Common and distinct impacts of autistic traits and alexithymia on social reward.

According to the social motivation hypothesis of autism, individuals with high levels of autistic traits experience reduced levels of reward from social interactions. However, empirical evidence to date has been mixed, with some studies reporting lower levels of social reward in individuals with Autism Spectrum Disorder (ASD), and others finding no difference when compared to typically developing controls. Alexithymia, a subclinical condition associated with the reduced ability to identify and describe one's own emotions, has been found to account for other affective difficulties observed inconsistently in individuals with ASD. The current study used a nonclinical sample (N = 472) to explore the associations between autistic traits and the value of six types of social reward, as measured by the Social Reward Questionnaire. In addition, we measured alexithymia to assess if this accounted for associations between autistic traits and social reward. There were three main findings. Firstly, higher levels of autistic traits were associated with significantly less enjoyment of admiration and sociability, and adding alexithymia to these models did not account for any additional variance. Secondly, both autistic traits and alexithymia were uniquely associated with reduced levels of enjoyment of prosocial interactions and sexual relationships. Thirdly, autistic traits were associated with higher levels of enjoyment of passivity and negative social potency, but these associations were no longer significant once alexithymia was taken into account, suggesting that co-occurring alexithymia accounted for these apparent associations. Overall, the current findings provide a novel and more nuanced picture of the relationship between autistic traits and social reward.