The Two Sides of Warfare
Building on and partially refining previous theoretical work, this paper presents an extended simulation model of ancestral warfare. This model (1) disentangles attack and defense, (2) tries to differentiate more strictly between selfish and altruistic efforts during war, (3) incorporates risk aversion and deterrence, and (4) pays special attention to the role of brutality. Modeling refinements and simulation results yield a differentiated picture of possible evolutionary dynamics. The main observations are: (a) Altruism in this model is more likely to evolve for defenses than for attacks. (b) Risk aversion, deterrence, and the interplay of migration levels and brutality can change evolutionary dynamics substantially. (c) Unexpectedly, one occasional simulation outcome is a dynamically stable state of “tolerated intergroup theft,” raising the question as to whether corresponding patterns also exist in real intergroup conflicts. Finally, possible implications for theories of the coevolution of bellicosity and altruism in humans are discussed.
KeywordsIntergroup conflict Cooperation Public goods Altruism Warfare
I thank Max Albert, Charlotte Störmer, Eckart Voland, and Human Nature’s anonymous reviewers for very valuable criticism. Prudent copy-editing by Mary June-el Piper is gratefully acknowledged. This publication represents a component of my doctoral thesis (Dr. rer. nat.) in the Faculty of Biology at the Justus-Liebig-University Giessen, Germany.
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