Warfare and the Evolution of Social Complexity

1. Warfare and the Evolution of Social Complexity Peter Turchin University of Connecticut talk at UC Riverside, Feb. 2009

2. August 1914. Outbreak of World War I. • All over Europe patriotic crowds demonstrate in support of war • 750,000 British men volunteer in August and September • Total war deaths: 8.5 million Odeon Platz, Munich 2 Aug. 1914

3. Why are humans willing to sacrifice for the sake of whole societies? • Ultrasociality – extensive cooperation among very large numbers of genetically unrelated individuals • a unique feature of humans • a challenge to the evolutionary theory • cannot be explained by • kin selection • reciprocal altruism • The Theory of Multilevel Selection • D.S. Wilson, Boyd & Richerson, Bowles

4. Evolution of human sociality by multilevel selection A rapidly maturing theory for the evolution of small-scale sociality groups of up to 100-200 people Ultimate mechanism: multilevel selection “Selfishness beats altruism within groups. Altruistic groups beat selfish groups” (Wilson and Wilson 2007) Proximate factors egalitarianism, levelling mechanisms, inequity aversion: reduce intragroup variance in fitness moralistic punishment stabilizes cooperation intergroup competition/conflict: warfare

5. Cooperation as a glue of society • The “nonobvious sociological insight” • (Collins 1992) • Emile Durkheim (1858-1917) • Ibn Khaldun (1332-1406) • Asabiya: • capacity of a group for collective action • need a theory for the dynamics of asabiya • why it increases and why decreases

6. Warfare: the Selective Force • A Human Universal • apes do it • small-scale societies do it • states do it Neolithic cave painting of battle between two groups of archers Morella la Villa, Spain

7. Why War? • Ultimate causation • pacifist groups are eliminated by warlike groups • Proximate mechanisms • Competition for scarce resources • territory (hunting grounds, cropland) • females, slaves, livestock • booty (portable wealth) • Strategic calculations • Revenge: retaliation to eliminate/deter enemies • The “security dilemma”: expectation of an impending conflict leads to a preemptive attack

8. Percentage of male deaths due to warfare (Keeley 1996)

9. Evolutionary responses to warfare Increasing group solidarity/cohesion Development of new technologies military administrative ideological (religion, social prestige) Increasing the size of the cooperating group “God favors the big battalions” The “Social Brain” hypothesis

10. Summary so far • We have good beginnings of a theory for the evolution of small-scale sociality • But how did large-scale societies evolve? • How did evolution break through the limits imposed by face-to-face sociality?

11. The Plan • A theory for the evolution of large-scale societies on metaethnic frontiers • An empirical test: the association between nomadic/farmer frontiers and empire size in historical record • The European/Native frontier in North America

12. Large-scale human societies • size: up to tens/hundreds of million people • stratified (inegalitarian) • complex: many hierarchical (nested) levels • organized: as states

13. A mechanism for the social scaling-up process A binary relationship: lord-vassal chiefly village/subordinate village An elementary building block for constructing hierarchical social nets

14. Adding hierarchical levels allows building social networks of practically unlimited size

15. Hierarchical social organization allows to increase group size without increasing social channel capacity but there is a downside: it inevitably leads to inegalitarian societies there must be a compelling reason for this innovation to be adopted A hypothesis: evolution of social complexity should be favored where (when) warfare is particularly intense

16. Metaethnic frontiers A metaethnic community: the largest-scale (supranational) grouping of peoples Latin Christendom Dar al Islam Turco-Mongolian nomadic pastoralists Metaethnic frontiers: where warfare tends to be particularly intense Sharp cultural boundaries demarcated with symbolic markers Large cultural distance makes it easier to dehumanize the adversary

