The idea that reflection on the processes of evolution might illuminate human

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1 J O H N D U P R EÂ Evolution and Gender The idea that reflection on the processes of evolution might illuminate human behaviour has been around almost since Darwin s announcement of the theory of evolution by natural selection. As long as this idea has been around, central to the agenda of the programme it introduced has been the explanation of differences in gender. The two sexes of non-human animals often display striking differences in both morphology and behaviour, and the explanation of these differences has been part of the general project of explaining biological phenomena by appeal to natural selection. Since human societies also exhibit systematic differences in the behaviour of men and women, it has seemed natural or even inevitable to many to extend this explanatory strategy to our own species. The major objection to this extension has been the claim that, although human societies do indeed universally display such differencesðdifferences that have been theorized under the general rubric of genderðthe precise articulation of these differences is extremely varied. Different cultures prescribe different gender-specific behaviour for men and women, and even within a particular culture there is often considerable latitude in these behavioural prescriptions, or even the possibility of major transgression. This seems to show at least that there is a lot more to the explanation of gender difference than simply an appeal to natural selection and its biological legacy. The perceived weight of these contrasting lines of thought has varied considerably in the years since Darwin s momentous reformulation of biology. In the middle of this century, in the aftermath of the horrors of Nazism, biological explanations of human behaviour were largely shunned. At the same time increased awareness of anthropological accounts of diverse gender systems motivated greater awareness of the force of the premises... Women: a cultural review Vol. 12. No. 1. ISSN print/issn online # 2001 Taylor & Francis Ltd DOI: /

2 10. WOMEN: A CULTURAL REVIEW underlying an argument against biological explanations of gender. The paradigm for this perception was of course the work of Margaret Mead, especially on the sexual practices of Samoans (Mead 1949). However, in the last few decades the pendulum has been swinging in the opposite direction. The landmark event for this change was the publication of Sociobiology: The New Synthesis by Edward O. Wilson in 1975, and the heated debate precipitated by the final chapter of that book in which Wilson advocated the extension of the evolutionary explanation of social behaviour to humans (Wilson 1975). The theoretical foundations for the specific theories about gender difference were laid by Robert Trivers s celebrated work on parental investment (1972). The relevant ideas became widely known, particularly in Britain, through the influence of Richard Dawkins s bestseller The Selfish Gene (1976). Evolutionary Stories about Gender The basic idea through which evolution is supposed to help us understand gender is a very simple one. The minimum parental investment in producing an offspring is typically much less for males than it is for females. Whereas a female (mammal, let us say) must minimally gestate and provide care for a few weeks, months or years, depending on the species, a male may successfully reproduce in the workðor even pleasureðof a few moments. If we consider the animal from the perspective of natural selection as, roughly speaking, acting to maximize its reproductive output, the situation facing males and females will be very different. Specific attempts at reproduction will be potentially much more significant to the female than the male. If there is a reasonable chance that the female will successfully rear the offspring on her own, and he believes that he has a good chance of finding other females to inseminate, the male will do his best to abandon this female and go off in search of the next. The female, on the other hand, has no such option, at least until she has gone some way towards rearing the present young. Her concerns will rather be trying to identify males who may offer some assistance with childcare or, in the likely event that there are no such males, looking for those males who can provide genes that will give her offspring the best chance of survival and reproductive success. It turns out that this simple story is able to generate a good deal of folk wisdom about human sexual relationships. Men, it predicts, will be constantly on the look-out for the next sexual partner and unlikely to be easily persuaded to take on the labour of raising the family. As Richard Dawkins graphically expresses it, `a male... can never get enough copulations with as many females as possible: the word excess has no meaning for a male (1976:176). They will be particularly anxious to pursue

