Discriminating Between Models of Ambiguity Attitude: a Qualitative Test

The exchange between Epstein (2010) and Klibanoff et al. (2012) identified a behavioral issue that sharply distinguishes between two classes of models of ambiguity sensitivity, exemplified by the I±-MEU model and the smooth ambiguity model, respectively. The issue in question is whether a subject’s preference for a randomized act (compared to its pure constituents) is influenced by a desire to hedge independently resolving ambiguities. Building on this insight, we implement an experiment whose design provides a qualitative test that discriminates between these importantly distinct classes of models. Among subjects identified as ambiguity sensitive, we find greater support for the class exemplified by the smooth ambiguity model; the relative support is stronger among subjects identified as ambiguity averse.