Autistic traits moderate the impact of reward learning on social behaviour

A deficit in empathy has been suggested to underlie social behavioural atypicalities in autism. A parallel theoreticalaccount proposes that reduced social motivation (i.e., low responsivity to social rewards) can account for the saidatypicalities. Recent evidence suggests that autistic traits modulate the link between reward and proxy metrics relatedto empathy. Using an evaluative conditioning paradigm to associate high and low rewards with faces, a previous studyhas shown that individuals high in autistic traits show reduced spontaneous facial mimicry of faces associated withhigh vs. low reward. This observation raises the possibility that autistic traits modulate the magnitude of evaluative con-ditioning. To test this, we investigated (a) if autistic traits could modulate the ability to implicitly associate a rewardvalue to a social stimulus (reward learning/conditioning, using the Implicit Association Task, IAT); (b) if the learnedassociation could modulate participants’ prosocial behaviour (i.e., social reciprocity, measured using the cyberball task);(c) if the strength of this modulation was influenced by autistic traits. In 43 neurotypical participants, we found thatautistic traits moderated the relationship of social reward learning on prosocial behaviour but not reward learning itself.This evidence suggests that while autistic traits do not directly influence social reward learning, they modulate the rela-tionship of social rewards with prosocial behaviour