Altruism as a Signal: Zahavi's Alternative to Kin Selection and Reciprocity

Abstract

Zahavi (1995) refutes the logic of kin selection and reciprocity, and proposes an alternative signalling explanation for the evolution of altruism. This paper expands upon Zahavi's promising as a handicap argument, in which altruists improve their future fitness as a result of honestly signalling their phenotypic quality to prospective mates or allies. It is suggested that cooperative systems may be especially likely to evolve signals using altruism as a handicap, because signalling costs could be recouped within the collaboration (e.g. mate choice based on courtship feeding also increases female reproductive output). However, the claim that the altruism inherent in helping-at-thenest has evolved to enhance the of helpers within the group seems unlikely on the basis of current evidence. The utility of the concept of social prestige is also questionable, particularly when compared to related and overlapping ideas already in use, concerning dominance, reciprocity and affiliative behaviour. In order to generate a need for the alternative hypothesis, misleading arguments have been presented concerning the similarities between kin selection and group selection, and the evolutionary stability of cooperation and reciprocation. This confusion seems rather unnecessary, because altruism as a signal is compatible with these other well-established theories. Further work is now required in the form of mathematical game theory models to explore the evolutionary stability of altruism as a signal.