Public information campaigns often warn people about false and unreliable medical claims by juxtaposing myths and facts. The effectiveness of such communications has rarely been assessed. We assessed whether people systematically misremember the myths (false information) as true, and to assess effects on perceptions of risk and behavioral intentions.~In an experimental study, participants read either a published CDC flyer on Facts and Myths about the flu vaccine, or a Facts Only version; a separate control group read no flyer. Participants completed the outcome measures either immediately or after 30 minutes.~Primary measures were memory for information about the flu presented in the flyer, ratings of perceived risks associated with the flu, and personal intentions to get vaccinated in the upcoming season.~After a delay of 30 minutes, participants who read the Facts and Myths flyer systematically misremembered myths as facts. Both versions of the flyer had the immediate effect of increasing intentions to get a flu vaccine, compared to the control group. After 30 minutes, however, participants who read the Facts and Myths flyer reported lower intentions to get vaccinated, compared to those who read the same flyer with no delay, and compared to all participants who read the Facts Only flyer.~In sum, people show a bias to think that incompletely remembered information is true, turning myths into facts. Hence public information campaigns should emphasize information that is true. Repeating false information, even as a warning, can create the unintended consequence of belief in the information.
Objectives: To determine whether people systematically misremember the myths (false information) as true, and to assess effects on perceptions of risk and behavioral intentions.