Personality reveals distinct behavioral and neural patterns of social cognition in autism

Autism spectrum disorder is characterized by substantial heterogeneity in social-cognitive functioning, yet individual differences contributing to this variability remain poorly understood. Personality provides a normative framework for characterizing such differences across diagnostic boundaries. Here, we investigated whether personality, particularly agreeableness, relates to behavioral and neural variability in social cognition in autistic young adults without intellectual and language impairment. Thirty-eight autistic participants were compared with a large neurotypical sample for personality and with neurotypical individuals selected with high (HA) or low (LA) agreeableness during three EEG paradigms examining social-interaction perception, basic emotion recognition, and complex mental-state decoding. Autistic participants showed lower agreeableness, extraversion, and conscientiousness and higher neuroticism than neurotypical participants, with substantial interindividual variability. Their agreeableness scores were closer to those of LA than HA participants. Behavioral differences were selective: autistic participants showed lower accuracy than HA participants during complex mental-state decoding, whereas no significant difference was detected relative to LA participants or during the other social-cognitive tasks. Neural activity revealed a more nuanced pattern. No significant group differences emerged during social-interaction perception or basic emotion recognition. In contrast, decoding of complex mental states from the face revealed group differences in the ERP component N170 and a smaller Late Slow Wave (LSW) response in autistic participants. The LSW difference was more extensive relative to HA than to LA neurotypical participants. Overall, these findings highlight the importance of considering individual variability at both behavioral and neural levels, as similar behavioral outcomes may reflect distinct neural processing.