Selfish and Spiteful Behaviour in an Evolutionary Model

Abstract

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 ?