Warfare in an evolutionary perspective

Abstract

The importance of warfare for human evolution is hotly debated in anthropology. Some authors hypothesize that warfare emerged at least 200,000–100,000 years BP, was frequent, and significantly shaped human social evolution. Other authors claim that warfare is a recent phenomenon, linked to the emergence of agriculture, and mostly explained by cultural rather than evolutionary forces. Here I highlight and critically evaluate six controversial points on the evolutionary bases of warfare. I argue that cultural and evolutionary explanations on the emergence of warfare are not alternative but analyze biological diversity at two distinct levels. An evolved propensity to act aggressively toward outgroup individuals may emerge irrespective of whether warfare appeared early/late during human evolution. Finally, I argue that lethal violence and aggression toward outgroup individuals are two linked but distinct phenomena, and that war and peace are complementary and should not always be treated as two mutually exclusive behavioral responses.

Philosophical Questions and Biological Findings, Part I: Human Cooperativity, Competition, and Aggression

“…In their important overview of the literature, Kissel and Kim write, “we propose that emergent warfare would have been part of a suite of human behavioral patterns as early as 200–300 kya” (2019, 157). Other overviews of the research include Majolo (2019), Luke Glowacki, Michael Wilson, and Wrangham (2017), Raymond Kelly (2000), Keith Otterbein (2004, 2009), and Wrangham (1999). Important research arguing specifically for the “Adam” view includes, Mark Allen (2014), Samuel Bowles (2009), Azar Gat (2015), Mark Golitko and Lawrence Keeley (2007), Steven LeBlanc (2014), and Steven Pinker (2011).…”

“…Yet, Wrangham notes of hunter‐gatherer raiding, “proactive aggression is successful when it involved attacking at low risk of being hurt” (2019, 262). Majolo also finds that, “humans are likely to be aggressive toward outgroup individuals under some specific ecological conditions but display lethal violence only when the risk of such violence is low” (2019, 327). Cooperation or at least nonengagement may be the more productive approach.…”

“…Matthew Zefferman and Sarah Mathew note the “transition from low‐risk, small‐scale territorial raiding to high‐risk, large‐scale warfare,” which they hold is culturally prodded. Bonaventura Majolo holds that human development was likely spurred by both cultural and genetic adaptations (2019, 323). This study concurs and adds only those ecological and resource conditions that too influenced the practice of aggression.…”

“…While the capacity for aggression may be hundreds of thousands of years old, as Kissel, Kim, and Majolo note, evidence of occurrence of severe, systemic aggression before the mid‐Holocene is rare (Majolo 2019, 322). Several explanations have been proposed: (i) severe, systemic aggression was prevalent before the mid‐Holocene but we have not yet found evidence of it; (ii) severe, systemic aggression gradually increased during the hunter‐gatherer period but we have not yet found evidence of the increase; (iii) severe, systemic aggression did not occur among hunter‐gatherers of the Mesopotamian, Mediterranean, and certain African regions at rates similar to those among later agriculturalists.…”

Evolutionary and Life History Insights into Masculinity and Warfare

“…Chimpanzees and other organisms have been suggested to engage in warfare and lethal conspecific violence (Gomez et al 2016). But within historical times, no other species has employed war on the scale, complexity, or lethality as humans (Glowacki, Wilson, and Wrangham 2017;Majolo 2019;Wrangham 1999;Wrangham and Peterson 1996). Indeed, modern human warfare threatens not only all people but the viability of all life on the entire planet (Ehrlich et al 1983).…”