The Puzzle of Altruism Reconsidered: Biological Theories of Altruism and One-Shot Altruism

This paper critically examines the state of the literature in evolutionary biology regarding theories of altruistic behavior. The shared theoretical problems of Kin-selection and Group-selection are examined. Theoretical and severe methodological problems of Reciprocal Altruism theory are also discussed. We offer new conceptual clarifications of the Handicap Principle theory regarding costs and benefits to both the donor and the recipient of an altruistic act. We also summarize supportive empirical studies which demonstrate how Handicap Principle theory easily explains altruistic behavior on a different logic than the one employed by other theories of altruistic behavior. Finally, we discuss the phenomenon of one-shot altruism in order to evaluate, and distinguish between, the predictive and explanatory power of different theories of altruistic behavior.