both theoretical and practical implications for emotion processing in ASD and typical development.