A single exposure to cancer misinformation may not significantly affect related behavioural intentions

Background: In recent years, rates of online cancer misinformation have grown, with many concerned that this could lead patients to alter their daily behaviours or forego conventional treatment. However, no published study has investigated whether exposure to cancer misinformation can affect health behaviours or behavioural intentions. Method: In this preregistered study, participants (N = 774) were exposed to cancer misinformation in the form of news stories before rating their intentions to engage in related behaviours. Each participant was randomly presented with two of four possible false cancer headlines such as “Drinking fluoridated water shown to increase cancer risk by a factor of 3”, before rating their intentions to engage in certain behaviours (such as avoiding fluoridated water). Participants were also randomly assigned to either an accuracy-nudge intervention intended to reduce susceptibility to misinformation or a control condition with no intervention. Results: Viewing the fake cancer headlines did not significantly affect participants’ behavioural intentions – e.g., those who saw the headline regarding fluoridated water were not more likely to report intentions to reduce their fluoridated water intake. The accuracy-nudge intervention did not affect behavioural intentions. Conclusion: Although cancer misinformation is considered a threat to public health, we conclude that once-off exposures to cancer misinformation may not be sufficient to significantly alter behavioural intentions. We note that claims about the effects of cancer misinformation on behaviour have not been adequately researched and we therefore call for more research into the behavioural effects of cancer misinformation exposure, particularly repeated exposure or information passed from trusted sources.