The Exeter Prize is a prize for the best paper published in the previous calendar year in a peer-reviewed journal in the fields of Experimental Economics, Behavioural Economics and Decision Theory. The winner of the inaugural Exeter Prize 2012 for Research in Experimental Economics, Decision Theory and Behavioral Economics is, "Transitivity of Preferences" by Michel Regenwetter, Jason Dana and Clintin P. Davis-Stober, published in Psychological Review in 2011. This paper examines the theory and empirical methods one might use to differentiate between individual preferences that are simply variable from those that exhibit some structural instability. The authors define the latter as when preferences systematically violate some axiom, and the former as when there is some process, outside the axiom system, affecting preferences.