The Origins of War: The Evolution of Intergroup Violence in Animals and Man

1. The Origins of War:The Evolution of Intergroup Violence in Animals and Man Based on: The Origin of War: The Evolution of a Male-Coalitional Reproductive Strategy Johan M.G. van der Dennen

2. The Origins of War • What this presentation is not about:

3. The Origins of War • What this presentation is not about: • Hypertrophy of aggression

4. The Origins of War • What this presentation is not about: • Hypertropy of aggression • Aggression instincts

5. The Origins of War • What this presentation is not about: • Hypertrophy of aggression • Aggression instincts • ‘Todestrieb’ or other destructive inclinations

6. The Origins of War • What this presentation is not about: • Hypertrophy of aggression • Aggression instincts • ‘Todestrieb’ or other destructive inclinations • Innate belligerence or bellicosity

7. The Origins of War • What this presentation is not about: • Hypertrophy of aggression • Aggression instincts • ‘Todestrieb’ or other destructive inclinations • Innate belligerence or bellicosity • ‘Evil’ or malicious/malevolent Man(kind)

8. The Origins of War • What this presentation is not about: • Hypertrophy of aggression • Aggression instincts • ‘Todestrieb’ or other destructive inclinations • Innate belligerence or bellicosity • ‘Evil’ or malicious/malevolent Man(kind) • These are only quasi-explanations of human behavior

9. The Origins of War • War as a unique one-time cultural invention

10. The Origins of War • War as a unique one-time cultural invention

11. The Origins of War • War as a unique one-time cultural invention This picture from Australia’s ‘Kakadu National Park’ is at least ten thousand years old.

12. The Origins of War • War as a unique one-time cultural invention This picture from Australia’s ‘Kakadu National Park’ is at least ten thousand years old. But are these hunters or warriors?

13. The Origins of War • War as a unique one-time cultural invention This picture from Australia’s ‘Kakadu National Park’ is at least ten thousand years old. But are these hunters or warriors? Does a hunter need a shield?

14. The Origins of War • or phylogenetic (evolutionary) continuity?

15. The Origins of War • or phylogenetic (evolutionary) continuity? From altercations and skirmishes between animal territorial groups

16. The Origins of War • or phylogenetic (evolutionary) continuity? Via violent conflicts between preindustrial (nonstate) societies

17. The Origins of War • or phylogenetic (evolutionary) continuity? Until ‘real’ wars between city-states, states, and empires

18. The Origins of War • or phylogenetic (evolutionary) continuity? From altercations and skirmishes between animal territorial groups Via violent conflicts between preindustrial (nonstate) societies Until ‘real’ wars between city-states, states, and empires

19. The Origins of War • Three central problems:

20. The Origins of War • Three central problems: • Why war in only so few organisms?

21. The Origins of War • Three central problems: • Why war in only so few organisms? • Why this absence of intergroup competition?

22. The Origins of War • Three central problems: • Why war in only so few organisms? • Why this absence of intergroup competition? • Why only males as warriors or soldiers?

23. The Origins of War • Three central problems: • Why war in only so few organisms? • Why this absence of intergroup competition? • Why only males as warriors or soldiers? • Plus two proximate-level questions:

24. The Origins of War • Three central problems: • Why war in only so few organisms? • Why this absence of intergroup competition? • Why only males as warriors or soldiers? • Plus two proximate-level questions: • War causation (Why are particular wars waged?)

25. The Origins of War • Three central problems: • Why war in only so few organisms? • Why this absence of intergroup competition? • Why only males as warriors or soldiers? • Plus two proximate-level questions: • War causation (Why are particular wars waged?) • Combat motivation (Why do males fight?)

26. The Origins of War • The principal thesis of my evolutionary scenario (evolutionario):War originated as the result of enhanced (polyadic, coalitional) cooperation between (a number of) males within groups for the purpose of violent competition between groups for females and territory (or territory and the females – and other resources – on it).

27. The Origins of War • Alternatively, Wrangham (1999) presents his adaptive hypothesis for explaining the species distribution of intergroup coalitional killing. This is the Imbalance-of-Power Hypothesis, which suggests that coalitional killing is the expression of a drive for dominance over neighbors.

