The WHO Said What? Interaction of Source Credibility and Readers’ Prior Beliefs in the Reading of Social-Media Posts

Evaluating sources is an essential skill in our misinformation-riddled media environment. However, previous studies suggest that people tend not to engage with source information during reading, and very little research exists on how source credibility and readers’ beliefs interact on social media. We examined how source credibility and prior beliefs affect reading social-media posts. Finnish university students ( N = 83) first filled out a questionnaire measuring beliefs on eight controversial topics and then read 76 mock-up tweets on these topics while their eye movements were recorded. The sources of the tweets were pretested to be either credible or noncredible sources for the topic. Eye-movement results indicate that when credible sources say something belief-inconsistent, or if noncredible sources something belief-consistent, reading of the tweet is slower, and more attention is paid to the sources. Findings suggest that these “source-belief” inconsistencies disrupt reading and elicit deeper processing of source information.