States in Mind: Evolution, coalitional psychology, and international politics

International Security

Volumn 36, Issue 2, 2011, Pages 48-83

  Lopez, Anthony C ^a   McDermott, Rose ^a   Petersen, Michael Bang ^b  

^a BROWN UNIVERSITY   (United States)

^b AARHUS UNIVERSITY   (Denmark)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 84856425428     PISSN: 01622889     EISSN: 15314804     Source Type: Journal    
DOI: 10.1162/ISEC_a_00056     Document Type: Article

References (170)

1. J.R. Alford and J.R. Hibbing, "The Origin of Politics: An Evolutionary Theory of Political Behavior," Perspectives on Politics, Vol. 2, No. 4 (December 2004), pp. 707-723.
2. B.A. Thayer, "Bringing in Darwin: Evolutionary Theory, Realism, and International Politics," International Security, Vol. 25, No. 2 (Fall 2000), pp. 124-151.
3. D.S.A. Bell and P.K. MacDonald, "Correspondence: Start the Evolution without Us," International Security, Vol. 26, No. 1 (Summer 2001), pp. 187-194.
4. J. Tooby, L. Cosmides, and M.E. Price, "Cognitive Adaptations for n-Person Exchange: The Evolutionary Roots of Organizational Behavior," Managerial and Decision Economics, Vol. 27, Nos. 2-3 (March-May 2006), pp. 103-129.
5. A. Gat,War in Human Civilization (Oxford: Oxford University Press, 2006).
6. C. Boehm, Hierarchy in the Forest: The Evolution of Egalitarian Behavior (Cambridge, Mass.: Harvard University Press, 1999).
7. M. E. Price, L. Cosmides, and J. Tooby, "Punitive Sentiment as an Anti-Free Rider Psychological Device," Evolution and Human Behavior, Vol. 23, No. 3 (May 2002), pp. 203-231.
8. S. Pinker, How the Mind Works (New York: W.W. Norton, 1997).
9. R,W. Wrangham, "Evolution of Coalitionary Killing," Yearbook of Physical Anthropology, Vol. 42 (1999), pp. 1-30.
10. L. Cosmides and J. Tooby, "From Evolution to Behavior: Evolutionary Psychology as the Missing Link," in John Dupré, ed., The Latest on the Best: Essays on Evolution and Optimality Cambridge, Mass.: MIT Press, 1987), pp. 276-306.
11. Jerome H. Barkow, Leda Cosmides, and John Tooby, eds., The Adapted Mind: Evolutionary Psychology and the Generation of Culture (New York: Oxford University Press, 1992).
12. David M. Buss, ed., The Handbook of Evolutionary Psychology (Hoboken, N.J.: John Wiley and Sons, 2005).
13. Our discussion of evolutionary psychology follows the adaptationist approach of evolutionary biology's "modern synthesis."
14. See George C.Williams, Adaptation and Natural Selection: A Critique of Some Current Evolutionary Thought (Princeton, N.J.: Princeton University Press, 1966).
15. Ernst Mayr, "How to Carry Out the Adaptationist Program?" American Naturalist, Vol. 121, No. 3 (March 1983), pp. 324-334.
16. Lawrence H. Keeley, War before Civilization: The Myth of the Peaceful Savage (New York: Oxford University Press, 1996).
17. Keith F. Otterbein, "The Origins of War," Critical Review, Vol. 11, No. 2 (Spring 1997), pp. 251-277.
18. Azar Gat, "The Human Motivational Complex: Evolutionary Theory and the Causes of Hunter-Gatherer Fighting, Pt. 1: Primary Somatic and Reproductive Causes," Anthropological Quarterly, Vol. 73, No. 1 (January 2000), pp. 20-34.
19. Steven A. LeBlanc and Katherine E. Register, Constant Battles: The Myth of the Peaceful, Noble Savage (New York: St. Martin's, 2003).
20. John Tooby and Leda Cosmides, "The Evolution of War and Its Cognitive Foundations," Technical Report, No. 88-1 (Santa Barbara: Institute for Evolutionary Studies, University of California, Santa Barbara, 1988).
21. Richard W. Wrangham, "Is Military Incompetence Adaptive?" Evolution and Human Behavior, Vol. 20, No. 1 (January 1999), pp. 3-17.