17. Darfur: Genesis of a Genocide • Failure of the state to impose peace/order • From 1982-4: a severe drought • Plains used by the nomads were worst hit • The nomads migrated towards the hill region, inhabited by farmers (greater rainfall) • Conflict between farmers and nomads • Nomads created an alliance against the farmers (Janjaweed), raided villages • Farmers created their own defensive alliance and allied with the SPLA • The government began supporting Janjaweed

18. Metaethnic Frontiers • civilizational faultlines (a la Huntington) • example: Iberian Muslim/Christian frontier • “civilization”/”barbarism” frontier • example: Mediterranean civilization/”barbarian” Celts • steppe frontiers between nomadic pastoralists and settled agriculturalists • tend to be the most intense kind

19. Steppe Frontiers anisotropy in military power especially since the invention of mounted archery (~IX c. BC) carbohydrate deficiency of pastoralist economy huge difference in the way of life and culture demonization of the other

20. A prediction: largest states should be found at interfaces between settled and nomadic societies • Database: largest territorial polities • excluding modern sea-based empires • Source: Taagepera, Chase-Dunn, et al • Cut-off point: territory ≥ 1 Mm2 (=106 km2) at peak • More than 60 such polities are known • only 1 (Inca) outside Afroeurasia

21. Lith-Pol Russia Frank GoldenH Kiev Huns Khazar Mongol Manchu Khorezm Chagatai Byz Juan Liao Rom Jur Timur Osman Kara-Kh Hsi Turk Parth Assyr Liang Sele Selj Med Ghazn Hsnu Shang Almorav Caliph Sam Buy Ayy Uig Han Tang Sas Kushan Fatim Il-Kh Mam Tufan Mughal Ming Ach Sung Maur Delhi Gupta Egypt Harsha Almohad Mar Mali Axum Khmer M

22. The East Asian Imperiogenesis Hotspot: Empirical Patterns • 14 unifications of China from the Shang to Communist eras (some partial) • (E.N. Anderson, supplemented) • Summary: • 8 unifications from NW (usually, Wei RV) • 3 unifications from NE (Liao, Manchuria) • 2 unifications from NC (Huang He) • 1 unification from SC (Nanjing)

23. Imperiogenesis in South Asia: Empirical Patterns Northwest (Afghanistan) 5 North (the Gangetic plain) 3 West (western Deccan) 1 Northeast (Bengal and Assam) − Central India − Southern India −

24. Unifications of Egypt by Native Dynasties

26. Religion as an integrative ideology Axial age ideologies enabled cooperation at a very large scale, beyond ethnic communities Monotheism Buddhism Confucianism Stoicism The key is not the supernatural, but the integrative aspect Latin religio = bond

27. Another example: the United States • A highly cooperative society • exceptional ability for voluntary association (de Tocqueville) • abundance of social capital (Putnam) • The melting pot • “e pluribus unum”

28. European Settlers and Indians • A “civilization-barbarism” frontier • almost three centuries long • Very intense, sometimes genocidal intensity of conflict • torture, mutual atrocities (16,000 recorded) • Casualties in some American wars • First Powhatan War: 30% • Second Powhatan War: 6% • King Philip’s War: 2% • World War I: 0.1% • World War II: 0.3%

29. “The Whites”: Pennsylvania, c.1740(Silver, 2008. Our Savage Neighbors) Quakers Anglicans Irish Presbyterians Scottish Covenanters German Lutherans Moravians Mennonites, Schwenkfelders, etc “Pennsylvania is a compleat Babel”

30. Civic Organizations and Indian Wars 1740s: Appearance of ethnically and denominationally based clubs St. Andrews Society Deutsche Gesellschaft 1760s: focus shifts to charity for the victims of Indian attacks first, directed at the narrow group later, the definition of “us” expanded eventually included all “white people”

31. Conclusions • Warfare is ubiquitous but not constant • It is particularly intense where culturally very different groups are in contact and conflict • metaethnic (esp., steppe) frontiers • Empirical evidence: a strong association between metaethnic frontiers and formation of the largest empires