Objectives: To examine implicit processing of social-affective information in individuals with ASD using (1) magnitude and frequency of skin conductance responses (SCRs) and (2) pupil dilation.
Methods: Individuals with ASD, matched on age with normal controls (NCs), passively viewed static emotionally-laden images (from the International Affective Picture System, IAPS) based on their content: social threatening, non social threatening and angry and fearful faces. Skin conductance responses and changes in pupil diameter were collected using the BIOPAC MP150 Systems and Tobii-1750 eye-tracker, respectively.
Results: Overall the ASD group was more electrodermally responsive than typical controls; the ASD group had significantly more SCR’s for all images than the NC group. In addition, greater pupil diameter changes were observed in the ASD group when viewing faces compared to social and non-social threatening images.
Conclusions: The ASD group’s hyperarousal to faces is consistent with findings of (1) hyperactivation of the amygdala and, (2) social aversion, especially to direct gaze, in ASD. This work supports the notion that increased autonomic responsiveness may underlie impairments in face recognition observed in ASD. Further work is needed to elucidate what mechanisms underlie the hyperarousal to faces observed in ASD.