The spread of misinformation on social media is a persistent challenge. Researchers, policymakers, and social media platforms have proposed various interventions to mitigate the proliferation of low-quality information. Most existing approaches focus on content-based solutions, such as fact-checking, inoculation, and accuracy prompts.

An alternative strategy is to shift focus from content to sources, providing users with evidence about the authenticity or trustworthiness of social media accounts. This source-based approach might be particularly compelling for the small number of “disinformation superspreaders” that disproportionately drive the proliferation of false information.

Building on research on the effects of misinformation, this paper studies how source verification schemes influence users’ social media behaviour, their perception of news accuracy, and their political attitudes. We consider both positive effects of source-rating (such as facilitating the distinction between accurate and fake news) and possible negative effects (reinforcing negative emotions or anti-elite attitudes). We rely on two pre-registered experiments conducted in the US (with a total of more than 5000 respondents), implemented using a simulated social media tool (The Misinformation Game), embedded in an online survey. We investigate how different types of source-verification schemes (3-5 experimental conditions, depending on the experiment) influence social media engagement, perceived message accuracy, perception of platform trustworthiness, as well as various political attitudes. We also consider how these effects vary between politically contested issues (immigration) and non-political topics (sunscreen safety).