You sure about that? The effects of textual and image-based Skepticism on belief in dubious social-media claims

On social media, people often react to posts using both written comments and images. While prior work has shown that these reactions can influence belief in claims, it has often conflated signals of (dis)endorsement with justifications of dissent. It is therefore unclear whether skeptical comments that express doubt about a claim's veracity without providing informational content can reduce claim belief. We tested whether pure text- or image-based expressions of skepticism reduce belief in dubious claims, and how skepticism compares with non-evidence-supported rebuttals that explicitly declare a claim to be false, in the presence versus absence of supportive comments that express general acceptance or agreement with a claim. Participants (N = 200) rated their belief in true and false claims presented as social-media posts with varying combinations of supportive, skeptical (textual vs. image-based), or non-evidence-supported negational comments. Results showed that supportive comments were associated with greater claim belief, while skeptical comments reduced belief, with no difference between text and image formats. Direct negations had the strongest corrective effect despite not providing any evidence. Implications are discussed, including the risk of skepticism reducing belief in true claims, underscoring the need for oversight of community-based fact-checking tools on social media.