Bocconi University Assistant Professor Simone Cerreia Vioglio, Assistant Professor of Economics at Bocconi University, presents preliminary research on self-confirming long run biases. He and his collaborators consider a myopic decision maker facing a recurrent decision problem. They show that a long run bias emerges that favors “tested” actions, that is, actions on which information has been collected over time. In so doing they provide, inter alia, a learning foundation for the self-confirming equilibrium with model uncertainty of Battigalli et al. (2011). This lecture is a part of the Workshop on Ambiguity and Robustness in Macroeconomics and Finance.