28. The Origins of War • Two conditions are proposed to be both necessary and sufficient to account for coalitional killing of neighbors: (1) a state of intergroup hostility; (2) sufficient imbalances of power between parties that one party can attack the other with impunity. Under these conditions, it is suggested, selection favors the tendency to hunt and kill rivals when the costs are sufficiently low.

29. The Origins of War • But whether for territory/females or intergroup dominance (which do not exclude each other anyway), warring behavior may be considered to be a strategy which, as all other behaviors, originated and developed in the course of evolution for the optimation of reproductive success.

30. The Origins of War

31. The Origins of War • Even if it looks like males (individual or in coalitions) are fighting only for dominance or territorial expansion, the underlying rationale is the lifelong attempt to enhance their chances of reproductive success through monopolization of one or more females, or increased access to females (via subtle, sneaky, or aggressive/violent tactics).

32. The Origins of War • In social carnivores and primates it is the females who form the stable social group-territorial core. They live in family groups of related females and their offspring. They benefit most from the integrity or expansion of the group territory; they have the most to lose. But because their aim is ‘only’ the strategic retreat of the other group – and not reproductive success – their willingness to incur injuries or even death is very slight.

33. The Origins of War • Two principal modes or forms of intergroup antagonism:

34. The Origins of War • Two principal modes or forms of intergroup antagonism: • The (pitched) battle or combat (in humans often ritualized to a large extent)

35. The Origins of War These are some examples of battle or combat in humans. Above: The Dani (New Guinea). Below: thephalanx – the greatest invention in the history of ‘civilized’ warfare.

36. The Origins of War • Two principal modes or forms of intergroup antagonism : • The (pitched) battle or combat (in humans often ritualized to a large extent) • The raid or ambush (lethal male raiding) (only to be found in humans [universally] and chimpanzees [at least in some populations] – and much more lethal than the battles through small but rapidly accumulating casualties)

37. Example of lethal male raiding by Timucua (Florida) Indians (de Bry, ± 1590). This is the archetypical raid; note the incendiary arrows.

38. The Origins of War Intergroup antagonism in female macaques (Macaca mulatta). Please observe the two combat lines (battle arrays).

39. The Origins of War

40. The Origins of War • In only two known species (Homo sapiens and Pan troglodytes) it is the males who use coalitional violence – but then cold-blooded and level-headed. Male chimps go ‘on patrol’ to penetrate into the territory of ‘the enemy’ and attack numerically weaker foraging parties – and severely maul and mortally injure their hapless victims. Their behavior looks very deliberate, purposeful and intentional - like a guerrilla operation.

41. The Origins of War Two Kasakela males inspect the territory of ‘the enemy’. Observe the contrast with the excited and vociferous behavior of the macaque females.

42. The Origins of War Here is another example of chimpanzee males going ‘on patrol’ intentionally and apparently in cold-blood. They look startled and alert rather than aggressive or angry.

43. The Origins of War • The insufficiently explained phenomenon of female migration between groups (or male philopatry) in the HUCHIBO (HUmans, CHImps, BOnobos [Pan paniscus]) clade...

44. The Origins of War • ... is allegedly responsible for the origin and evolution of a specific male psychology of (polyadic) coalition formation. This ‘coalitional psychology’ probably evolved initially through kin selection. A within-group coalition of cooperating and concertedly operating males is an eminent and superb instrument in the competition between groups for resources. For the reproductive success of males females are the ‘ultimate’ limiting resource.

45. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been:

46. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been: • the ability to cooperate and form coalitions

47. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been: • the ability to cooperate and form coalitions • Kin selection (inclusive fitness, nepotism) (Hamilton) • Reciprocal altruism (reciprocity) (Trivers) • The ‘risk-contract’ theory of coalitions (Tooby & Cosmides)

48. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been: • the ability to cooperate and form coalitions • a certain amount of ethnocentrism

49. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been: • the ability to cooperate and form coalitions • a certain amount of ethnocentrism • a high degree of social intelligence

50. The Origins of War • Necessary conditions for the origin and evolution of war in the protohistory of the human species have been: • the ability to cooperate and form coalitions • a certain amount of ethnocentrism • a high degree of social intelligence • ‘theory of mind’; Machiavellian intelligence (suggesting malicious manipulation) or, more neutrally, ‘strategic’ intelligence