Steps toward convergence: Evolutionary psychology’ssaga continuesJerome H. Barkow1

Department of Sociology and Social Anthropology, Dalhousie University, Halifax, NS, Canada B3H4P9

Let us not ask whether the brainis ‘‘really’’ a biological computer.The more productive question iswhether it is useful to think of

the brain as a computer, one designedby evolution to solve problems of adap-tation via specialized ‘‘circuits’’ and ‘‘ar-chitecture.’’ Does this biocomputationalapproach, pioneered by Leda Cosmidesand John Tooby (1) and then developedand expanded by them and others [suchas David Buss (2, 3), Geoffrey Miller(4, 5), and Steven Pinker (6)] lead totheory and research that further ourunderstanding of human behavior? Crit-ics notwithstanding (e.g., ref. 7), the evi-dence of the article in this issue ofPNAS (8), indeed, of the myriad booksand research papers produced by theCosmides–Tooby school of thought, is‘‘yes.’’ But, of course, there are caveats.

Sell, Tooby, and Cosmides (8) positthe existence of welfare tradeoff ratios(WTRs), the ratio between the welfareof another and that of the actor. TheseWTRs are presented as ‘‘not just posthoc theoretical constructs but . . . realneurocognitive elements within thehuman motivational architecture.’’ IfSally’s WTR ‘‘circuitry’’ is giving a rela-tively high weight to Jane’s interestsrather than her own, the ratio will be inJane’s favor and she will do well in hernegotiations with Sally over resources.We humans have therefore been se-lected to seek to increase the WTR oth-ers are according us, and we can do thisbecause the WTR not only ‘‘integrates’’relatively fixed factors such as kinship,reciprocation, and aggression, but alsotakes many other factors into account,including our readiness to get angry. Ineffect, we may unconsciously use angerto bully another into recalculating aWTR in our favor, causing that personto give more weight to our intereststhan they otherwise would. But whouses anger in this tactical way? ‘‘Angeris more likely to be triggered when anactor is positioned to make the price ofresisting recalibration high’’ (8). Peoplewho are more ‘‘formidable’’ (physicallystronger) than others (generally males)are more able to ‘‘inflict costs on thetarget’’ and are therefore more likely touse anger. So are those who are moreable to confer benefits on others, e.g.,the attractive, especially attractivewomen. Sell, Tooby, and Cosmides pre-

dict that those who are formidable orattractive should have a ‘‘greater senseof entitlement,’’ be more prone to an-ger, and be more likely to see conflictsresolved in their favor than the less for-midable or attractive. Once a favorablesettlement has been reached, angershould wane. Their data are largely con-sistent with these expectations. Attrac-tive women and strong men are morelikely than others to use anger toincrease WTRs.

Does Hypothesis Intuitiveness Matter?Here is a small point: Some reviewersprivilege the counterintuitive hypothesis,dismissing the intuitive with ‘‘trivial, we

already knew that.’’ Are Sell, Tooby,and Cosmides (8) simply using complexlanguage to make commonsense predic-tions? They would argue, to the con-trary, that frequent anger is often la-beled a sign of weakness or even ofpathology rather than an attribute of thealready advantaged. In fact, however,folk wisdom tends to take the contraryview, seeing the strong and attractive asoften self-centered and selfish. This folkobservation, if accurate, would be con-sonant with the theory and findingssummarized in the previous paragraph.Let us ignore that possible fact. The de-gree to which a hypothesis is or is notconsistent with folk wisdom or intuitionis not ordinarily relevant to a scientificevolutionary psychology: if we acceptthat human intelligence is largely a so-cial intelligence and a product of socialcompetition then it would be surprisingindeed if folk wisdom was not some-times accurate.