3 EVOLUTION AND GENDER. 11 women perceived to be maximally fertile, which is to say, young. (According to a popular addendum to the theory, the preferred targets will also be curvaceous, with an ideal waist-to-hip ratio of 0.7. I ignore this curious complication here.) The middle-aged executive running off with his secretary (or professor with his graduate student) is, on this view, behaving in accord with the deepest biological imperative. There is, of course, a comparable elaboration of the story for females, or women, and one that, conveniently enough, also explains the possibly surprising fact that the secretaries or graduate students are often willing to run off with the middle-aged men. Females, as I have noted, will be concerned with resources or genes. The best way of acquiring the former, of course, is to look for successful men. And if there is a significant genetic component contributing to their success, this strategy will also tend to serve the latter end. Men often take some time to achieve command over resources, so women are often drawn to older men. More recent theory, however, presents a somewhat more alarming picture of women s psychology. Since resources and optimal genes cannot be guaranteed to go together, the best strategy would be to seek them from different sources. The most successful females would be those who secured a male with the greatest resources for the care of their young but also managed covertly to acquire the best genes on the side. This strategy is said to be very often observed in some species of birds, and the discovery that substantial proportions of human children do not share the genes of the men taken to be their fathers have led some to speculate that the strategy is also pursued by human females. Empirical research in which women claimed to be more likely to form relationships of various kinds with men dressed in expensive suits and Rolex watches than with the same men kitted out as Burger King employees are taken to support this general view of evolved female psychology (Buss 1994). Conversely, men claimed to be keen on sexual relationships with women pretty much regardless of their marks of social status. These conclusions have led, incidentally, to one of the more unsavoury directions in which this speculation has been pursued. All fertile women but only successful men, or perhaps men with indicators of exceptionally fine genes, will have value in the reproductive market place. Men with neither exceptional genes nor exceptional resources, however, will be excluded. It has been suggested, therefore, that for such men the best available reproductive strategy will be rape. Thus sexual violence as well as stereotypical gender roles appear as Darwinian adaptations. Needless to say, there are various objections to the claim that these evolutionary speculations provide good explanations for central features of human gender differences. Certainly they have nothing to say, for instanceð despite some wild speculationsðabout the prevalence of homosexuality. I

4 12. WOMEN: A CULTURAL REVIEW have discussed various of these objections in some detail elsewhere (Dupre 2000, 2001) but here I want to consider only one very general problem: how is the causal influence from natural selection supposed to operate in the production of actual behaviour? Edward O. Wilson s early writings on this topic were not very specific on the issue of mechanisms connecting natural selection to behaviour. It is generally assumed, however, that natural selection works only through the accumulation of genes. Natural selection for particular forms of behaviour, then, must work through the accumulation of genes that influence behaviour. No one imagines that genes directly manipulate the production of behaviour, of course. So genes that influence behaviour can only be genes that influence the production of brains that, in turn, tend to produce behaviour of the selectively favoured kind. Various powerful attacks on the sociobiology of Wilson and his followers in the decade after the appearance of Sociobiology (such as Lewontin, Rose and Kamin 1984 and Kitcher 1985) left the term `sociobiology in some disrepute, and a new generation of sociobiologists reinvented themselves in the mid- to late 1980s as `evolutionary psychologists. The definitive statement of the evolutionary psychologists viewpoint can be found in an anthology edited by Jerome Barkow, Leda Cosmides and John Tooby (Barkow et al. 1992), including a 120±page introduction by Tooby and Cosmides (Tooby and Cosmides 1992). The central point on which the evolutionary psychologists aimed to distance themselves from their sociobiologist precursors was their elaboration of a more detailed account of the links between natural selection and behaviour. Specifically, they argued that the human mind was to be seen as containing large numbers of `modules custom-built by natural selection for dealing with environmental situations of particular evolutionary significance. Thus in the present context there might be sexual-attractiveness-estimating modules, mate-desertion modules (for males), childcare modules (mainly for females), resource-assessment modules, perhaps rape modules and so on. It is this array of evolved psychological modules that evolutionary psychology offers as the primary explanation for human behaviour in general, and gender-specific behaviour in particular. It seems unlikely that there is anything here very different from what Edward O. Wilson imagined in 1975 but, whether that is so or not, there are enormous difficulties with the evolutionary psychological perspective. First and foremost, there is no evidence whatever for the existence of any of the modules that evolutionary psychologists hypothesize. Certainly evolutionary psychologists have done a fair amount of research on human dispositions to behaviour. David Buss (1994) has been the most prominent practitioner of such research in connection with human gender differences. But the inference to a specialized module generating the observed regularities is