22. John D. Wagner, Mark V. Flinn, and Barry G. England, "Hormonal Response to Competition among Male Coalitions," Evolution and Human Behavior, Vol. 23, No. 6 (November 2002), pp. 437-442.
23. Dominic D.P. Johnson, Rose McDermott, Emily S. Barrett, Jonathan Cowden, Richard W. Wrangham, Matthew H. McIntyre, and Stephen Peter Rosen, "Overconfidence in Wargames: Experimental Evidence on Expectations, Aggression, Gender, and Testosterone," Proceedings of the Royal Society B, June 20, 2006, pp. 2513-2520.
24. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange"
25. Geoff A. Parker, "Assessment Strategy and Evolution of Fighting Behavior," Journal of Theoretical Biology, Vol. 47, No. 1 (September 1974), pp. 223-243.
26. John Archer, The Behavioural Biology of Aggression (Cambridge: Cambridge University Press, 1988).
27. Aaron Sell, John Tooby, and Leda Cosmides, "Formidability and the Logic of Human Anger," Proceedings of the National Academy of Sciences, Vol. 106, No. 35 (September 2009), pp. 15073-15078.
28. Leda Cosmides and John Tooby, "Origins of Domain Specificity: The Evolution of Functional Organization," in Lawrence A. Hirshfeld and Susan A. Gelman, eds., Mapping the Mind: Domain Specificity in Cognition and Culture (New York: Cambridge University Press, 1994), pp. 85-116.
29. Importantly, there is much theoretical debate about the extent of domain specificity that is characteristic of evolved psychological mechanisms. Many evolutionary psychologists acknowledge that in addition to the array of highly domain-specific adaptations in the brain, selection also could have favored certain domain-general mechanisms to deal with novel environmental challenges. Nevertheless, this debate distracts from the underlying agreement among scholars about the design of adaptations, which is our basic point: the ultimate constraint on the design of a biological adaptation is the selection pressure that favored its emergence. Therefore, it is often more precise for analysis to be driven by the question: How does an adaptation represent an efficient solution to a particular reproductive challenge? It is the causal link between selection pressures and the adaptations they shape that is important, not a priori attachments to an arbitrary level of speci ficity or generality. But because in a real sense there is no such thing as a "general" problem that an organism confronts, the convention among evolutionary theorists is to view adaptations as specialized solutions to specific reproductive challenges.
30. See Dan Chiappe and Kevin MacDonald, "The Evolution of Domain-General Mechanisms in Intelligence and Learning," Journal of General Psychology, Vol. 132, No. 1 (January 2005), pp. 5-40.
31. H. Clark Barrett, Leda Cosmides, and John Tooby, "The Hominid Entry into the Cognitive Niche," in Steven W. Gangstead and Jeffry A. Simpson, eds., The Evolution of Mind: Fundamental Questions and Controversies (New York: Guilford, 2007), pp. 241-248.
32. Randolph M. Nesse, "Evolutionary Explanations of Emotions," Human Nature, Vol. 1, No. 3 (1990), pp. 261-289.
33. Leda Cosmides and John Tooby, "Evolutionary Psychology and the Emotions," in Michael Lewis and Jeanette M. Haviland-Jones, eds., Handbook of the Emotions, 2d ed. (New York: Guilford, 2000), pp. 91-115.
34. It should be noted that the better-known approach of behavior genetics is to be distinguished from evolutionary psychology, which we focus on here. Although both approaches investigate the biological bases of behavior, the questions they ask are fundamentally different. Behavior genetics and related methods explain behavioral variation as a consequence of underlying genetic differences among individuals in a population. An adaptationist approach such as evolutionary psychology, however, explains behavior as the functional output of a species-typical evolved psychology interacting with variable internal and external environments. The latter, which we focus on in this article, has received less attention in political science generally.
35. John Tooby and Leda Cosmides, "The Psychological Foundations of Culture," in Barkow, Cosmides, and Tooby, The Adapted Mind, pp. 19-136.
36. David M. Buss, Evolutionary Psychology: The New Science of the Mind, 2d ed. (Boston: Allyn and Bacon, 2004).
37. John Tooby and Irven DeVore, "The Reconstruction of Hominid Behavioral Evolution through Strategic Modeling," in Warren G. Kinzey, ed., The Evolution of Human Behavior: Primate Models (Albany: State University of New York Press, 1987), chap. 10.
