Participant characteristics (N = 1051).

BackgroundCancer treatment misinformation (e.g., false cures) is shared widely on social media and harmful. Cancer treatment misinformation is potentially shared because people want to help or provide hope for those with cancer. We need strategies, like prompts that inform others that a post may be false, to redirect individuals to prosocially intervene instead of sharing to reduce cancer treatment misinformation.ObjectiveWe examined whether social cue prompts with a post review policy would lead to more intervening and less sharing of cancer treatment misinformation.MethodsWe conducted a between-persons online experiment with adult participants from the US recruited via Prolific. Participants were randomized to view cancer treatment misinformation social media posts with social cue prompts and a flagging policy (treatment) or no prompts or policy (control) and reported willingness for intervening (e.g., flagging), sharing, and message reactions. Participants also reported their motivations for intervening or sharing the posts.ResultsSocial cue prompts and policies for platform action encouraged participants to intervene (e.g., flag) significantly more than people who did not see prompts, p p p p ConclusionPrompts (also called warnings, nudges, or labels) on cancer treatment misinformation are a promising approach to encourage intervening (flagging) and reduce sharing on social media. Social cue prompts and policies also reduced common motivations for sharing – to help and provide (false) hope – that could be interpreted as misguided altruism.