Human Altruism as a Courtship Display

Abstract

The evolution of altruism by natural selection has been called the central theoretical problem of sociobiology (Wilson 1975:3); it is problematic because altruism seems to imply the unfavorable reduction in the personal reproductive fitness of the altruist. Darwin (1871) related altruism to the moral sense, which he saw as a distinctively human attribute, and evolutionists ever since have been intrigued by the subject. The study of the evolution of social behavior - sociobiology - is founded on Hamilton's quantitative analysis of the type of altruistic behavior that is specifically directed at one's kin (1964a, b). In many cases an increase in the overall reproductive fitness of the genes responsible for the behavior can be clearly seen to occur if all the individuals that carry a proportion of the altruist's genes are included in the calculations (inclusive fitness). Altruistic behavior that is not directed at one's relatives can also be advantageous if it elicits reciprocal behavior (Darwin 1871:163, Trivers 1971). An explanation is needed, however, for ordinary types of human altruistic behavior for which (1) the target is not the altruist's kin and (2) there is no reciprocal altruism. For some such seemingly selfless, and characteristically human, behavior I will offer an explanation in terms of sexual selection. In ordinary language, altruism means a concern for the welfare of others. An evolutionary definition of altruism, which is consistent with the ordinary one, is behavior that increases the reproductive fitness of others at the expense of the altruist. The tactical inclusion of the word apparent conveniently allows us to continue describing a trait as altruistic, as in ordinary usage, even if we should eventually discover that the trait can actually increase, rather than decrease, the reproductive fitness of the altruist, that is, even if the behavior is selfish. I suggest that altruism can be viewed as a courtship display designed as an honest advertisement of the capacity and the intention of the altruist to be a reliable mate