AI tools used to generate, edit or contextualize social media posts can introduce hidden biases that spread through online networks and shape public opinion, according to new research from the Oxford Internet Institute (OII) at the University of Oxford and the Hasso Plattner Institute at the University of Potsdam.
The study found that large language models (LLMs) consistently changed the direction of social media posts on contested topics, even when explicitly instructed to preserve the original meaning. The researchers also showed, through simulations of real-world social networks, how these small changes could accumulate across millions of interactions and gradually influence broader public opinion.
The findings raise questions about the growing use of AI-powered writing tools on social media platforms and suggest that AI-mediated communication could become a powerful new mechanism for influencing public discourse.
The study, authored by Dr. Stratis Tsirtsis, Kai Rawal, Chris Russell, Brent Mittelstadt and Sandra Wachter, has been accepted for presentation at the AI4Good and Technical AI Governance Research workshops at the International Conference on Machine Learning (ICML 2026) in Seoul, South Korea. The research is published on the arXiv preprint server.
