In some situations, a decision is best represented by an incompletely analyzed act: conditionally on a given event A, the consequences of the decision on sub-events are perfectly known and uncertainty becomes probabilizable, whereas the plausibility of this event itself remains vague and the decision outcome on the complementary event ${\bar{A}}$ is imprecisely known. In this framework, we study an axiomatic decision model and prove a representation theorem. Resulting decision criteria aggregate partial evaluations consisting of (i) the conditional expected utility (...) associated with the analyzed part of the decision, and (ii) the best and worst consequences of its non-analyzed part. The representation theorem is consistent with a wide variety of decision criteria, which allows for expressing various degrees of knowledge on ( ${A, \bar{A}}$ ) and various types of attitude toward ambiguity and uncertainty. This diversity is taken into account by specific models already existing in the literature. We exploit this fact and propose some particular forms of our model incorporating these models as sub-models and moreover expressing various types of beliefs concerning the relative plausibility of the analyzed and the non-analyzed events ranging from probabilities to complete ignorance that include capacities. (shrink)

The aim of the paper is to propose a preferences representation model under risk where risk perception can be past experience dependent. A first step consists in considering a one period decision problem where individual preferences are no more defined only on decisions but on pairs (decision, past experience). The obtained criterion is used in the construction of a dynamic choice model under risk. The paper ends with an illustrative example concerning insurance demand. It appears that our model allows to (...) explain modifications in the insurance demand behavior over time observed on the insurance markets for catastrophic risk and difficult to justify with standard models. (shrink)

The aim of this paper is to propose a preferences representation model where ambiguity attitudes can be exogenous events or past experience-dependent. We adapt the Recursive Smooth Ambiguity model proposed by Klibanoff (Journal of Economic Theory 144:930-976, 2009) by introducing past experience described by a sequence of neutral events occurring up to the moment of the decision. These neutral events do not provide any information on the true process, but are likely to strengthen or weaken the decision-maker’s ambiguity aversion degree (...) by modifying emotions. Our model can explain some observed behaviors and market inefficiencies. We propose two illustrations. First, we provide a behavioral explanation for the decrease in influenza vaccination in France that followed the H1N1 crisis in 2009–2010. Second, we contribute to the broad literature on the annuity puzzle by introducing the impact of emotions on ambiguity attitudes. (shrink)

Tribute to Jean-Yves Jaffray by the French Group of Decision Theory.