Precis of Vaulting Ambition: Sociobiology and the Quest for Human Nature

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Anthropology Faculty Publications Anthropology, Department of
August 1987
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HHuummaann NNaattuurree
Philip Kitcher
University of California, San Diego, La Jolla, California
Patrick Bateson (Comment by)
University of Cambridge, Cambridge, England
Jon Beckwith (Comment by)
Department of Microbiolgoy and Molecular Genetics, Harvard Medical School, Boston, Mass.
Irwin S. Bernstein (Comment by)
Department of Psychology, University of Georgia, Athens, GA
Patricia Smith Churchland (Comment by)
Philosophy Department and Cognitive Science Program, University of California, San Diego, La Jolla,
California
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Kitcher, Philip; Bateson, Patrick (Comment by); Beckwith, Jon (Comment by); Bernstein, Irwin S.
(Comment by); Smith Churchland, Patricia (Comment by); Draper, Patricia (Comment by); Dupre, John
(Comment by); Futterman, Andrew (Comment by); Ghiselin, Michael T. (Comment by); Harpending, Henry
(Comment by); Johnston, Timothy D. (Comment by); Allen, Garland E. (Comment by); Lamb, Michael E.
(Comment by); McGrew, W. C. (Comment by); Plotkin, H. C. (Comment by); Rosenberg, Alexander
(Comment by); Saunders, Peter T. (Comment by); Ho, Mae-Wan (Comment by); Singer, Peter (Comment
by); Smith, Eric Aiden (Comment by); Smith, Peter K. (Comment by); Sober, Elliot (Comment by); Stenseth,
Nils C. (Comment by); and Symons, Donald (Comment by), "Precis of Vaulting Ambition: Sociobiology and
the Quest for Human Nature" (1987). Anthropology Faculty Publications. 16.
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Philip Kitcher, Patrick Bateson (Comment by), Jon Beckwith (Comment by), Irwin S. Bernstein (Comment
by), Patricia Smith Churchland (Comment by), Patricia Draper (Comment by), John Dupre (Comment by),
Andrew Futterman (Comment by), Michael T. Ghiselin (Comment by), Henry Harpending (Comment by),
Timothy D. Johnston (Comment by), Garland E. Allen (Comment by), Michael E. Lamb (Comment by), W.
C. McGrew (Comment by), H. C. Plotkin (Comment by), Alexander Rosenberg (Comment by), Peter T.
Saunders (Comment by), Mae-Wan Ho (Comment by), Peter Singer (Comment by), Eric Aiden Smith
(Comment by), Peter K. Smith (Comment by), Elliot Sober (Comment by), Nils C. Stenseth (Comment by),
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of
Precis Vaulting Ambition:
Sociobiology and the Quest for
Human Nature
Philip Kitcher
DepartmentofPhilosophy, UniversityofCalifornia, SanDiego, LaJolla,
Calif. 92093
Abstract:Thedebate about thecredentials ofsociobiologyhaspersistedbecausescholarshavefailed todistinguish thevarietiesof
sociobiologyandbecausetoolittleattentionhasbeenpaidtothedetailsoftheargumentsthataresupposedtosupporttheprovocative
claimsabouthuman soeialbehavior. Iseekto remedybothdcfieieneies. Afteranalysisoftherelationshipsamongdifferentkinds of
sociobiologyandcontemporaryevolutionarytheory, Iattempttoshowhowsomeofthestudiesofthebehaviorofnonhumananimals
meet the methodological standards appropriate to evolutionary research. I contend that the efforts of E. O. Wilson, Richard
Alexander, Charles Lumsden, and others to generate conclusions about human nature are flawed, both because they apply
evolutionaryideas inan unrigorous fashion andbecause theyuse dubious assumptions toconnecttheirevolutionaryanalyses with
their conclusions. This contention rests on analyses ofmany ofthe major sociobiological proposals about human social behavior,
including: differences in sex roles, racial hostility, homosexuality, conflict between parents and adolescent offspring, incest
avoidance, the avunculate, alliancesincombat, female infanticide, andgene-culturecoevolution. VaultingAmbitionthusseeksto
identifywhatisgoodinsociobiology, toexposetheerrorsofprematurespeculationsabouthumannature,andtopreparethewayfor
serious study ofthe evolution ofhuman social behavior.
Keywords: behavior; culture; environment; evolution; genes; genetics; heredity; human nature; sociobiology
The sociobiology debate cial distinctions and because they have not scrutinized
thearguments thatare supposedto supportthe provoca
ThechiefaimofVaultingAmbition(henceforthAmbition) tive theses. Ambition uses the philosopher's favorite
C
is to end a debate that has occupied biologists, social tactics. I draw distinctions and I analyze arguments.
scientists, and humanistsfor the lastdecade. I claim that
the credentials of sociobiology cannot be properly as
sesseduntil we make some importantdistinctions. First, Varieties of sociobiology
there are some exciting developments in recent evolu
tionary thcory that have been used to illuminate some There is a very broad discipline that is "the systematic
aspects of the behavior of nonhuman animals. Second, studyofthebiologicalbasisofallsocialbehavior"(Wilson
there is a potential science that studies the evolution of 1975, p. 2)andthataddressesquestionsaboutthemecha
human social behavior. Third, there are some particular nisms, development, function, and evolution of social
provocative theses about human nature and the inev behavior. Ineffect, this discipline, broadsociobiology, is
itabilityofhumansocialinstitutions. Ihopetoexplainthe approximately the field defined by Tinbergen in his
success of the first kind of sociobiology, to expose the account of the four "whys" of behavioral biology (Tin
pretensions ofthe last, and to prepare the way for the bergen 1968, p. 79). Most of the discussion about so
serious pursuit ofthe second. ciobiology focuses on a narrower domain. Narrow so
Humansociobiologyhasbeenportrayedbyitscriticsas ciobiology tackles questions ofevolution and offunction
adoctrine thatperpetuatesinequitiesonthebasisofsex, (the two are linked because, in the pertinent sense, the
class, and race. Although the political import of the attributionoffunction consists in the identificationofthe
conclusions advanced by some sociobiologists has to be selection pressure that maintains the behavior).
acknowledged, the debate is not ultimately a political So far, I have characterized sociobiology as a field (or
one. We need to know whether the provocative conclu fields)ofstudy. Butwecanalsoconsidersociobiologyasa
sions are well supported by the available evidence. Pol theory that supplies answers to the questions that con
itics intrudesonthesceneonlvbecausethecostsoferror stitute the field. I argue that, insofaras there is a theory
may be grave, so that we a;e ill-advised to lower our within narrow sociobiology, it is general evolutionary
epistemological standards. theory (Ambition, Chapter4). Theoreticalsociobiologyis
Ibelievethatthesociobiologydebatehas generated so thusirresistible- atleastforanyonewhoacceptscontem
much heat because the participants have neglected cru- porary evolutionary theory.