5 EVOLUTION AND GENDER. 13 wholly speculative. It is invariably possible to propose alternative explanations for such regularities that depend rather on common environmental causes. And indeed Tooby and Cosmides (1992) defend their commitment to modules largely on the basis of a quite unconvincing quasi-transcendental argument that no other explanation can possibly work. However, I want to consider rather the extent to which the modular mind of evolutionary psychology can respond to the point emphasized at the beginning: the apparent variability of gender differences. The `Illusion of Variability The central response of evolutionary psychology to gender variability is to deny it. Human similarity, they allege, is much more fundamental than difference. Indeed, `the variable features of culture can be learned solely because of the existence of an encompassing universal human metaculture (Tooby and Cosmides 1992:92). Metaculture, it appears, is composed of shared assumptions. Hence the cultural anthropologist `could not understand or live within other human groups unless the inhabitants of those groups shared assumptions that were, in fact, very similar to those of the ethnographer. In some sense this is no doubt true. As philosophers such as Donald Davidson (1984:essays 10±12) have argued, interpretation of an alien culture must rely on the presupposition that many assumptions are shared. However the crucial question is what sort of assumptions these must be. Some such assumptionsðthat the world is composed of continuous things rather than time slices or undetached parts of things, or that it is possible to change the future but not the past, sayðhave little bearing on human nature. OthersÐsuch as that some plants and animals are good to eat or that jumping off cliffs is a bad ideaðdo have a bearing on human nature but not on any controversial aspect of human nature. It is not very plausible that learning to communicate with alien cultures requires that we and they share the assumption that women seek wealthy, high-status men or that women are most attractive with small waists and symmetrical features. In short, we might agree that there is a sense in which shared humanity is more fundamental than cultural variation, without lending the slightest encouragement to the project of evolutionary study for illuminating, for example, gender differences. A more helpful point on which Tooby and Cosmides insist is that we should not confuse the variable with the learned. `The claim that some phenomena are ``socially constructed only means that the social environment provided some of the inputs used by the psychological mechanisms of the individuals involved. With some qualms about the exact implications of the term `psychological mechanism I take this to be basically correct.

6 14. WOMEN: A CULTURAL REVIEW However, its proper interpretation takes us, I think to the heart of the matter. There is a curious feature of contemporary debates over human nature. On both sides of the debate it is mandatory to accuse one s opponent of assuming a crude dichotomy between nature and nurture. Everyone, apparently, agrees that no such a distinction is tenable. Everyone, on the contrary, embraces some kind of interactionism: humans develop as the result of a continuous interplay between causally efficacious features of their biology (for example, genes) and inputs from the environment. One s opponent is either a crude genetic determinist (the evolutionary psychologists) or a cultural determinist (supporters of what Tooby and Cosmides refer to as the Standard Social Sciences Model, the view that the human mind is a blank slate on which the environment writes). I mention this stereotypical aspect of the debate apologetically, because this is the point at which I shall accuse Tooby and Cosmides of assuming a crude nature/nurture dichotomy. I certainly do not mean to accuse Tooby and Cosmides of being genetic determinists, at least in the sense of holding that genes determine behaviour. Genes, on their view, determine `psychological mechanisms, and psychological mechanisms produce behaviour in ways that respond differentially to different environmental stimuli. So it is certainly fair to say that they have a properly interactionist understanding of the generation of behaviour. They are, however, genetic determinists when it comes to psychological mechanisms. The female mate-selection mechanism may be trained in one context to respond to Savile Row suits and Rolex watches, in another to large piles of Cowrie shells, but the basic mechanism is common to all human females. This determination of psychological mechanisms is, as far as I can see, not very plausible and certainly not backed by any serious argument. To explain the matter further, I must say more about what I mean by genetic determination. Although variability is not, as noted, a mark of cultural determinationðif by that is meant complete invariance with respect to internal factors such as geneticsðinvariability across different cultural contexts is, fairly obviously, evidence for the lack of causal relevance of culture. There are, of course, minimal environmental conditions for any human trait whatever, namely provision of the minimal requirements for human survival. And it is always possible that cultures just happen not to vary in respects that are relevant to a particular trait. But invariability of a trait is at least good evidence that variable cultural factors are not relevant to the production of the trait. This is the situation to which I refer, ignoring for now important qualifications about the centrality of genes, by the term `genetic determination. In this sense it is plausible to claim that the structure of the heart or the liver is largely genetically determined (though not wholly so, as we know from research on the effects of environments rich in saturated fat or alcohol on the development of these organs). And it is in this sense that

