Marijn Keijzer

Marijn Keijzer is a Research Fellow at the Institute for Advanced Study in Toulouse (IAST) and the Toulouse School of Economics (TSE) in France. His work bridges computational social science, network science, mathematical sociology, and political science, with a focus on understanding social dynamics in digital environments.

Keijzer earned his PhD in Sociology (cum laude) from the University of Groningen, where he was affiliated with the Norms and Networks Cluster and the ICS. Prior to his current position, he served as a Postdoctoral researcher at the Karlsruhe Institute of Technology's Chair of Sociology and Computational Social Science.

His research centers on the emergence of polarization in online social media, micro-macro transitions in opinion dynamics, and social trust. Specifically, he investigates how pro-environmental attitudes form and how to overcome barriers like false polarization, identity-based disagreement, and belief consolidation that hinder collective climate action. Keijzer employs agent-based modeling, survey methods, and experiments to study these phenomena, combining computational approaches with traditional sociological methods.

Keijzer's publication record reveals a sustained focus on polarization mechanisms, with recent work examining YouTube's recommendation algorithms, noise in opinion dynamics, and the relationship between filter bubbles and polarization. His research consistently bridges theoretical modeling with empirical validation, contributing significantly to our understanding of how digital environments shape social dynamics and collective decision-making.

At the Toulouse School of Economics, Keijzer teaches tutorials on Graph Analysis in the masters Econometrics and Statistics program and Data Science for Social Sciences. He previously taught at the BIGSSS Summer School in Computational Social Science in 2022 and 2023, demonstrating his commitment to training the next generation of computational social scientists.