© 1987CambndgeUniversity Press 0140-525x/87$5.00+.00 61
Kitcher: Problems ofhuman sOciobiology
To appreciate the significance ofthis point we need a inquire about the actual forces that have been at work.
clearviewofthe characterofevolutionarytheory. Chap Since we may have a good answer to the question about
ter2 ofAmbitionattempts to provide this. I suggestthat possibilitywithouthavingstrongevidenceinfavorofany
evolutionarytheory, inallitsversionsfrom Darwintothe actual scenario, we should make distinctions among so
present, is best thought of as having three parts. Any ciobiologicalproposalsthattackle thesedifferentkindsof
version ofthe theory focuses on a set ofquestions (the problems.
questions it takes to fall within its domain), offers asetof Moreover, sociobiological research will also vary ac
strategiesorschemataforansweringthesequestions, and cordingtothetraitswhosepresenceitseekstoaccountfor
sets forth some general claims about the evolutionary and the sizes ofthe groups within which those traits are
process. Evolutionary questions are answered by devel manifested. The latter type of variation is particularly
oping structured narratives that exemplify the schemata important. Manynarrowsociobiologistsfocusonapartic
furnished by the theory. Thus, to take one simple exam ular species (speckled wood butterflies, olive'baboons);
pIe, Darwin'soriginalversionofthe theoryproposesthat others try to account for behavior across a very broad
questions of biogeographical distribution are to be an group (all birds, all vertebrates with internal fertiliza
swered byrelatinghistoriesofdescentwith modification, tion). Obviously, itis harderto defend broadgeneraliza
so that we would explain the current distribution ofthe tions than to support local conclusions about a single
marsupials, for instance, by tracing the history oftheir species. Furthermore, when the generalization covers
radiation and speciation. our own species (or any other species in which cultural
Within the last thirty years there have been some transmission mightplayamajorrole), there maybegood
importantdevelopmentsinevolutionarytheorythathave reason to think that there is no single evolutionary sche
enabledus totakeafar moresophisticatedviewofanimal ma that applies to all members ofthe group.
socialbehavior. ThecontributionsofHamilton, Maynard The mainpointofChapters2-4ofAmbitionis toshow
Smith, Williams, Trivers (Ambition, Chapter 3), and how there are all kinds ofenterprises thatfall under the
others can be seen as providing us with more refined rubric ofnarrow sociobiology. I also try to assemble the
views about the evolutionary process and enriching the methodologicalcanons thatare appropriate for assessing
set of strategies available for answering evolutionary work in evolutionary theory. Hence these chapters pre
questions. Theoreticalsociobiologyisirresistiblebecause pare for the work I regard as crucialfor the resolution of
ofthe cogency ofHamilton's claims about the dynamics thesociobiologycontroversy: thepiecemealevaluationof
ofinclusivefitness and Mavnard Smith's theoremsabout particular sociobiological explanations.
the existence ofevolutiona'rily stable strategies in partic
ular game-theoretic situations [see Maynard Smith:
"Game Theory and the Evolution of Behaviour" BBS Pop sociobiology
7(1) 1984]. Like the principles of population genetics,
resultsofthis kindareacceptedbecausetheyfollowfrom Butmoreisatstakethansimplythe legitimacyofspecific
some definitions and some very well confirmed results suggestions about the evolution and function of bits of
about gene transmission (grounded quite independently behaviorin humans and otheranimals. Sociobiology has
ofany evolutionary considerations). attracted broad interdisciplinaryattention because some
This does not mean that the particular answers that ofits adherents promise a new theory ofhuman nature.
sociobiologists give to questions about the evolution or This is mostevident in someofthe workofE. O. Wilson
thefunction ofapieceofsocialbehaviorareeithercorrect (see particularly Wilson 1978) and in that of his most
or warranted by the available evidence. We should dis militant supporters (Barash 1979;van den Berghe 1979).
tinguish the brilliant insights of Hamilton, Maynard [See also the multiple book review of Lumsden &
Smith, and others in alerting us to evolutionary pos Wilson's: Genes, mind and culture, BBS 5(1) 1982.]
sibilities- or, in mypreferredterms, insupplyinguswith However, the same generic idea - namely, that ofad
newstrategiesforexplainingparticularevolutionaryphe vancing from evolutionary explanations to claims about
nomena - from the application oftheir ideas in specific human nature - is present in the writings ofAlexander
instances. Oncewehavemadethisdistinction, wereacha (1979) and in the joint work of Lumsden and Wilson
point that is, in my judgment, absolutely indispensable (1981; 1983). Despite specific differences among the
for any serious evaluation ofsociobiology. The particular various authors, I conceive all of them as practicing a
accounts that sociobiology supplies have to be evaluated distinctive kind of sociobiology, which I call "pop so
on their individual merits and it is quite possible that ciobiology."(Thenamewaschosento reflectthefact that
some uses ofevolutionary schematato answer questions this work is not only what is commonly thought of as
abouttheevolutionofsocialbehaviorareasimpressiveas sociobiology but is also designed to command popular
anything in evolutionary theory, whereas others fall far attention. However, the name is less important than the
short of the standards that evolutionary theorists rou category. We need some label to mark this body of
tinely and properly demand. research, and readers who prefer to may treat "pop
Furtherdistinctionsarealsoimportant. Sometimesour sociobiology" as a meaningless tag without loss to the
evolutionary questions are concerned with the actual argument.)