Anger and CultureA more substantial issue is whetherthere are alternative evolutionary treat-ments competing with Sell, Tooby, and

Cosmides’ theory of the use of anger insocial interaction. It turns out that otherapproaches are more complementarythan competitive. For example, Fessler(9) argues that ‘‘the male flash of angeris ‘designed’ to diminish transgressionsin the service of acquiring and maintain-ing control over a variety of economicand social resources.’’ Rather than theo-rizing about the brain, however, Fesslerfocuses on explaining cultural variationin the use of anger. He predicts that theimportance of male anger will be highin societies in which ‘‘valuable resourcescan be [more easily] appropriated,’’‘‘overarching social institutions’’ offerless rather than more protection, andthe preservation of social relationshipsis relatively unimportant because indi-viduals do not depend heavily on thoserelationships. He finds strong supportfor this thesis in his analysis of Nisbettand Cohen’s (10) important work onhonor cultures in the American Southand Southwest. Fessler’s approach isparticularly useful for social scientistsworking in naturalistic settings, wherepeople have established social relation-ships and are mindful of how theircurrent behavior may affect their repu-tations. In such settings, even a biocom-putational approach would require amuch broader range of inputs and calcu-lations than anger and attractiveness.Sell, Tooby, and Cosmides, who are fullyaware that they have tested ‘‘just twoout of a larger potential set of negotia-tive factors,’’ would likely agree. Thereis no logical contradiction betweenFessler on the one hand and Sell,Tooby, and Cosmides on the other, andthere is no apparent impediment to thedevelopment of a broad theory of angerthat integrates the two sets of ideas.

Putting Ontological Status AsideHave Sell, Tooby, and Cosmides (8)conclusively established that as we inter-act with others our neurological systemsare automatically calculating WTRs?No, not unless one has a great deal offaith in construct validity: accurate pre-diction can make a construct useful but

Author contributions: J.H.B. wrote the paper.

The author declares no conflict of interest.

See companion article on page 15073.

1E-mail: barkow@dal.ca.

Traits that we may findunsavory are

nevertheless alsoproducts of our

evolutionary history.

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is not, in my opinion, sufficient for oneto be as certain of its ontological statusas are Sell, Tooby, and Cosmides. Whathas been demonstrated is that the WTRconstruct, like the biocomputation per-spective in which it is situated, is at thispoint in history a productive way inwhich to apply the evolutionary perspec-tive to human behavior. It is leading totheory, hypotheses, and data that arebroadly compatible with other evolu-tionary perspectives rather than devel-oping into an encapsulated and self-perpetuating citation circle. Eventuallythe Cosmides and Tooby biocomputa-tional approach may be replaced bymore complex theoretical formulations,but in the meantime, as the Bohr modelof the hydrogen atom did in its day forparticle physics, that approach is movingus forward and does not appear to haveany demonstrably superior competition.Why, then, has there been so much op-position to the approach, some of itrather emotional? The answer may haveto do with the unromantic portrait ofhuman psychology it is painting.

Perfectibilite PerdueThe most notable finding of the articleby Sell, Tooby, and Cosmides (8) is thatthe strong and attractive, the peoplewho are presumably winners in life, useanger to improve their bargaining posi-tion with those less strong andattractive. Assuming this finding is repli-cated cross-culturally and with conver-gent methodologies, what we have hereis one more rip in the romantic portraitof our species that many nonevolution-ists would prefer to continue to enjoy.From the unsentimental perspective ofevolution, however, not just anger butsexual jealousy, male sexual insistence,infidelity (on the part of both men and

women), sibling rivalry, preoccupationwith one’s relative standing, nepotism,and individual and collective aggressionare not pathologies or even errors to becorrected once and for all by moralityand religion or at least proper child so-cialization, they are strategies that haveoften, at least in the past, been biologi-cally adaptive. Like socially valued traitssuch as love, loyalty, cooperativeness,and forgiveness, traits that we may findunsavory are nevertheless also productsof our evolutionary history. Evolution-ary psychology is the enemy of thosewho, like some Marxists, espouse theperfectibility of our species and there-fore reject a field that asserts that theless attractive elements of our evolvedhuman nature are not errors to be elimi-nated on our way to perfection but bat-tles each generation must fight anew.Perhaps there are ways in which thetendency to use anger as a negotiatingtactic may be mitigated, just as goodparenting can mitigate sibling rivalry.From the perspective of Sell, Tooby,and Cosmides (8), however, tactical an-ger is part of our biology and cannot bedefinitively eliminated by, say, a changein the distribution of wealth.

