Edward O. Wilson (1975) proposed to makesociobiologythe core of a ‘new synthesis’ for the study of social behaviour. In general this project has met with either indifference or hostility from students of human nature and society working within the established disciplines, despite theprima facieattractions of developing a genuinely interdisciplinary biosocial science of the person, as both organism and agent.In an attempt to show that there is no fundamental incompatibility between sociobiology and disciplines such as psychology, the essential features of sociobiological theory are outlined, focusing on the concept of ‘inclusive fitness’ and its implications for an understanding of human altruism. It is argued that accounts of the psychological bases of altruism need not be incompatible with sociobiological analyses; and that our most typical forms of behavioural altruism may well involve motivational systems which do normally operate to serve adaptive functions for the individual, even if these can sometimes be overridden. In principle, sociobiological and psychological analyses of human altruism can be developed in parallel, with each providing a useful corrective for the excesses of the other, and stimulating more productive theorizing and more effective empirical r