L'economia sperimentale e l'offerta volontaria di beni pubblici

When we try to implement a model of voluntary provision of public goods in order to reach the optimal level of the supply of public goods, it is an established result that we may only get to a sub-optimal level. This result is due to the presence of strong incentives accruing to the agents in order to adopt the free-riding strategy leading to the Nash equilibrium. If we test this result through the experimental procedure, we usually find that, on the average, individual contributions to the public goods are consistently greater than zero, which is the value predicted by the game-theoretic approach. This striking finding has been massively studied in the experimental literature. The aim of this paper is, first of all, to describe the methodology and the basic tools of experimental economics. Then, in order to make the functions of those tools clear, we will present one of the theoretical model most widely adopted when designing experiments with public goods. Once having defined the basic experimental features, we will review some of the most interesting experimental works emphasizing the experimental design and results of each of them. The last part of our paper will be devoted to the analysis of the effects of the interpersonal relationships and emotional responses, induced by public goods experiments, on the individual contribution levels to the provision of public goods.