selectionpressuresthathaveshapedormaintainedatrait Anyversionofpopsociobiologyconsistsofacollection
inapopulation. Onotheroccasionswewanttoknowhow of proposals within narrow sociobiology - specifically,
it is possible that a characteristic that appears to reduce proposalsabouttheevolutionofitemsofhumanbehavior
the fitness ofits bearers is maintained in the population. - together with some extra machinery. The purpose of
Sowe mayask how it is possible thatworkersterilityhas the extra machinery is to connect the evolutionary con
been maintained in the social Hymenoptera or we may clusions with doctrines about human nature. The most
62 BEHAVIORALAND BRAIN SCIENCES (1987) 101
Kitcher: Problems ofhuman sociobiology
readily comprehensible version ofpop sociobiology can 2. When we find B in (virtually) all members of
be found in Wilson's early writings (1975;1978). G, we can conclude that B became prevalent and
In his lastchapter, Wilson (1975)announcesanumber remains prevalent through natural selection, specifi
ofconclusions about human beings: We are xenophobic, cally through the contribution to fitness identified at
deceitful, aggressive, and "absurdly easy to indoctri step 1.
nate." Any evaluation of Wilson's claims about human 3. Because selection can only act where there are
nature must address two main questions: What does the genetic differences, we can conclude that there are
thesis that humans have certain properties "by nature" geneticdiflerencesbetweenthecurrentmembersofG
mean? Howare Wilson's conclusions supposed to follow andtheirancestors(andanyoccasionalrecentdeviants)
from his evolutionary analyses? The initial criticism of who failed to exhibit B.
Wilson typically answered the first question by attribut 4. Because there are these genetic differences and
ing to him a thesis of genetic determinism. Wilson's because the behavior is adaptive, we can show that it
assertionsthathumanbeingsare "bynature"xenophobic will be difficult to modifY the behaviorby altering the
or that men are "naturally" hasty and fickle, whereas social environment, in the sense that there will either
women are "naturally" faithful and coy, have been in be no combinations of environmental variables that
terpretedas the claim that these traits are caused by the yieldastateinwhichBisabsent, orelsesuchenviron
relevant genotypes. Wilson has responded to the crit mental variables can only be realized by abandoning
icism bydisavowing anysimplisticgeneticdeterminism. widely shared desiderata. (pp. 126-27)
He endorses the commonplace that human phenotypes Oncewe have formulated the sociobiological program
(including human behavioral phenotypes) are the joint in this way, we can see that further claims must be
result of genotypes and environments. So what do the scrutinized, beyondtheproposalstoapplyschematafrom
assertions about "human nature" mean? evolutionarytheory. Therearevariousways inwhich the
Chapter 1 ofAmbition develops an interpretation on program might go wrong. At the first step ofthe ladder,
which Wilson's theses about human nature are seen as the application ofideas from evolutionarytheory may be
claims about the norms of reaction for items of human carried out unrigorously (see previous section). More
behavior. Theproposalthat"thereisacost, whichnoone over, the language used to describe behavior across a
yet can measure, awaiting the society that moves either large and diverse group oforganisms may itselfsmuggle
from juridical equalityofopportunity between the sexes in evolutionary assumptions. When the analysis of fit
toastatisticalequalityoftheirperformanceintheprofes ness-maximizing behavior is compared with what the
sions" (Wilson 1978, p. 147) should be understood as animalsactuallydo, theremaybetoolittledatatosupport
contendingthatthe norms ofreactionforcertainkinds of the conclusion ofform 2. Or there may be discrepancies
human attributes (including both male and female pro betweenthedeliverancesoftheanalysisoffitnessandthe
pensities to compete for various kinds of positions in actualbehavior, discrepancies thatcanonlybeexplained
society)are shapedin suchawaythatanycombinationof by introducing extra variables that would subvert the
environmental variables that would produce statistical original analysis. The step from analysis offitness to a
equality of performance would be realized only in a history ofselection also deserves scrutiny, for the thesis
society that sacrificed some other things that we find that evolution - even evolution under selection - fixes
valuable. A simplerillustration is provided by the thesis thefittest phenotype is notas uncontroversialas it might
that the "ideals of some feminists" - increased male appeartobe. Finally, evenifwecanreachstep3, itisnot
parentalcare, increasedfemale sexualfreedom - maybe obvioushowtoattainstep4.Thefactthattherehasbeena
"biologically inconsistent" (Kleiman 1977, p. 62). Here, history of selection and that there have been genetic
what is being suggested is that the norm ofreaction for changes in a lineage so that people behave in particular
maleparentalcare(moreexactly, forthemalepropensity ways in our typical environments does not obviously
for caringfor young) and the norm ofreaction for female entailanythingabout the possibility offinding variations
sexual freedom have the property that as you adjust the on the behavior in different social environments.
environmentalvariablestoincreasetheoneyouautomat Chapters 5-8 of Ambition attempt to articulate all
ically decrease the other. these points, and to show that the main claims of pop
I argue thatthis interpretation makes the claims about sociobiology, as developed inWilson'searlywritings, fall
human nature advanced by Wilson and his followers prey to some ofthe errorsjust mentioned. My aim is to
intelligible, and itdoes not commit them to denying the identifyasurfeitofsuspects. Each suspect is guiltysome
commonplace wisdom about the role ofboth genes and ofthe time, no suspect is guilty all ofthe time, and each
environment in the determination ofbehavior. But how grand conclusion about human nature involves at least
aretheseclaimstobedefendedbyadvancingconclusions one guilty suspect.
about the evolution ofhuman socialbehavior?Chapter 1
ofAmbitionsuggestsacrudelineofargument that might
enableWilson to climbfrom nature up to human nature. Evolutionary modeling: The good, the bad, and
This line ofargument is refined in Chapter4 as Wilson's the ugly
ladder (the revised, standard version):
1. By using the standard methods for confirming Chapter5isconcernedwiththeuseoftheschematafrom
evolutionary histories, we can confirm hypotheses to contemporary evolutionary theory - in particular sche
the effect that all members ofa group G would max mata that use the insights of Hamilton and Maynard
imizetheirfitnessbyexhibitingaform ofbehaviorBin Smith - to understand various kinds of animal social
the typical environments encountered by members of behavior. I begin with two examples that seem to ex
G. emplifYthe rigorfound in thebestevolutionaryanalyses:
BEHAVIORALAND BRAIN SCIENCES (1987) 101 63
Kitcher: Problems ofhuman sociobiology
Parker's study ofcopulation time in the dung fly (Parker have at best a promissory note for some possible future
1978) and the research of Woolfenden (and others) on analysisofsomeoftheforms ofbehaviorlumpedtogether
helpingat the nest in the Floridascrubjay(Woolfenden in Wilson's large generalization.