38. Parker, "Assessment Strategy and Evolution of Fighting Behavior"
39. Archer, The Behavioural Biology of Aggression.
40. Aaron Sell, Leda Cosmides, John Tooby, Daniel Sznycer, Christopher von Rueden, and Michael Gurven, "Human Adaptations for the Visual Assessment of Strength and Fighting Ability from the Body and Face," Proceedings of the Royal Society B, February 2009, pp. 575-584.
41. Aaron Sell, Gregory A. Bryant, Leda Cosmides, John Tooby, Daniel Sznycer, Christopher von Reuden, Andre Krauss, and Michael Gurven, "Adaptations in Humans for Assessing Physical Strength from the Voice," Proceedings of the Royal Society B, June 2010, pp. 3509-3518.
42. Richard Wrangham and Dale Peterson, Demonic Males: Apes and the Origins of Human Violence (Boston: Houghton Mifflin, 1996).
43. Wrangham, "Evolution of Coalitionary Killing"
44. Charles R. Gallistel, The Organization of Learning (Cambridge, Mass.: MIT Press, 1990).
45. Dan Sperber, Explaining Culture: A Naturalistic Approach (Oxford: Blackwell, 1996).
46. Donald Symons, "On the Use and Misuse of Darwinism in the Study of Human Behavior," in Barkow, Cosmides, and Tooby, The Adapted Mind, pp. 137-162.
47. Michael Bang Petersen, "Public Opinion and Evolved Heuristics: The Role of Category-Based Inference," Journal of Cognition and Culture, Vol. 9, No. 3 (2009), pp. 367-389.
48. Duncan Bell, "Beware of False Prophets: Biology, Human Nature, and the Future of International Relations Theory," International Affairs, Vol. 82, No. 3 (May 2006), p. 504.
49. Thayer, "Bringing in Darwin"
50. Bell and MacDonald, "Correspondence: Start the Evolution without Us," p. 192.
51. Thayer, "Bringing in Darwin," p. 125.
52. Alford and Hibbing, "The Origin of Politics," p. 709.
53. Robert Axelrod and William D. Hamilton, "The Evolution of Cooperation," Science, March 27, 1981, pp. 1390-1396.
54. Leda Cosmides and John Tooby, "Neurocognitive Adaptations Designed for Social Exchange," in Buss, The Handbook of Evolutionary Psychology, chap. 20.
55. Price, Cosmides, and Tooby, "Punitive Sentiment as an Anti-Free Rider Psychological Device."
56. John Orbell, Tomonori Morikawa, Jason Hartwig, James Hanley, and Nicholas Allen, "'Machiavellian' Intelligence as a Basis for the Evolution of Cooperative Dispositions," American Political Science Review, Vol. 98, No. 1 (February 2004), pp. 1-15.
57. Azar Gat, "The Causes and Origins of 'Primitive Warfare': Reply to Ferguson," Anthropological Quarterly, Vol. 73, No. 3 (July 2000), p. 167 (emphasis in original).
58. The distinction between proximate and ultimate evolutionary explanations comes from Niko Tinbergen, "On Aims and Methods of Ethology," Animal Biology, Vol. 55, No. 4 (December 2005), pp. 297-321.
59. Michael Scriven, "Explanation and Prediction in Evolutionary Theory," Science, August 28, 1959, pp. 477-482.
60. Robert Henry Peters, "Letter to the Editors: Predictable Problems with Tautology in Evolution and Ecology," American Naturalist, Vol. 112, No. 986 (July-August 1978), pp. 759-762.
61. In a general sense, there are two major sources of behavioral variability. The first is outlined exclusively in this article, in which we describe behavior as the contingent product of the interaction of evolved information-processing systems with their internal and external environments. In other words, variation in behavior is explained largely as a consequence of universal psychological mechanisms interacting with variable environments. Asecond type of explanation is often provided by approaches that examine those sets of biological features that are not universal and not designed by natural selection, but are found in some individuals and not in others as a consequence of other evolutionary processes, such as genetic mutation and drift. An example would be variation in the presence of a particular gene or "allele" throughout a population, which corresponds to variation in some phenotypic trait, such as aggressiveness. Although these two sources of variability are distinct, they are not irreconcilable.
62. For an elaboration of these approaches, see John Tooby and Leda Cosmides, "On the Universality of Human Nature and the Uniqueness of the Individual: The Role of Genetics and Adaptation," Journal of Personality, Vol. 58, No. 1 (March 1990), pp. 17-67.