It is perhaps romanticism, a nostalgiafor a perfectibilite perdue that, in part,has fueled the relentless attacks on theapplication of evolutionary biology tothe psychology of our species. Seger-stråle (11) has ably described the delib-erate campaign against E. O. Wilson’sfoundational Sociobiology: The New Syn-thesis (12), a campaign that now targetsevolutionary psychology (13). Antievolu-tionist attacks have waned, in recentyears, as Darwin’s insights have gradu-ally spread from field to field and now,in an often lamentably simplified form,are part of popular discourse. The par-

ticular approach represented by Sell,Tooby, and Cosmides (8), however, con-tinues to draw fire, perhaps becausetheir biocomputationalism unabashedlylocates our ‘‘failings’’ in the architectureof the human brain.

This is not to say that criticisms ofthis field are always entirely empty. Forexample, the plasticity of the developinghuman brain pointed out by Buller (7)and Gibson (14) suggest that biocompu-tational modules are likely to be vari-able and contingent, but it is difficult tosee this as a fatal conceptual weaknessbecause the framework easily encom-passes such variability. Even if the Cos-mides and Tooby school of thought isindeed guilty, at times, of simplification,that is only to be expected: theoreticalmodels necessarily simplify, and whenpredictions nevertheless receive empiri-cal support it is difficult to argue that asimplification is excessive.

It would be interesting to see Sell,Tooby, and Cosmides (8) move on tolink their work to the construct of self-esteem, an idea that received ratherearly evolutionary attention (15–17). Inthis view, self-esteem is an internal indi-cator of perceived relative standingwithin one’s membership groups. If theWTR is the construct calculating howmuch weight the actor should give tothe interests of the other, the other’sdemand/requirement for accommodationmay depend on that individual’s level ofself-esteem. Formidability and attrac-tiveness would be just two of the factorsaffecting level of self-esteem, whichwould also be in part situational. Thepoint here is that the article in this issueof PNAS (8) is just one part of a broadenterprise of research and theory that,while not yet ready for full integration,is at least on its way.

1. Cosmides L, Tooby J (1992) in The Adapted Mind:Evolutionary Psychology and the Generation of Cul-ture, eds Barkow JH, Cosmides L, Tooby J (Oxford UnivPress, New York), pp 163–228.

2. Buss D, ed (2005) The Handbook of Evolutionary Psy-chology (Wiley, Hoboken, NJ).

3. Buss D (2007) Evolutionary Psychology: The New Sci-ence of the Mind (Allyn & Bacon, Boston).

4. Miller G (2000) The Mating Mind: How Sexual ChoiceShaped Human Nature (Doubleday, New York), 3rd Ed.

5. Miller G (2009) Spent: Sex, Evolution, and ConsumerBehavior (Viking, New York).

6. Pinker S (2002) The Blank Slate: The Modern Denial ofHuman Nature (Viking, New York).

7. Buller DJ (2005) Adapting Minds: Evolutionary Psychol-ogy and the Persistent Quest for Human Nature (MITPress, Cambridge, MA).

8. Sell A, Tooby J, Cosmides L (2009) Formidability and thelogic of human anger. Proc Natl Acad Sci USA106:15073–15078.

9. Fessler DMT (2006) in Missing the Revolution: Darwin-ism for Social Scientists, ed Barkow JH (Oxford UnivPress, New York), pp 101–117.

10. Nisbett R, Cohen B (1996) Culture of Honor (Westview,Boulder, CO).

11. Segerstråle U (2000) Defenders of the Truth: The Battlefor Science in the Sociobiology Debate and Beyond(Oxford Univ Press, New York).

12. Wilson EO (1975) Sociobiology: The New Synthesis(Belknap, Cambridge, MA).

13. Rose H, Jencks C, Rose SP (2000) Alas, Poor Darwin: Argu-mentsAgainstEvolutionaryPsychology (Crown,NewYork).

14. Gibson KR (2005) in Complexities: Beyond Nature andNurture, eds McKinnon S, Silverman S (Univ ChicagoPress, Chicago), pp 23–42.

15. Barkow JH (1975) in Psychological Anthropology, edWilliams TR (Mouton, Paris), pp 373–388.

16. Barkow JH (1975) Prestige and culture: A biosocialapproach. Curr Anthropol 16:553–572.

17. Barkow JH (1989) Darwin, Sex, and Status: BiologicalApproaches to Mind and Culture (Univ Toronto Press,Toronto).

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