1975; Woolfenden & Fitzpatrick 1978; Emlen 1978; I continue by looking at one of the most notorious
1984). In both cases, the strength of the conclusions proposals of pop sociobiology, the claim that the dif
depends on the possibilityofformulating precise mathe ferenceingametesizebetweenmalesandfemalesunder
matical models, of using experiment or observation to writes an analysis of sexual behavior on which "It pays
determinethevalueofcrucialparameters, andofmaking males to be aggressive, hasty, fickle, and undiscriminat
detailed observations of the behavior. Nonetheless, al ing" and "it is more profitable for females to be coy, to
though both studies are extremely suggestive, I argue hold back until they can identify males with the best
that certain important questions remain unresolved: In genes"(Wilson 1978, p. 125). [Seealsothe multiplebook
deed, ItakeittobeameritoftheresearchIdescribethat review of Symons: The Evolution ofHuman Sexuality,
it structures our ignorance by identifying precise ques BBS 3(2) 1980.] I trace the argument to its roots in
tionsthatweneedtoansweriftheanalysesaretobetaken Trivers's model of asymmetrical parental investment
one step further. Thus I endorse Emlen's verdicton the (Trivers 1972), and I show that a more careful game
presentstateofresearchintothephenomenonofhelping theoretic analysis is compatible with a number ofcom
at the nest (or den): "Considerable advances have been binations ofmale and female strategies. In particular, a
made both in the development oftheory pertaining to simple game-theoretic model reveals the possibility ofa
cooperative behavior and in the collection ofempirical stable polymorphism. In light ofthis analysis (which, I
field data. We now have before us a preliminary set of admit, is only the beginning ofa model for any compli
models and testable hypotheses. The decade ahead cated vertebrate), I consider the relation between
should be an exciting one as we begin to see vigorous Wilson's claims and the behavioral data. I show that the
testingofthesevarioushypotheses"(1984, pp. 338-39). I "exceptional cases" are typically treated by using Wil
applaud not only the imagination and care with which son'sassumptions about "the optimal male strategy"and
Parker, Woolfenden, Emlen, and others in the "behav "theoptimalfemalestrategy"as abasis, andbyintroduc
ioral ecology" tradition approach their research, butalso ingspecialhypothesesadhoctoexplainawaydeviations,
the caution with which they announce theirconclusions. and Iarguethatweshouldhavenofaith inthegerryman
Notallstudiesofthebehaviorofnonhumananimalsare dered generalization that results. Thus, I conclude,
as rigorous as these. I continue by examining some Wilson's analysis ofsexual strategies is inadequate.
research that is suggestive but that falls short of the Chapter5 concludeswith abrieflook at some casesin
standards that evolutionary analyses oughtto meet. Per which the evolutionary analysis seems even more hasty:
haps the mostimportantkindoflapseis thatillustratedin the adaptive value of"ecstasyatfootball games" (Wilson
Orians's pioneering studyofmatingsystems in birds and 1975, p. 167), of being "homesick in foreign places"
mammals (Orians 1969). Here, Orians offers a simple (Wilson 1975, p. 274), offorebearance incombat(Barash
model designed to specify when it will be advantageous 1979, p. 183), andofdominancedisplaysinmen(vanden
for a female to mate with a male who has already mated. Berghe 1979, p. 197). My intention is to juxtapose and
His model Yields qualitative predictions, which, as he comparesuchpopsociobiologicalproposalswiththework
acknowledges, are not always satisfied. Specifically, the of Parker, Woolfenden, Emlen, and Orians, and even
model predicts thatswans, geese, and ducks oughtto be with Wilson's own, more serious, efforts. The central
polygynous. Orians proposes to square the prediction theme ofChapter 5 is that narrow sociobiology covers a
with the observed finding by noting that, among these continuumofcasesandthat, asweunderstandthe merits
birds, monogamy occurs only in high-latitude species, ofthebestexamples, weshallseeclearlythedeficiencies
and he suggests that there is apremium on quickbreed of the analyses that occur in provocative pop socio
inginhigh-latitudespecies. Ineffect, thisistointroducea biological discussions.
new variable, not previously recognized in the model,
and Orians fails to consider whether this introduction
might subvert the conclusions obtained earlier. Anthropomorphism and reductionism
The next stage brings us to the kind of example on
which pop sociobiologists like to build. I consider Wil Two ofthe most common criticisms leveled against pop
son's analysis ofdefensive behaviorin vertebrates (1975, sociobiology are that it engages in unwarranted an
pp. 121-22). This, I argue, is flawed in numerous re thropomorphism and that it generates its conclusions by
spects. First, itisfarfrom clearthat there is any uniform making false, reductionist assumptions. Chapter 6 en
model that will apply to all the situations that Wilson deavors to make these charges precise.
intendsto cover- situationsinwhicha "dominant"male Use ofthe same terminology to cover the behavior of
exposes himselfto dangerindefense ofatroop. Isuggest humans and of nonhuman animals can easily disguise
thatthereareanumberofdifferentquestionsaboutthese undefended assumptions about similarity ofstructure or
situations and that Wilson fails to distinguish among offunction. To takeanotoriousexample, ifitis proposed
them. The claims about inclusivefitness are treatedvery thatrapeiscommittedbybothmallardsandmen, andthe
selectively: Wilson considers inclusive fitness maximiza proposal serves as the basis for attributing a genetic
tionfor some ofthe participantsbutnotfor others. Some predispositiontocommitrape(or, inthetermsofBarash,
ofthe claims about defensive behavior in ungulates are 1979, finding the idea of rape "stimulating"), then we
beliedbythe detailedfield studies (Kruuk1972). Discre must ask ifthere is any common mechanism underlying
panciesbetweentheanalysisandcasesthatWilsonrecog the behavior ofmen and ofmallard males or ifthere is
nizes as anomalous are unresolved. Here, I suggest, we some common function that the behavior fulfills in the
64 BEHAVIORALAND BRAIN SCIENCES(1987) 101
Kitchel': Problems ofhuman sociobiology
two cases. I argue that neither assumption can be sus groupdirectlyreflectsthepropensitiesoftheparticipants
tained,andthattheentire"scientificcase"isbornebythe is a particularly crude type ofreductionism.
