Conformity, reciprocity and the sense of justice. How social contract-based preferences and beliefs explain norm compliance: the experimental evidence

Compliance with a social norm is a matter of self-enforceability and endogenous motivation to conform, which is relevant not just to social norm,s but also to a wide array of institutions. Here we consider endogenous mechanisms that become effective once the game description has been enriched with pre-play communication allowing impartial agreements on a norm (even if they remain not binding in any sense). Behavioral models understand conformity as the maximization of some �enlarged� utility function properly defined to make room for the individual�s �desire� to comply with a norm reciprocally adhered to by other participants � whose conformity in turn depends on the expectation that the norm will be in fact reciprocally adhered to. In particular this paper presents an experimental study on the �conformity-with-the-ideal preference theory� (Grimalda and Sacconi 2005), based of a simple experimental three person game called the �exclusion game�. If the players participate in a �constitutional stage� (under a veil of ignorance) in which they decide the rule of division unanimously, the experimental data show a dramatic change in the participants� behavior pattern. Most of them conform to the fair rule of division to which they have agreed in a pre-play communication stage, whereas in the absence of this agreement they behave egoistically. The paper also argues that this behavior is largely consistent with what John Rawls (1971) called the �sense of justice�, a theory of norm compliance unfortunately overlooked by economists and which should be reconsidered after the behaviorist turn in economics.