63. David M. Buss and Heidi Greiling, "Adaptive Individual Differences," Journal of Personality, Vol. 67, No. 2 (April 1999), pp. 209-243.
64. Anthony C. Lopez and Rose McDermott, "Adaptation, Heritability, and the Emergence of Evolutionary Political Science," Political Psychology, forthcoming.
65. Note that we do not inquire into the present-day adaptiveness of any particular trait or feature. Whether a trait is adaptive in modern environments is not an indicator that it was designed by natural selection in the past, and it is therefore not an indicator that the trait in question is an adaptation. In addition, we avoid the "naturalistic fallacy" by recognizing that the mere fact that a trait or system was favored by selection does not mean that this trait or system is normatively "good" in a moral or ethical sense.
66. Bruce Bueno de Mesquita, "The Benefits of a Social-Scientific Approach to Studying International Affairs," in Ngaire Woods, ed., Explaining International Relations since 1945 (New York: Oxford University Press, 1996), p. 58.
67. Angus Campbell, Philip E. Converse, Warren E. Miller, and Donald E. Stokes, The American Voter (New York: John Wiley and Sons, 1960).
68. Alexander Wendt, "The State as Person in International Theory," Review of International Studies, Vol. 30, No. 2 (April 2004), pp. 289-316.
69. Robert G. Gilpin, "The Richness of the Tradition of Political Realism," International Organization, Vol. 38, No. 2 (Spring 1984), p. 44.
70. Robert L. Kelly, The Foraging Spectrum: Diversity in Hunter-Gatherer Lifeways (Washington, D.C.: Smithsonian Institution Press, 1995).
71. Christopher Boehm, "Conflict and the Evolution of Social Control," Journal of Consciousness Studies, Vol. 7, Nos. 1-2 (2000), pp. 79-101.
72. Mark van Vugt and Rob Kurzban, "Cogntive and Social Adaptations for Leadership and Followership: Evolutionary Game Theory and Group Dynamics," in Joseph P. Forgas, Martie G. Haselton, and William von Hippel, eds., Evolution and the Social Mind: Evolutionary Psychology and Social Cognition (New York: Psychology Press, 2007), chap. 14.
73. Joey T. Cheng, Jessica L. Tracy, and Joseph Henrich, "Pride, Personality, and the Evolutionary Foundations of Human Social Status," Evolution and Human Behavior, Vol. 31, No. 5 (September 2010), p. 334.
74. Phyllis C. Lee, "Evolution and Ecological Diversity in Animal Mating and Parenting Systems," in Peter T. Ellison and Peter B. Gray, eds., Endocrinology of Social Relationships (Cambridge, Mass.: Harvard University Press, 2009), p. 21.
75. Kelly, The Foraging Spectrum.
76. Robert Boyd and Joan B. Silk, How Humans Evolved, 5th ed. (New York:W.W. Norton, 2009).
77. Wrangham and Peterson, Demonic Males.
78. Martin Daly and Margo Wilson, Homicide (New York: Aldine de Gruyter, 1988).
79. Wrangham, "Evolution of Coalitionary Killing."
80. Keeley, War before Civilization; LeBlanc and Register, Constant Battles.
81. Gat, War in Human Civlization.
82. Joseph H. Manson and Richard W. Wrangham, "Intergroup Aggression in Chimpanzees and Humans," Current Anthropology, Vol. 32, No. 4 (August-October 1991), pp. 369-390.
83. Tooby and Cosmides, "The Evolution of War and Its Cognitive Foundations"
84. Gat, "The Human Motivational Complex."
85. Forgas, Haselton, and Hippel, Evolution and the Social Mind.
86. Mark Schaller, Jeffry A. Simpson, and Douglas T. Kenrick, eds., Evolution and Social Psychology (New York: Psychology Press, 2006).
87. Tooby and Cosmides, "The Evolution of War and Its Cognitive Foundations"
88. Frans B.M. de Waal and Alexander H. Harcourt, "Coalitions and Alliances: A History of Ethological Research," in deWaal and Harcourt, eds., Coalitions and Alliances in Humans and Other Animals (New York: Oxford University Press, 1992), chap. 1.
89. Lee Alan Dugatkin, Cooperation among Animals: An Evolutionary Perspective (New York: Oxford University Press, 1997).
90. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange."