question-begging terminology. Amoresophisticatedreductioniststrategyis todismiss
This sort of anthropomorphism is only the most appealstotheefficacyofsocialinstitutionsandthehistory
egregious instance ofconceptual malfunctioning in pop of a society as invoking illegitimate entities. I contend
sociobiology. I also consider two more subtle examples: thatthis strategyisalsofaulty, andthatwecanappreciate
ourvocabulariesfordiscussingmatingsystemsandpower theimportanceofhistoricaleventsandculturaltransmis
relations. Consider the family of terms "monogamy," sion without supposing that Clio herself needs to be
"polygyny," "polyandry," and "promiscuity," the stock added to the inventory of evolutionary forces. Thus I
in-trade not onlyofpopsociobiologybutofmanyserious showthatfitness-maximizingbehaviormaybecomeprev
studies ofanimal behavior. These expressions need tobe alent in a group through cultural transmission, without
handled with enormous care. Even in the relatively any changes in the gene pool. In this way, the passage
rigoroususageofthebehavioralecologists(see, forexam from step 1 to step 2 ofWilson's ladder is more prob
ple, Krebs & Davies 1981), there are three potential lematic than it appears.
sourcesoftrouble. First, therearedifferentwaystoapply Chapter 6 concludeswith an investigation ofthe ways
the concepts to at least some animal groups by choosing in which unwarranted reductionist assumptions can be
alternative time scales. I illustrate the point by showing used to help negotiate thefinal stepofWilson'sladder. I
how we could interpret the behavior ofchimpanzees as beginfrom thestraightforwardpointthatevenifwewere
either promiscuous or polyandrous (more exactly, as to discover that human genes combine with one range of
exemplifying an arrangement in which males are suc environments to issue in a behavioral phenotype, we
cessively polygynous, females simultaneously poly wouldnotbeentitledtoanyconclusionsaboutthefixityof
androus). Second, we can vary the construal ofthe con behavioracross all environments, unless we have reason
cepts by supposingthat matinginvolves onlycopulation; tothinkthattherangeofpossiblehumanenvironmentsis
that it involves copulation and reproduction; that it in fully represented inour sample. Pop soci,obiologists may
volves copulation, reproduction, and cooperation (of try to fill the gap in one ofthree distinctways: They may
somespecifiedkind). Third, weneedtoconsiderwhether proposethatthesimplestwayforselectiontooperateisto
our attribution ofa mating system to an animal group is favoradispositiontoexhibitbehaviorthatisinsensitiveto
supposed to represent the actual mating behavior of environment; they may suggest that since some human
members of the group or the underlying dispositions, behavioral propensities are old adaptations, fixed in ani
which may be compromised in practice by ecological mals with rudimentary cognitive abilities, we have no
constraints. Apparently, iftheinterestisinfathomingthe reason to think that they can be modified in ways that
dispositions of individual animals, then we should be employ our burgeoning mentality; or they may empha
concernedwith the matingpatterns thatwouldbeexhib size the constancy of the human phenotype under a
ited under ideal conditions, in which the ecological con variety ofcultural conditions.
straintsare removed. Thedifferencecanbeillustratedby Myresponsetothefirsttwosuggestionsisthatwehave
considering gibbons, normally classified as "monog no reason to think that selection will favor fixed tenden
amous." Since the most plausible account ofthe gibbon cies to behavior or to dismiss the pOSSibility that an
mating system is that it results from the distribution of increase in cognitive powers might radically alter old
food, whichforces females to disperse and thus prevents behavioral mechanisms. (In fact, we can give a casual
males from trying to monopolize a cluster of females, sociobiological argument for thinking that evolution
thereis no reasonforthinkingthattheindividualdisposi oughttooperateinthisway, replacingcrudemechanisms
tions ofindividualgibbons are differentfrom thedisposi withtricksthatcanyieldsubtleresponsestoenvironmen
tionsofsomeoftheircloserelatives(orangutans, gorillas, tal conditions, and thus bring an increment in fitness.
andchimpanzees, noneofwhichareconsidered "monog Thisargumentisnobetter- andnoworse- thanmanyof
amous"). thespeculationsofpopsociobiology!)The issueofreduc
Analogous points can be made about the concept of tionism returns with the last strategy, the appeal to the
dominance, which, I suggest, can best be understood by universality ofcertain forms ofhuman behavior.
thinkingfrom theperspectiveofevolutionarygame theo Consider Wilson's (1978) claim that differences in the
ry. Once these points are appreciated we should lookon frequency ofreflexive smiling between infant boys and
pop sociobiological theses about "male dominance dis girls signal innate behavioral differences. That claim can
playsinhumans"andthe "naturalmatingsystemofHomo becounteredbyproposingthatparentscareforboysand
sapiens" (Barash 1979; van den Berghe 1979; Wilson girls in different ways (Money & Ehrhardt 1972). If
1975) with a more skeptical eye. Wilsonistorebutthisobjection, thenhe mayofferanyof
One variety of reductionism that occurs in pop so thefollowing reductionisttheses: (a)Thecaringbehavior
ciobiology is related to one of the errors already can of parents makes no difference; (b) even if the caring
vassed. Pop sociobiologists often conflate the pattern of behaviorofparents makes a difference, parental tenden
behaviorrevealed ina groupofanimals with the disposi cies to respond differently to boys and girls is itselfan
tions to behavior ofthe individual participants. Wilson indicatorofsexdifferences;(c)evenifthecaringbehavior
(1978) uses an analysis of the behavior of tribes and of parents makes a difference, and even if it is the
nations to conclude that "humans are strongly pre expressionofthesocializationoftheparents, thefactthat
disposed to respond with unreasoning hatred to external the parents have been socialized in these ways reflects
threats and to escalate their hostilitysufficientlyto over biological differences. I argue that there is no reason to
whelmthesourceofthethreatbyawidemarginofsafety" think thatany ofthese three theses is correct, and, more
(p. 119). I argue that supposing that the behavior ofthe generally, that we are not entitled to pursue the reduc-
BEHAVIORALAND BRAIN SCIENCES(1987) 101 65
Kitcher: Problems ofhuman sociobiology
tionist tactic ofignoring social and historical forces. As a optimality analyses onlywhen we have some knowledge
numberofWilson'scritics (Bock1980;Sahlins 1976)have ofthe developmentalconnections between thataspect~f
argued, and as Wilson has now conceded (Lumsden & the phenotype in which we are primarily interested and
Wilson1981; 1983),wemustrecognize the roleofsociety othertraits ofthe organism. The route to the reconstruc
in human development. tion ofphylogeny may lie - atleast in part- through the
study ofontogeny.
