The influence of intentional stance on the neural encoding of joint attention

Adopting an intentional stance towards a social partner is a crucial component of evaluating the success of joint attention, where social interlocuters must represent the mind and perspectives of others. Recent work has established that centroparietal P250 and P350 ERPs are sensitive to whether the gaze shifts of others signal the achievement or avoidance of joint attention, and that this modulation depends on the adoption of an intentional stance (Caruana & McArthur, 2019). The current study attempted to replicate these effects, determining their reliability across testing contexts, and examining the influence of the aesthetic anthropomorphism of the stimuli used. Participants initiated gaze-cued joint attention bids with an on-screen virtual partner, which shifted its eye gaze congruently to respond to joint attention bids on 50% of trials and responded incongruently to avoid joint attention on the remaining trials. Participants were told that in one block their partner was controlled by a human, and in another by a computer program. The aesthetic anthropomorphism of the faces was manipulated between-subjects so that one group interacted with an animated human face (n=21), and the other interacted with a humanoid robot face (n=19) . Larger P250 mean amplitudes were measured in response to congruent gaze shifts compared to incongruent, and the opposite pattern was observed for P350 responses. However, these ERPs were not reliably modulated by the adoption of an explicit intentional stance across both stimulus groups. We found tentative evidence to suggest that this unreliability may be explained by individual differences in anthropomorphism tendencies.