The Credibility Dilemma in OSNs: Credible Sources as Both Vector and Vaccine for Misinformation

While credible sources are generally viewed as vaccines, they can also act as vectors of misinformation. However, the impact of their endorsement or debunking on user stance and echo chamber dynamics remains unclear. This study analyzes cross-sectional data from the Jiang Ping incident, a nationwide misinformation case in Chinese OSNs, to examine how credible sources influence user polarization and echo chambers over time. We assess their dual role in amplifying and correcting misinformation by tracking changes in stance polarity and interaction patterns across time windows. As the first empirical study of a credible-source misinformation event on this scale, this study offers new insights into the dynamics of credible-source misinformation and contribute to ongoing discussions on platform governance and media literacy.