How social media can undermine democracy

Abstract

We examine the influence a self-interested social-media platform can have on election outcomes. Using the framework of the Condorcet Jury Theorem, we explore the effect of additional information via private messages from the platform, modeled through Bayesian persuasion. We establish conditions under which the platform can sway the majority voting outcome, assuming voters vote sincerely. Additionally, we demonstrate that the information disseminated by the platform can sometimes be biased in the opposite direction of the platform’s interests.