Medium of mass misinformation: Repetition increases people's rating of truth for real and satirical headlines

Many people have adopted harmful behaviors in response to the SARS-CoV-2 pandemic, to the detriment of public health and personal safety of others and themselves. While adoption of these behaviors is often attributed to misinformation in the media, people’s tendency to believe previously seen information as being true is also to blame. This tendency, the illusory truth effect, is explained by the similarity in cues between previously seen information and true information, cues such as the ease of processing or a feeling of familiarity. The illusory truth effect has been previously demonstrated with fake news, but not in many other types of misinformation, such as satire. In two experiments, we address the extent to which people come to see headlines—even ridiculous satirical headlines—as being true if they had seen those headlines two days earlier. We found that people tend to rate previously seen headlines as truer than novel headlines, and to a similar extent regardless of whether those headlines were real or satirical. We also found that informing people that some headlines were satirical headlines did not attenuate the illusory truth effect. These results suggest that people rely on the familiarity of information to determine information to be true, regardless of whether that information is ridiculous or if they had been alerted to the presence of misinformation