91. De Waal and Harcourt, "Coalitions and Alliances." The choice of the label "coalitional" psychology is favored because it is the convention among evolutionary psychologists. See Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange." Note that many of the claims we will make about coalitional psychology will be specific to coalitions, per se, and not alliances, or vice versa. It is an empirical question, however, whether and to what extent the structure of evolved mechanisms designed to navigate coalitions differs from those designed to navigate alliances. We leave this as an open and important empirical question for future research in international relations.
92. Robert Kurzban, John Tooby, and Leda Cosmides, "Can Race Be Erased? Coalitional Computation and Social Categorization," Proceedings of the National Academy of Sciences, December 18, 2001, pp. 15387-15392.
93. Leda Cosmides, John Tooby, and Robert Kurzban, "Perceptions of Race," Trends in Cognitive Sciences, Vol. 7, No. 4 (April 2003), pp. 173-179.
94. Francisco J. Gil-White, "Are Ethnic Groups Biological 'Species' to the Human Brain?" Current Anthropology, Vol. 42, No. 4 (August-October 2001), pp. 515-554.
95. Lawrence A. Hirschfeld, "On a Folk Theory of Society: Children, Evolution, and Mental Representations of Social Groups," Personality and Social Psychology Review, Vol. 5, No. 2 (2001), pp. 107-117.
96. and Robert Kurzban and Steven Neuberg, "Managing Ingroup and Outgroup Relationships," in Buss, The Handbook of Evolutionary Psychology, chap. 22.
97. Robert M. Sapolsky, "A Natural History of Peace," Foreign Affairs, Vol. 85, No. 1 (January/February 2006), pp. 104-120.
98. In international relations, neorealists are of course most famous for treating states as unitary actors, but they are hardly alone. Some constructivists, even while stressing the importance of deconstructing the state, nevertheless recognize that states are often at least perceived as unitary actors and may assume relevant characteristics. Liberals as well, although tending to emphasize dynamics specific to the "second image" of domestic politics and regimes, utilize game-theoretic models to explain international cooperation for which it is often convenient to treat the state as a unitary actor. We do not argue that this is a fault; rather, that it is an important human tendency. Our argument here is to show how the content and variability of these representations affect behavior.
99. On the unitary actor assumption in international politics, see Kenneth N. Waltz, Theory of International Politics (Reading, Mass.: Addison-Wesley, 1979).
100. Wendt, "The State as Person in International Theory"
101. Helen Milner, "International Theories of Cooperation among Nations: Strengths and Weaknesses," World Politics, Vol. 44, No. 3 (April 1992), pp. 466-496.
102. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange."
103. Robert M. Axelrod, The Evolution of Cooperation, rev. ed. (New York: Basic Books, 2006).
104. We are well aware of the psychological literature suggesting that individuals may not display stable personality traits across situations; however, the personality psychology literature is clear that individuals remain stable in their characteristics within a given situation over time (i.e., temporal stability remains greater than cross-situational consistency).
105. See Walter Mischel and Philip K. Peake, "In Search of Consistency: Measure for Measure," in E. Tory Higgins, C. Peter Herman, and Mark P. Zanna, eds., Consistency in Social Behavior: The Ontario Symposium (Mahwah, N.J.: Lawrence Erlbaum Associates, 1982).
106. Frans B.M. de Waal, Chimpanzee Politics: Power and Sex among Apes (Baltimore, Md.: Johns Hopkins University Press, 1989).
107. Boehm, Hierarchy in the Forest.
108. Boehm, "Conflict and the Evolution of Social Control."
109. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange"
110. van Vugt and Kurzban, "Cogntive and Social Adaptations for Leadership and Followership."
111. Johan van der Dennen, The Origin of War: The Evolution of a Male-Coalitional Reproductive Strategy (Groningen, Netherlands: Origin, 1995)
112. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange"
113. van Vugt and Kurzban, "Cogntive and Social Adaptations for Leadership and Followership."
114. Boehm, Hierarchy in the Forest.
115. Van der Dennen, The Origin of War.
116. Wayne E. Lee, "Peace Chiefs and Blood Revenge: Patterns of Restraint in Native American Warfare, 1500-1800," Journal of Military History, Vol. 71, No. 3 (July 2007), pp. 701-741.
117. Quoted in Ellen Barry, "Putin Sounds Warning on Arms Talks," New York Times, December 29, 2009.
118. Stability is emphasized because the reputation that enables cooperation given a low discount rate is relatively difficult if that reputation is subject to change quickly and suddenly.
