The impact of partially covered faces on trust attribution, sharing resources, and perceived fairness of one's own choices in Ultimatum Game.

Covered faces have been linked with impaired emotion recognition; yet, it is entirely unexplored how an occlusion due to face masks may affect individuals' behaviour in economic decisions. Across two studies, we explored whether partially covered faces (due to mask wearing or a horizontal black bar) and emotion displayed by the responder influence peoples' sharing behaviour in the Ultimatum Game and the perceived fairness of one's proposal.Study 1 showed participants were more willing to equally share their resources with a happy face (compared to a neutral one). In addition, they were more willing to make a fair proposal when the person displayed was not wearing a face mask. Our results also provide evidence that, when people had to judge how fair their proposal was, participants rated a fair proposal as fairer when responders showed happy faces without masks, while unfair proposals were rated as fairer with happy masked faces; similarly, angry faces led to fairer ratings for fair offers without masks and unfair offers with masks. Study 2 partially confirmed previous results, highlighting how a simple occlusion on the face does not have a direct effect on the proposal but moderates the effect of the displayed emotions.These findings indicate that social interactions might be affected by face occlusion, especially when it is represented by a face mask. Indeed, people might judge the same behaviour in different ways based on the fact that their counterpart has a partially covered face.