Chapter 7 concludes by showing how pop socio
Evolution and optimality biological arguments frequently cast aside the caution
with which optimality analyses are treated in other nar
Another common indictment of sociobiology (which is row sociobiological studies. I consider Barash's (1979)
sometimes directed against research in narrow so blanket assumption about the link between optimality
ciobiology outside pop sociobiology) is that it pursues an andevolution, Wilson'sclaimsabouttheeffectsonfItness
illegitimate adaptationist program, in which the evolu ofreligiouspractice(1978)andofadaptingtosubordinate
tionary process is regarded as generating optimal phe status(1975), Alexander'sbroadclaimsfortheoptimiZing
notypes(Gould& Lewontin1979). Chapter7ofAmbition power ofevolution (1979), and, finally, an "explanation"
takes up this objection. I argue that when one takes ofthe adaptive significanceofthefemale orgasm (Bernds
seriously the genetics of the evolutionary process it is & Barash 1979).
hard tofindaversionoftheclaimthatevolutionproduces
the best available phenotype that is both nontrivial and
true. I consider the ways that optimality arguments are Four major examples
used in narrow sociobiology generally, and how serious
research on nonhuman animals is frequently attuned to At this stage, the catalogofthefoibles exemplifIedin the
the possibilities thatsucharguments mayprove mislead mostprominentpopsociobiologicalprogramiscomplete.
ing. Finally, I review some ofthe incautious appeals to However, eachofthe examples sofar discussedhas been
optimality that abound in pop sociobiology. viewed as illustratingone specialkind ofmistake. Chap
Darwin's central insight is often presentedby borrow ter 8 of Ambition seeks to supplement this piecemeal
ingasloganfrom Spencer. Evolutionunderselection, itis approachbylookingextensivelyatfourmajorexamplesof
said, is the survival ofthe fittest. The most elementary pop sociobiology in the tradition ofWilson's early writ
ways offormulating this idea precisely lead immediately ings. The cases considered are Wilson's treatment of
to trouble. For example, it is not true that natural selec homosexuality (1978), Barash's attempt to explain racial
tion will lead to the fixation of the optimal available hostility (1979), Trivers's claims about conflict between
phenotype. There may be no optimal available phe parents and offspringin adolescence (1974), and van den
notype, or the optimal phenotype may be coded by a Berghe's hypotheses about incest avoidance (1983).
heterozygote, or, ifthere are more than two alleles at a Wilson's argument for thinking that homosexuals
locus, the fitness relations among the genotypes may mightconstituteavertebrate "caste"(1975)startswithan
preventthefixationofthefittest. Iillustratetheproblems unscrutinized assumption to the effect that there is a
I
withexamplesfromTempleton(1982)andfrom Lewontin single category of homosexual behavior, and that in
and White (1960). The problems can be overcome by stancesofthiscanbefoundinawidevarietyofhumanand
tinkering with the notion ofavailability, but the cost of nonhuman contexts. He continues by inflating the cre
such tinkering is that the original slogan becomes a dentialsofstudies in behaviorgeneticsandofferingsome
truism. speculations about ways in which a propensity to have
Moreover, it is wrong to think ofselection as the only some homosexual offspring might boost one's inclusive
evolutionary force. I show that chance effects can playa fitness. I argue thatthere is noreason to believe in these
large rolein theevolutionofsmallpopulations, andargue alleged advantages.
that the effects of stochastic factors can sometimes be Barash'streatmentofinterracialhatredisalsoflawedin
permanent. Arguments to the efI'ect that chance and several ways. First, some precise but limited results
selectionworkharmoniously to guideapopulationto the aboutkin recognition ingroundsquirrelsareinterpreted
global optimum (see Templeton's 1982 refurbishing of as showing that selection favors a general tendency for
insightsduetoSewallWright)dependcriticallyonprem animals to be "nice" to their kin. Second, Barash (1979)
ises to the effect that the adaptive topography remains appealstothefact thatschoolchildrencanbedividedinto
relatively constant over time and that selection is not groups that are mutually antagonistic to buttress the
frequency-dependent. I conclude that a complete adap conclusion that there may be "an evolutionary tendency
tive story for everything would be mistaken. to racism" (p. 153). Finally, he points out that people of
The difficulties ofSpencer's slogan are onlyhalfofthe difI'erentracessharefewer genes than peopleofthesame
challenge to the use ofoptimality arguments. There are race, and claims that we can expect "kin-selected al
also methodological troubles, which arise from the pos truism" to produce antagonism toward those ofdifferent
sibilityofourmisidentifYing the optima, even in cases in races. Icounterby(a)showingthataproperapplicationof
which we may assume that evolution hasfixed thefittest Hamilton's (1964) ideas about inclusive fitness would, at
available phenotype. The most sensitive proponents of best, only supportarelatively rare tendency to discrimi
optimality analyses (for example, Oster & Wilson 1978) nate people ofthe same race from those who are racially
recognizethesourceofthesetroublesandadmitthatsuch different, andby(b)distinguishingthethesisthatwehave
analyses involve guesswork. I compare their self-crit a propensity to aid those who share our genes from the
icisms with the points made by Gould and Lewontin thesisthatwehaveapropensitytobehostiletothosewho
(1979), and argue that we have good reason to rely on do not.
