Résumé en anglais

In this paper, we show that behavioral features can be obtained at a group level when the individuals of the group are heterogeneous enough. More precisely, starting from a standard model of Pareto optimal allocations, with expected utility maximizers and exponential dis- counting, but allowing for heterogeneity among agentsíbeliefs and time preference rates, we show that the representative agent exhibits interesting behavioral properties. In particular, we obtain an inverse S-shaped probability distribution weighting function and hyperbolic discounting. We provide possible interpretation as well as applications for this result.