This paper presents a generalization of the DeGroot learning rule in which social learning can lead to polarization, even for connected networks. I first develop a model of biased assimilation in which the utility an agent receives from past decisions depends on current beliefs when uncertainty...

This paper studies an agent forming beliefs by translating data into signals about the truth of propositions. The agent faces ambiguity when she observes low-quality data yielding set-identified signals. Rules for decision-making under ambiguity choose the single belief generating an extreme...