Reciprocity is one of the basic norms of human being. However, it is still neglected in political science. It refers to an individuals' in-kind response to friendly or hostile acts. Previous research from other disciplines has shown that reciprocity generates positive externalities and implies the maintenance of stable social societies. For example, it fosters the probability of an individual’s political participation. Gutman and Thompson (1998) even promote the norm of reciprocity as the basis of deliberative democracy. Under reciprocity, individuals use deliberation with the goal of reaching deliberative agreement that, in turn, supports a political process fostering moral learning. However, reciprocity is difficult to measure and previous research rather refers to trust and trustworthiness. By online experiments, surveys and multi-level analysis, this study aims to measure reciprocity in a comparable way to analyse in a second step the relationship between the norm and a country’s quality of democracy.