This paper is about social action in the field of political culture and aims at understanding the capacity of individuals to hold to the values and norms that orientate a democratic society. It focuses the analysis on the reciprocity between actors and the systems of exchanges and between actors and institutions, taking into account cultural values and social capital. It considers the Brazilian cultural tradition of supporting ambiguous values in social exchanges, both in the public and the private spheres, intensifying ambivalences, paradoxes and producing a hybrid mode of institutional functioning, combining informal and formal rules and norms. The analysis of this issue is developed in relation to the meaning of liberty, obligation and trust concerning the rights and duties that configure social identity and individual political participation, in the way they are related to exchanges and reciprocity in the democratic Brazilian society.