Holdsworth, Imogen2024-06-072024-06-072022https://hdl.handle.net/2440/141170This item is only available electronically.Children's knowledge of emotional facial expressions develops slowly with age. Resultantly, when interacting with very young children, others often perform infant-directed modifications, simplifying and exaggerating their actions. However, the attainment of emotional knowledge, including from facial expressions, follows an alternate trajectory in Autism Spectrum Disorder (ASD). Despite symptoms of ASD often appearing in early childhood, it is unknown whether others adapt their emotional facial expressions differently for atypically versus typically developing children. The present study analyses the emotional facial expressions appearing in the SAYCam video corpus, a naturalistic, longitudinal dataset of infant-perspective films from one autistic and two typically developing children. Specifically, the intensity and complexity of these expressions is investigated. Facial expression analysis software identified the expressions of surprise and fear were particularly exaggerated, while joyful expressions were significantly less intense, for the autistic relative to the typically developing children. Furthermore, the direction and rate of intensity change over time for most emotion categories observed by the autistic child were opposite those observed by the typically developing children. Finally, more complex expressions were seen by the autistic child, but neither group saw changes in expression complexity over time. These findings have implications for understanding the social world from an autistic individual's point of view, and guide the field towards the inclusion of a child's interaction partners into interventions for ASD. Keywords: Autism Spectrum Disorder, emotional facial expressions, children, intensity, complexityHonours; PsychologyThesis