119. David Leblang and Shanker Satyanath, "Institutions, Expectations, and Currency Crises," International Organization, Vol. 60, No. 1 (Winter 2006), pp. 245-262.
120. Kenneth A. Oye, ed., Cooperation under Anarchy (Princeton, N.J.: Princeton University Press, 1986).
121. Milner, "International Theories of Cooperation among Nations."
122. Jonathan Mercer, Reputation and International Politics (Ithaca, N.Y.: Cornell University Press, 1996).
123. R. Brian Ferguson, "Violence and War in Prehistory," in Debra L. Martin and David W. Frayer, eds., Troubled Times: Violence andWarfare in the Past (Amsterdam: Gordon and Breach, 1997), p. 336
124. Napoleon A. Chagnon, "Life Histories, Blood Revenge, and Warfare in a Tribal Population," Science, February 26, 1988, pp. 985-992.
125. Christopher von Rueden, Michael Gurven, and Hillard Kaplan, "The Multiple Dimensions of Male Social Status in an Amazonian Society," Evolution and Human Behavior, Vol. 29, No. 6 (November 2008), pp. 402-415.
126. The strategic manipulation of the coalitional environment does not simply mean that humans expand their coalition whenever possible. Coalitions cannot expand indefinitely, given mounting problems of coordination as size increases. Therefore, strategic manipulation is not merely about maximizing size; it is also about the ability to influence coalitional composition and the distribution of resources.
127. See Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange"
128. Anthony C. Lopez, "Evolution, Coalitional Psychology, and War," in H-Diplo ISSF Roundtable on "Biology and Security," Vol. 1, No. 1 (2010), pp. 35-52, http://www.h-net.org/_diplo/ISSF/PDF/ISSF-Roundtable-1-1.pdf.
129. See Russell Spears, Bertjan Doosje, and Naomi Ellemers, "Self-Stereotyping in the Face of Threats to Group Status and Distinctiveness: The Role of Group Identification," Personality and Social Psychology Bulletin, Vol. 23, No. 5 (May 1997), pp. 538-553.
130. Tooby, Cosmides, and Price, "Cognitive Adaptations for n-Person Exchange."
131. Cheng, Tracy, and Henrich, "Pride, Personality, and the Evolutionary Foundations of Human Social Status."
132. We should acknowledge that there have indeed been efforts to "conditionalize" the debate, and thus we obviously agree that the impact of relative gains is "highly conditional" and that it does not necessarily and logically follow from anarchy alone.
133. See, for example, the nuanced discussion in David A. Baldwin, ed., Neorealism and Neoliberalism: The Contemporary Debate (New York: Columbia University Press, 1993).
134. Boyd and Silk, How Humans Evolved
135. Cosmides and Tooby, "Neurocognitive Adaptations Designed for Social Exchange."
136. Wrangham, "Evolution of Coalitionary Killing"
137. Phillip L. Walker, "A Bioarchaeological Perspective on the History of Violence," Annual Review of Anthropology, Vol. 30 (2001), pp. 573-596
138. Joseph M. Grieco, "Anarchy and the Limits of Cooperation: A Realist Critique of the Newest Liberal Institutionalism," International Organization, Vol. 42, No. 3 (Summer 1988), pp. 485-507.
139. Joseph M. Grieco, Robert Powell, and Duncan Snidal, "Controversies: The Relative-Gains Problem for International Cooperation," American Political Science Review, Vol. 87, No. 3 (September 1993), pp. 729-743.
140. Henry Tajfel and John C. Turner, "The Social Identity Theory of Intergroup Behavior," in Stephen Worchel and William G. Austin, eds., Psychology of Intergroup Relations (Chicago: Nelson Hall, 1986), pp. 7-24.
141. Jonathan Mercer, "Anarchy and Identity," International Organization, Vol. 49, No. 2 (Spring 1995), pp. 229-252.
142. Wagner, Flinn, and England, "Hormonal Response to Competition among Male Coalitions."
143. Martin Daly and Margo Wilson, Sex, Evolution, and Behavior, 2d ed. (Boston: Willard Grant, 1983).
144. Amotz Zahavi, "Mate Selection-Selection for a Handicap," Journal of Theoretical Biology, Vol. 53, No. 1 (September 1975), pp. 205-214.
