We study a model of non-Bayesian updating for ambiguity averse agents, based on the Hypothesis Testing model of Ortoleva (2012). Agents have a set of priors that they update as follows. If all priors assign to new information a probability above a threshold, they update every prior using Bayes...

Many violations of the independence axiom of expected utility can be traced to subjects' attraction to risk‐free prospects. The key axiom in this paper, negative certainty independence ([Dillenberger, 2010]), formalizes this tendency. Our main result is a utility representation of all...

Bayes' rule has two well-known limitations: 1) it does not model the reaction to zero-probability events; 2) a sizable empirical evidence documents systematic violations of it. We characterize axiomatically an alternative updating rule, the Hypothesis Testing model. According to it, the agent...

This article presents the results of a laboratory experiment and an online multi-country experiment testing the effect of motor vehicle eco-labels on consumers. The laboratory study featured a discrete choice task and questions on comprehension, while the ten countries online experiment included...