Judging the Believability of Social Media Misinformation: Source and Message Distinctiveness

Does the source and distinctiveness of misinformation in social media posts affect its believability? Across two studies, we examine this question utilizing vignette experimental survey designs that manipulated the source, accuracy of information, and whether the information was familiar or distinctive (unfamiliar). Four different topics with different political or moral positions were used to assess how effects varied across topics. True posts were found to be more believable than misinformation posts across the four topics in Study one (n = 595). In study two (n = 514), misinformation was rated as more believable, more accurate, and more trustworthy if it was unfamiliar rather than familiar. Source effects were significant but smaller than the distinctiveness effect. Posts from the source of authority were rated as more believable than those from a friend. Distinctive messages receive initial assessments of higher credibility, suggesting a heuristic process. However, the personally relevant topic of COVID, showed higher believability for unfamiliar misinformation, but also a higher percentage intending to verify the information through additional research. Those supporting more conservative views perceived misinformation as more believable. These findings are consistent with the Elaboration Likelihood Model of Persuasion. Implications and directions for future research are discussed.