Reciprocity is in this contribution compared with cooperation, hostility, and prosociality, in order to distinguish its peculiar theoretical and empirical characteristics. Two studies are presented. Study 1 (n = 166) is based on the distinction between the mechanism of reciprocity and the consequent behaviour that this mechanism produces. It is shown that participants have a clear implicit theory of the personality traits underlying reciprocal behaviour, and these traits are well differentiated with respect to traits underlying cooperation and hostility. Study 2 (n = 134) is based on the distinction between reciprocity as a goal and reciprocity as a strategy to achieve equality. Results show that individuals with high internalization of the norm of reciprocity allocate payoffs as a function of the valence of other's past behaviour, whereas this feature is irrelevant for individuals with high prosocial orientation. Copyright © 2001 John Wiley & Sons, Ltd.