Nature 228, 1218 - 1220 (19 December 1970); doi:10.1038/2281218a0

Selfish and Spiteful Behaviour in an Evolutionary Model

W. D. HAMILTON

Imperial College Field Station, Silwood Park, Ascot, Berks.

INCIDENTS in which an animal attacks another of the same species, drives it from a territory, or even kills and devours it are commonplace. They may be described as examples of biological selfishness. The effect consists of two obvious parts: the gains (in fitness) of the victor and the losses of the victim. Attempts to secure the gains are easily understood to be adaptive: this is the fundamental response to what Darwin called the "struggle for existence". But, considering the more controversial catch-phrase of evolutionary theory—"the survival of the fittest"—it seems to be a neglected question whether the harm delivered to an adversary is always merely an unfortunate consequence of adaptations for survival. Could such harm ever be adaptive in itself ? Or nearer, to the possibility of a test, would we ever expect an animal to be ready to harm itself in order to harm another more ? Such behaviour could be called spite. Is it ever observed ?

References

1.	Hamilton, W. D., Amer. Nat., 97, 354 (1963).
2.	Hamilton, W. D., J. Theor. Biol., 7, 1 (1964).
3.	Hamilton, W. D., in Man and Beast: Comparative Social Behaviour (Proc. Smithsonian Institution Third Intern. Symp., 1969) (in the press).
4.	Price, G. R., Nature, 227, 520 (1970).
5.	Wright, S., Amer. Nat., 56, 330 (1922).
6.	Wright, S., Genetics, 19, 395 (1965).
7.	Wright, S., Ann. Eugenics, 15, 323 (1951).
8.	Wright, S., Bull. Amer. Math. Soc., 48, 223 (1942).
9.	Orians, G. H., and Willson, M. F., Ecology, 45, 736 (1964).
10.	Marshall, A. J., Bowerbirds (Oxford Univ. Press, 1954).
11.	Corbet, P. S., and Griffiths, A., Proc. Roy. Entomol. Soc., A, 38, 125 (1963).
12.	Kirkpatrick, T. W., Insect Life in the Tropics (Longmans, London, 1957).
13.	Walker, M. G., Canad. J. Res., 20, 235 (1942).