Fondamenti teorici dell'ipotesi di razionalità: il ruolo dell'esperienza

The goal of this paper is to discuss whether maximizing behaviour in consumption can emerge as the long-period outcome of a dynamic process within which consumers follow non-maximizing rules-of-thumb. To discuss this problem we have built two simple dynamic models based on hypotheses and utility functions fully coherent with those of the traditional approach. Both models describe the behaviour of a single consumer who does not know how much the commodities she/he buys fit her/his preferences. These models dynamics depicts a progressive modification of behaviour induced by accumulation of consumption experience. The first model is built under the hypothesis that the consumer is endowed with given preferences but does not fully know how much the bought commodities fit them. It is by repeating the acts of purchasing and consuming that she/he acquires a better fit with her/his preferences. Within this model the difference between the utility ex ante conjectured and the utility ex post realized triggers the dynamics. In this first model the convergence to the maximizing behaviour is possible but it is not a general long-period outcome of the dynamic process. In the second model we assume that consumption not only allows the consumer to better fit her/his preferences, but also induces an endogenous change in these preferences due to the accumulation of consumption experience. In this second model the conditions which allow the maximizing behaviour to emerge are less likely to occur than in the first model.