Preference for equivalent random variables: A price for unbounded utilities

Savage's expected utility theory orders acts by the expectation of the utility function for outcomes over states. Therefore. preference between acts depends only on the utilities for outcomes and the probability distribution of states. When acts have more than finitely many possible outcomes, then utility is bounded in Savage's theory. This paper explores consequences of allowing preferences over acts with unbounded utility. Under certain regularity assumptions about indifference, and in order to respect (uniform) strict dominance between acts, there will be a strict preference between some pairs of acts that have the same distribution of outcomes. Consequently in these cases, preference is not a function of utility and probability alone. (C) 2009 Elsevier B.V. All rights reserved.