Lorenzo Sacconi / Marco Faillo / Stefania Ottone Contractarian Compliance and the 'Sense of Justice': A Behavioral Conformity Model and Its Experimental Support 273-310 Abstract: The social contract approach to the study if institutions aims at providing a solution to the problem of compliance with rational agreements in situations characterized by a conflict between individual rationality and social optimality. After a short discussion of some attempts to deal with this problem from a rational choice perspective, we focus on John Rawls's idea of 'sense of justice' and its application to the explanation of the stability of a well-ordered society. We show how the relevant features of Rawls's theory can be captured by a behavioral game theory model of beliefs-dependent dispositions to comply, and we present the results of two experimental studies that provide support to the theory.