In this paper, I argue that the responsibility affecting defect of psychopaths is their incapacity for responding to acts within relationships. I begin with Piers Benn's account of psychopaths as incapable of forming participant reactive attitudes. Benn argues that participant reactive attitudes are essentially communicative and the ability to form and understand participant reactive attitudes is crucial to being a member of the moral community. Against Benn, I argue that, although participant reactive attitudes can be communicative, they are not essentially communicative. Instead, they can be simply expressive. Therefore, we must consider psychopaths members of the moral community in Benn's sense; however, psychopaths fail to interpret their actions as part of relationships. This inability renders punishment, as an attempt to rectify wrong relationships, inappropriate for psychopaths. Psychopaths have diminished responsibility, insofar as they have forfeited some rights by committing an offense, but are not appropriate candidates for punishment because they cannot understand its significance.