Boosting psychological defences against misleading content online is an active area of research, but transition from the lab to real-world uptake remains a challenge. We developed a 19-second prebunking video about emotionally manipulative content and showed it as a Story Feed ad to N = 375,597 Instagram users in the United Kingdom. Using an innovative method leveraging Instagram’s quiz functionality (N = 806), we found that treatment group users were 21 percentage points better than controls at identifying manipulation in a news headline, with effects persisting for five months. Treated users were also more likely to click on a link to learn more. We outline how inoculation campaigns can be scaled in real-world social media feeds.
