Facial impression of trustworthiness biases statement credibility unless suppressed by facemask

The impression of trustworthiness based on someone's facial appearance biases our subsequent behavior toward that subject in a variety of contexts. In this study, we investigated whether facial trustworthiness also biases the credibility of utterances associated with that face (H1). We explored whether this bias is mitigated by utterances eliciting reasoning, i.e. explanations (as opposed to factual statements; H2). Moreover, we hypothesized that overimposing facemasks on those faces could enhance/reduce utterance credibility due to social value of mask-wearing (H3), and that facemasks could counter the putative credibility bias introduced by facial trustworthiness (H4). If so, this may be either because facemasks remove the visual information necessary for trustworthiness impression (H4a), or because information is less salient, although it can be retrieved under different circumstances (H4b). An online study (N = 159) was conducted to test these hypotheses. In the first task, subjects saw 48 facial pictures coupled with one utterance and judged the truthfulness/falsity of this utterance. In the second task, they saw again 16 of the faces from the previous tasks and were asked to recall whether the associated utterance was true or false. Findings from the first task support H1 and H4, but not H2 and H3. However, in the second task, where the face is the only available cue, the credibility-mitigation bias exerted by facemask disappears, supporting H4b over H4a. Our results confirm the pervasivity of facial trustworthiness impressions in social cognition, and suggest that facemask can mitigate them, or at least their salience.