To Share or Not to Share: Randomized Controlled Study of Misinformation Warning Labels on Social Media

Can warning labels on social media posts reduce the spread of misinformation online? This paper presents the results of an empirical study using ModSimulator, an open-source mock social media research tool, to test the effectiveness of soft moderation interventions aimed at limiting misinformation spread and informing users about post accuracy. Specifically, the study used ModSimulator to create a social media interface that mimics the experience of using Facebook and tested two common soft moderation interventions – a footnote warning label and a blur filter – to examine how users (n = 1500) respond to misinformation labels attached to false claims about the Russia-Ukraine war. Results indicate that both types of interventions decreased engagement with posts featuring false claims in a Facebook-like simulated interface, with neither demonstrating a significantly stronger effect than the other. In addition, the study finds that belief in pro-Kremlin claims and trust in partisan sources increase the likelihood of engagement, while trust in fact-checking organizations and frequent commenting on Facebook lowers it. These findings underscore the importance of not solely relying on soft moderation interventions, as other factors impact users’ decisions to engage with misinformation on social media.