Pandit Sagar, Pradhan Gauri, van Schaik Carel
Department of Physics, University of South Florida, Tampa, Florida, United States of America.
Anthropological Institute & Museum, University of Zurich, Zurich, Switzerland.
PLoS One. 2017 Dec 11;12(12):e0188970. doi: 10.1371/journal.pone.0188970. eCollection 2017.
In order to predict the features of non-raiding human warfare in small-scale, socially stratified societies, we study a coalitionary model of war that assumes that individuals participate voluntarily because their decisions serve to maximize fitness. Individual males join the coalition if war results in a net economic and thus fitness benefit. Within the model, viable offensive war ensues if the attacking coalition of males can overpower the defending coalition. We assume that the two groups will eventually fuse after a victory, with ranks arranged according to the fighting abilities of all males and that the new group will adopt the winning group's skew in fitness payoffs. We ask whether asymmetries in skew, group size and the amount of resources controlled by a group affect the likelihood of successful war. The model shows, other things being equal, that (i) egalitarian groups are more likely to defeat their more despotic enemies, even when these are stronger, (ii) defection to enemy groups will be rare, unless the attacked group is far more despotic than the attacking one, and (iii) genocidal war is likely under a variety of conditions, in particular when the group under attack is more egalitarian. This simple optimality model accords with several empirically observed correlations in human warfare. Its success underlines the important role of egalitarianism in warfare.
为了预测小规模、社会分层社会中非掠夺性人类战争的特征，我们研究了一种战争联盟模型，该模型假设个体自愿参与，因为他们的决策旨在使适应性最大化。如果战争能带来净经济收益从而带来适应性益处，个体男性就会加入联盟。在模型中，如果男性攻击联盟能够击败防御联盟，就会引发可行的进攻性战争。我们假设两组最终会在胜利后融合，根据所有男性的战斗能力排列等级，并且新群体将采用获胜群体在适应性收益方面的倾斜度。我们询问倾斜度、群体规模和群体控制的资源量方面的不对称性是否会影响成功战争的可能性。该模型表明，在其他条件相同的情况下，（i）平等主义群体更有可能击败其更专制的敌人,即使这些敌人更强大；（ii）叛逃到敌对阵营的情况很少见，除非被攻击群体比攻击群体专制得多；（iii）种族灭绝战争在各种情况下都有可能发生，特别是当被攻击群体更加平等主义时。这个简单的最优性模型与人类战争中一些实证观察到的相关性相符。它取得的成功凸显了平等主义在战争中的重要作用。