145. Donald Symons, The Evolution of Human Sexuality (New York: Oxford University Press, 1979), p. 23.
146. Robert Trivers, "Parental Investment and Sexual Selection," in Bernard Campbell, ed., Sexual Selection and the Descent of Man, 1871-1971 (Chicago: Aldine de Gruyter, 1972), pp. 136-207.
147. There is the rare case of isogamy in some species in which male and female gamete size is equal.
148. Symons, The Evolution of Human Sexuality, p. 23.
149. William D. Lassek and Steven J.C. Gaulin, "Waist-Hip Ratio and Cognitive Ability: Is Gluteofemoral Fat a Privileged Store of Neurodevelopmental Resources?" Evolution and Human Behavior, Vol. 29, No. 1 (January 2008), pp. 26-34.
150. Joshua New, Max M. Krasnow, Danielle Truxaw, and Steven J.C. Gaulin, "Spatial Adaptations for Plant Foraging:Women Excel and Calories Count," Proceedings of the Royal Society B, November 7, 2007, pp. 2679-2684.
151. Wrangham, "Evolution of Coalitionary Killing."
152. Johnson et al., "Overconfidence in Wargames".
153. Wrangham, "Evolution of Coalitionary Killing."
154. Christian G. Mesquida and Neil I. Wiener, "Male Age Composition and Severity of Conflicts," Politics and the Life Sciences, Vol. 18, No. 2 (September 1999), pp. 181-189.
155. Stephen D. Biddle, Military Power: Explaining Victory and Defeat in Modern Battle (Princeton, N.J.: Princeton University Press, 2004).
156. For a dramatic example, see Tatiana Zerjal et al., "The Genetic Legacy of the Mongols," American Journal of Human Genetics, Vol. 72, No. 3 (March 2003), pp. 717-721.
157. John Tooby, Leda Cosmides, Aaron Sell, Debra Lieberman, and Daniel Sznycer, "Internal Regulatory Variables and the Design of Human Motivation: A Computational and Evolutionary Approach," in Andrew J. Elliot, ed., Handbook of Approach and Avoidance Motivation (Mahwah, N.J.: Lawrence Erlbaum, 2007), chap. 15.
158. One should be careful not to derive explanations of particulars from causal claims about averages. This hypothesis does not tell you that the more you benchpress, the more you will unequivocally be inclined to support aggressive foreign policies. The human aggression system is computationally complex, and many other features play a causal role in shaping the profile of human aggression. We argue only that strength represents one of the factors that enter into such a calculation.
159. See Azar Gat, "The Human Motivational Complex: Evolutionary Theory and the Causes of Hunter-Gatherer Fighting, Pt. 2: Proximate, Subordinate, and Derivative Causes," Anthropological Quarterly, Vol. 73, No. 2 (April 2000), pp. 74-88.
160. John Archer, "Testosterone and Human Aggression: An Evaluation of the Challenge Hypothesis," Neuroscience and Biobehavioral Reviews, Vol. 30, No. 3 (2006), pp. 319-345.
161. Rose McDermott, Dustin Tingley, Jonathan Cowden, Giovanni Frazetto, and Dominic D.P. Johnson, "Monoamine Oxidase A Gene (MAOA) Predicts Behavioral Aggression Following Provocation," Proceedings of the National Academy of Sciences, February 17, 2009, pp. 2118-2123.
162. Sell, Tooby, and Cosmides, "Formidability and the Logic of Human Anger."
163. Aaron Sell, "Regulating Welfare Tradeoff Ratios: Three Tests of an Evolutionary-Computational Model of Human Anger," Ph.D. dissertation, University of California, Santa Barbara, September 2005.
164. Sell, Tooby, and Cosmides, "Formidability and the Logic of Human Anger."
165. John E. Mueller, War, Presidents, and Public Opinion (New York: JohnWiley and Sons, 1973).
166. Lee, "Peace Chiefs and Blood Revenge."
167. For a counterexample, see Napoleon A. Chagnon, Yanomamö: The Fierce People, 3d ed. (New York: Holt, Rinehart, and Winston, 1983).
168. Gat, "The Human Motivational Complex: Evolutionary Theory and the Causes of Hunter-Gatherer Fighting, Pt. 1."
169. Mia Bloom, "Death Becomes Her: Women, Occupation, and Terrorist Mobilization," PS: Political Science and Politics, Vol. 43, No. 3 (July 2010), pp. 445-450.
170. Stephen Peter Rosen, War and Human Nature (Princeton, N.J.: Princeton University Press, 2007).