66 BEHAVIORALAND BRAIN SCIENCES (1987) 101
Kitcher: Problems ofhuman sociobiology
Bothofthese examples occurin popularpresentations so forth). Second, whatever explanation ofsibling incest
ofpop sociobiology, andsoinvitethe response thatthere avoidance is favored, that account should be integrated
are more rigorous arguments in more scholarly discus withanalysesofotherforms ofsexualrelationsandavoid
sions. My third and fourth examples are designed to ance ofsuch relations among close relatives. Third, the
counter this suggestion. At the end ofhis seminal paper dataonoccurrenceofincestarefarlessclear-cutthanvan
on parent-offspring conflict, Trivers claims that his den Berghe allows. Anxious to rebutpublishedaccounts
model provides an account of adolescent resistance to of widespread incest as "sensationalistic," he seeks to
socialization. The root idea is that there should be some minimize the incidence of incest. Instead, van den
situationsinwhichitwillbeintheinterestsoftheparents' Berghe leans heavily on datafrom the kibbutz, purport
inclusive fitness ifa child behaves altruistically toward a ing to show that children reared in the same kibbutz
sibling. Parents can be expected to encourage more showed little inclination to "marry or make love to each
cooperation than it behooves their children to give, and other" (Shepher 1971; van den Berghe 1983). However,
Trivers concludes that this explains conflicts between this is to neglectconfoundingfactors, mostobviouslythe
parents and their adolescent offspring. influence ofa program ofkibbutz education, during the
I argue that detailed models ofthe situation can give relevant period, which stressed the importance ofchas
virtually any conclusions we want to obtain, depending tity(Kaffman 1977). Anothersourcethatvanden Berghe
ontheassumptionswemake. Thefirstpointtonoteisthat citesis thestudyof"minormarriages"inTaiwan(Wolf&
there have to be some mechanisms that lead to parental Huang1980). Inthiscase, acloselookatthedetailsofthe
encouragement and adolescent resistance, respectively. datareveals thatthere isa rivalsocioculturalexplanation
Mechanisms that lead to conflict in all situations are not for the lowered reproductive success in such marriages.
promising candidates for fitness-maximization, whereas The evidence about incest avoidance is also clouded by
those that are selective have to be very finely tuned the existence ofa genetic study (Spielman, Neel & Li
indeed. I elaborate these points byconstructingafamily 1977),unmentionedbyvandenBerghe,whichappearsto
ofmodels and showing that, as we vary the parameter show a relatively high amount of inbreeding in past
values, we can obtain any combination ofstrategies for Amerindianpopulations. Thus, Iclaim, wedonothavea
parentandchild. Second, Trivers'smodeltacitlyassumes clear picture ofwhether, in the absence ofsocial sanc
that we are treating a one-directional flow ofaid. Ifwe tions, peopleavoidcopulatingwiththosewithwhomthey
supposethatthereisroughsymmetrytothesituations, so have been reared.
thatthe childwho isencouragedto give today islikelyto Finally, itisnotclearthatdetailedevolutionarymodels
be a beneficiary tomorrow, then the children are effec woulddelivertheconclusionsthatvandenBerghewants.
tivelyengagedinaniteratedgameofprisoner'sdilemma. If the attempt to find an unrelated mate brings with
The results ofAxelrod and Hamilton (1981) tell us that it a high probability of death or serious damage, then
"tit-for-tat" is an ESS (evolutionarily stable strategy) for people may do better to stay home and copulate within
this game (see also Maynard Smith 1982 [and BBS 7(1) the family (Bengtsson 1978; May 1979). Moreover, van
1984]), so that the children should be expectedtoaccede den Berghe's own proposal about the possibilityofmax
toparentalpressure to cooperate. Finally, I showthat in imizingfitness insituationsofroyalsiblingincestappears
the particular example Trivers gives (a child resisting to be based on confusions about inclusive fitness. When
parental demands to do homework) the analysis Trivers theconfusionsareclearedawayandthedetailsareelabo
supplies does not fit. Moreover, the illustration draws rated, the conditions required for royal incest to be a
attention to a general point. Pop sociobiological models fitness-maximizingstrategyseemveryunlikelytoobtain.
can easilyintroduce evolutionary modelingin the wrong
place, focusing noton the adaptive value ofthe underly
ingdispositions tobehaviorbuton theparticularitemsof Alexander's program
behavior that are manifested in quite special circum
stances. The discussion ofAlexander's ideas (see below) Richard Alexander(1979)claims thatcontemporary Dar
underscores the importance ofthis error. winism provides "the first simple, general theory of
Finally, Chapter 8 takes a look at the example that humannaturewithahighlikelihoodofwidespreadaccep
some aficionados take to be the best application of so tance" (p. 12). However, his vision ofwhat a theory of
ciobiology to human behavior - the case ofincest avoid human nature is differs from that adopted by Wilson.
ance (Ruse 1982; Wilson in Shepher 1983). Van den Chapter 9 ofAmbition takes a close look at Alexander's
Berghehasarguedthathumanshaveanadaptivepropen program and at the work of some anthropologists who
sityto avoid copulatingwith those with whom they have have been influenced by his conception ofsociobiology.
beenreared(vanden Berghe 1980;1983;vanden Berghe Alexanderisquiteforthrightinclaimingthathis goalis
& Mesher 1980). He also suggests that in the rare in notthatofshowinghowourgenes setlimitstoourforms
stances in which sibling incest has been encouraged or ofsocial behavior and ourcultural institutions (1979; see
even prescribed, it can be understood as a fitness-max also Kurland1979). Indeed, hearguesthattheenterprise
imizing strategy. ofdiscoveringthelimitsofhumanbehaviorisself-defeat
I criticize van den Berghe's account of incest on a ing: The ideais thatwecouldnotidentifyalimitwithout
number of different grounds. First, there are serious simultaneously learning how to transcend it. Unfortu
problems about how to define incest, since there is a nately, this reassuring argument is specious, for the
whole range ofpotentiallyrelevantparticipants (siblings, simplereason thattheoreticalknowledgedoesnotalways
stepsiblings, unrelated children reared together) and a bring practical skill.
