When Trust Makes You Sceptical: Scrutiny Mediates the Effect of Perceived Source Dishonesty on Truth Judgments for Those With High Dispositional Trust

The effects of perceived source honesty have been studied extensively in the context of persuasion, but their role in truth judgments has been neglected. The incongruence of information veracity and the perceived honesty of its source (e.g., true information from dishonest sources or false information from honest sources), could increase scrutiny of information. An exploratory study (N = 410) tested the effects of the congruence of veracity and perceived source honesty on scrutiny of, and belief in, true and false information. In a 2 (honest vs. dishonest source) by 2 (true vs. false statements) between-subjects online experiment, participants rated the perceived veracity of 30 general knowledge statements before completing a statement scrutiny scale and exploratory measures like dispositional distrust (a potential moderator of source effects on scrutiny). A moderated mediation analysis shows that the incongruent combination of true information from dishonest sources increases scrutiny, while no such effect was found for false information or congruent combinations. Higher levels of scrutiny then have a negative effect on truth ratings, meaning that scrutiny reduces rather than improves the accuracy of truth judgments in this case. While the interaction between source honesty, veracity, and dispositional trust was not significant, exploratory analyses suggest that the conditional indirect effect of source dishonesty on truth judgments via scrutiny is significant for people with high levels of dispositional trust (but not those with low levels). Overall, those with high levels of dispositional trust seem to be led astray by veracity-incongruent source information in their truth judgments. The absence of this indirect effect for the other incongruent source-veracity combination (i.e., false information from sources perceived as honest) implies that people err on the sceptical side in judging truth when there is a mismatch between perceived source honesty and veracity.