Econometrica: May, 2020, Volume 88, Issue 3
Social Learning Equilibria
Elchanan Mossel, Manuel Mueller‐Frank, Allan Sly, Omer Tamuz
We consider a large class of social learning models in which a group of agents face uncertainty regarding a state of the world, share the same utility function, observe private signals, and interact in a general dynamic setting. We introduce social learning equilibria, a static equilibrium concept that abstracts away from the details of the given extensive form, but nevertheless captures the corresponding asymptotic equilibrium behavior. We establish general conditions for agreement, herding, and information aggregation in equilibrium, highlighting a connection between agreement and information aggregation.
Supplement to "Social Learning Equilibria"
This supplementary appendix presents additional extensions and results. The first concerns the case of heterogeneous types of agents, with the corresponding result following immediately from the results established in the paper. The second extension relaxes the assumption of binary states and actions inherent in the canonical setting.