We study the relation between ambiguity aversion and the Allais paradox. To this end, we introduce a novel definition of hedging which applies to objective lotteries as well as to uncertain acts, and we use it to define a novel axiom that captures a preference for hedging which generalizes the...

We derive a new hedge ratio based on weighted expected utility. Weighted expected utility is a generalization of expected utility that permits non-linear probability weights. Generally speaking weighted expected utility hedge ratios are less than minimum variance hedge ratios and larger than...

We study the relation between ambiguity aversion and the Allais paradox. To this end, we introduce a novel denition of hedging which applies to objective lotteries as well as to uncertain acts, and we use it to dene a novel axiom that captures a preference for hedging which generalizes the one...

De tous les problèmes conçus par la théorie de la décision, le paradoxe d'Allais est peut-être celui qui aura suscité l'intérêt le plus persistant. La théorie y a consacré assez de travaux techniques remarquables pour qu'il soit désormais possible à l'histoire et à la philosophie...

We report the results of an experimental test of whether preaching the normative appeal of the sure-thing principle leads decision-makers to make choices that satisfy it. We use Allais-type decision problems to observe the incentive-compatible choices of 147 subjects, which either violate the...

This chapter of a collective book aims at presenting the basics of decision making under risk. We first define notions of risk and increasing risk and recall definitions and classifications (that are valid independently of any representation) of behavior under risk. We then review the classical...

The Allais Paradox, or common consequence effect, has been a standard challenge to normative theories of risky choice since its proposal over 60 years ago. However, neither its causes nor the conditions necessary to create the effect are well understood. Two experiments test the effects of...

The phenomenon of "choice shifts" in group decision-making is fairly ubiquitous in the social psychology literature. Faced with a choice between a ``safe" and ``risky" decision, group members appear to move to one extreme or the other, relative to the choices each member might have made on her...