spectrum ofpotentially relevant forms ofbehavior (kiss Since Alexander disavows the most obvious way of
ing, fondling, full copulation, homosexual relations, and regarding Darwinism as the key to a theory ofhuman
BEHAVIORALAND BRAIN SCIENCES(1987) 10:1 67
Kitcher: Problems ofhuman sociobiology
nature, the first task must be to achieve an alternative ture would use in explaining the institution? Again, I
reading. Iconsidertwopossibilities. Ontheconservative think not.
interpretation, the task of sociobiology is to provide To appreciate the last point, we must recognize that
evolutionary explanations of human behavior that are although (other things being equal) relatives enhance
consistent with our everyday ideas about the proximate their inclusive fitnesses by helping one another, the
mechanismsofthebehavior. Historians, anthropologists, evolutionaryexplanation ofthis fact does not involve the
and ordinary people use a commonsense account of thesis thatinstitutingprimogenituremaximizesinclusive
human motivation to understand the doings ofothers. fitness. Itwould be folly to argue that the disposition to
Call this familiar picture folk psychology. Construed aidkin has beenfixed in usas aproximatemechanismfor
conservatively, Alexander's proposal is to provide evolu leading us to maximize our inclusive fitness through
tionaryexplanationsfor the presence in us ofthe mecha primogeniture. That argument sets the cart before the
nisms adduced by folk psychology. In short, the task of horse. We explain the institution in terms ofthe proxi
sociobiology would be to develop evolutionaryfolk psy mate mechanisms, and, ifwe want to pursue EFP, we
chology, or EFP. must give an evolutionary explanation ofthe presenceof
Alexander's claims might be more revolutionary. Per the proximate mechanisms. We do not achieve it by
hapsrecognizingthataform ofsocialbehaviormaximizes supposingthat those mechanisms werefavored byselec
the inclusivefitnesses ofthe participantscouldchallenge tion because they led to primogeniture, but by pointing
our prior conceptions of human motives and human to the far more general phenomenon that helping kin is
decision making. Themostradicalpossibilitywouldbeto likely to increaseinclusivefitness across abroad rangeof
suppose that there is some general, all-purpose mecha contexts.
nism for calculating the expected payoffsofthe available Chapter 9 continues by considering Alexander's dis
courses ofactionand to claim that this alwayscomes into cussion of the avunculate (1979; also Kurland 1979). I
playinthecausationofoursocialbehavior. Alessrevolu develop Alexander's qualitative account and Kurland's
tionary alternative would claim that particular propen more precise model ofwhy men might maximize their
sities, ofwhich we are normally unaware, incline us to inclusive fitness by investing in their sisters' children
actions that maximize inclusive fitness. For example, under conditions of paternity uncertainty. I argue that
Alexandermight suggestthattheways inwhich we treat there is a game-theoretic extension of the model that
ourrelativesaresofinely attuned tofitness maximization suggeststhattheavunculateislikelytocollapse, forthere
that we must not simply assume that we have a general are female strategies that can apparently invade the
propensity to love our kin, but a capacityfor calculating population and that would allow men a higher expected
exact coefficients ofrelationship and valuing people ac payoffif they invested in the children oftheir wives. I
cordingly. On either version, the pop sociobiological claim that this simple point reveals the fact that the
view ofhuman nature sees us as having hitherto unrec Kurland-Alexander analysis rests on undefended con
ognized mechanisms for directing fitness-maximizing straints, and that it is only by invoking these constraints
behavior. thatone cangenerate the conclusion that the avunculate
Chapter 9 considers Alexander's claims about the fit is a fitness-maximizing institution.
ness-maximizingcharacterofhuman social behaviorand Moreover, the explanation offered by Kurland and
their bearing on the conservative and the revolutionary Alexander runs into difficulties with the ethnographic
interpretations ofhis pop sociobiology. Alexander's gen record (difficulties that both writers acknowledge). The
eralstrategyis toassemblealistof"predictions"from his suggestionsforovercomingthesedifficultiesraisefurther
theory ofhuman nature and to considertwo examples in problems. Thus we have been given a problematic
some detail. I argue that his listof25 "predictions" does model, an admittedly incomplete ethnographic record
nothingtosupporthiscase.Thelistconsistsofasequence thatdoes containenoughinstances tocauseproblemsfor
of relatively banal facts about ourselves that are only the model, and, finally, some suggestionsfor responding
loosely connected with Alexander's central thesis. The tothedifficultiesthatareapparentlyintensionwithother
looseness offit is especially obvious when we consider favored pieces ofsociobiological work.
examples that appear to threaten the doctrine that hu Iclaimthatfolk psychologydoes better, andthatbanal '
mansbehavesoastomaximizetheirinclusivefitness, for, points about common human aspirations make the prac
in these cases, Alexander appeals to complications in tice of the avunculate comprehensible. Moreover, the
human social situations, complications that are routinely conservative interpretation ofAlexander's program, on
ignored when there is a rough fit between the behavior which the sociobiological studyisacontributionto EFP,
and some simple idea about how inclusive fitness is fares no better here than it did in the example of pri
maximized. mogeniture. Suppose it were true that the avunculate
The mostpromisingcaseon the listis the institutionof maximizes the inclusive fitness ofthose who practice it.
primogeniture. Wecaneasilydevise an argumentforthe Howwould thatfact bearon the evolutionofthe disposi
view that bequeathing the family fortune to the eldest tions, such as the desire for the welfare of one's close
childislikelytobefitness-maximizing. Buthowdoes this relatives, which(on thefolkpsychologicalstory)underlie
showusanythingimportantabouthumannature?Doesit the practice of the avunculate? It would be absurd to
offer a more refined account of people's behavior, sug proposethattheevolutionaryexplanationofthepresence
gesting hitherto unsuspected mechanisms and offering ofthese dispositions is that they have been favored by
more precise predictions? I think not. Does it make a selection in situations when paternity is uncertain.
contribution to EFP by increasing our understanding of The chapter concludes with a detailed look at two
thepropensities (suchas adesire to secure the welfareof examples from the anthropological literature in which
offspring) that afolk psychological accountofprimogeni- appeals to inclusivefitness maximizationaresupposedto
68 BEHAVIORALAND BRAIN SCIENCES (1987) 101