'Heroism' in Warfare

The willingness of people to risk their lives fighting on behalf of their nation (which we call heroism) is a background assumption in the study of war, thus of international relations, but also an evolutionary puzzle. We use two computer simulations to explore the possibility that heroism could have evolved as a domain specific form of altruism, selected through humans’ ancient past as a consequence of warfare. In the first, “altruism” is modeled as a generalized disposition that promotes both heroism and other, non-military, forms of group-benefiting behaviors—which we call communitarianism. In the second, heroism and communitarianism are modeled as domain specific dispositions free to evolve independently. Warfare promotes weak selection on generalized altruism, somewhat stronger selection on communitarianism, and substantial selection on heroism. Heroism evolves more readily when groups are small and relatively equal in size. However, the level of evolved heroism is unaffected by whether war is rare or common. An analytic model indicates that heroism should evolve to higher levels when the rate of casualties in defeated groups is high. Our results suggest why special purpose modes of altruism might evolve more readily than a generalized propensity for altruistic behavior. When Homer asks in the Iliad “What god drove them to fight with such a fury?” he was posing a question that remains problematic three thousand years later: What makes soldiers willing to fight at great personal risk for their polis, their tribe, their ethnic group, or their country? There is no doubt that soldiers often do fight in this manner. In spectacular cases, of course, they have invited almost certain death by, for example, throwing themselves on grenades in order to save their comrades, but the history of warfare is, in large part, the history of ordinary men (and, in recent times, women) who willingly confronted the risk of death when fighting for their tribe, country, or other group. In the present paper we call this behavior “heroism.” Heroism is well recognized as a potential human behavior, but the existence of heroism is most commonly treated as a background assumption in examining the nature of war. In this paper we address what we see as the central puzzle of heroism: How could it have evolved? Most studies that address the puzzle of why people are willing to fight on behalf of a group have focused on “proximate” answers—emotional, cognitive or other mechanisms that prompt such behavior in the here and now. Thus, for example, loyalties to small groups of 1 Stories about such behavior are not apocryphal. According to Holmes (1985, p. 300), “Of the eight medals won by Marines on Peleliu in 1944, six were awarded to men who covered grenades with their bodies to save their comrades....” And, quoting a history of the US Marine Corps by Robert Moskin: “Five black Marines earned the Medal of Honor in Vietnam. All five were killed shielding their fellow Marines from exploding enemy grenades.” Not all who did this were actually killed; Holmes reports that two winners of the Medal of Honor in Korea survived having thrown themselves on grenades. Yet the risk of death from such action is, clearly, very high.