7 EVOLUTION AND GENDER. 15 Tooby and Cosmides clearly hold that psychological mechanisms are genetically determined. Recalling their remark about the social environment providing `some of the inputs used by the psychological mechanisms of the individuals involved it is pretty clear that the picture intended is of these psychological mechanisms as constants interacting with a variable environment. Having identified one point at which I want to differ fundamentally with the evolutionary psychologists programme, I can now say that it seems that there is no general reason why one should think of the mind in this biologically determined way and, moreover, that I take cultural variability to be evidence, though not decisive, that one should not. It may be helpful to consider a simpler human faculty than the mind: the one just mentioned, the liver. I do not actually know whether the liver is genetically determined in the sense just explained. Taking the liver to have the function of blood detoxification, one can imagine at least three strategies that Mother Nature might have followed in constructing such an organ. The cheapest policy, perhaps, would be to have an invariant structure capable of dealing with just those toxins commonly encountered in human blood streams. However, if the occurrence of toxins was unpredictable it would be useful to be able to make an all-purpose detoxifying organ that could deal with a large and indeterminate range of toxins. This could (perhaps) be a structure invariant across all healthy humans. A third option would be a trainable liver. This would be an organ that learned to detoxify whatever toxins it happened to encounter in the course of its development. This might run the risk of the organism being poisoned by unfamiliar substances before the liver had learned to deal with them, but would have the advantage of allowing the liver to become specialized in addressing the hazards that would in fact be commonly encountered. As I have said, I know little about which type of strategy actual livers employ (if any of the above). But the point of the parable should be obvious. The human mind is typically to be found in a moderately specific cultural context, but there are a large number of such contexts that different human minds find themselves in. Analogues of two of the strategies just distinguished seem possible. The second strategy, a universal mind capable of dealing with any cultural context is one possibility. This, I take it, is the allpurpose information processing machine greatly scorned by biological determinists. Perhaps they are right to scorn it. But the relevant alternative, I think, is an analogue to the third strategy, namely a mind that develops specific capacities for dealing with the particular culture it is born into. The disadvantageðthat such a mind may function poorly when introduced into an unfamiliar cultureðseems to accord with empirical experience of cultural translocation. But what seems clearly least desirable is any version of the first strategy, a universal mind specifically designed for a particular cultural

8 16. WOMEN: A CULTURAL REVIEW context. This, oddly enough, is exactly what evolutionary psychology proposes. In fact, they claim, our universal minds are specifically designed for Stone Age life on the African savannah. It is of course possible that the alleged invariability of life in our evolutionary past has saddled us with this wretchedly dysfunctional strategy. But being more optimistic about the adaptedness of human minds, and sceptical about the drearily homogeneous conditions that are said to have produced these atavistic bits of mental equipment, I see little reason to accept this pessimistic conclusion. Evidence 1 I have discussed this evidence in more detail elsewhere, and here will only describe the outlines of the problem. I have not argued that the perspective of evolutionary psychology is incoherent, only that it is conjectural and perhaps improbable. A plausible response is to conclude that one should then focus on the evidence. The reason it is so important to investigate these theoretical underpinnings is that when we do come to look at the evidence offered for evolutionary psychology it turns out that this is generally derisory. What constantly gives this evidence the appearance of significance is the assumption that the theoretical background is in broad outline unavoidable. 1 To begin with there is the question of how deep cultural diversity really is. As mentioned above in connection with `metaculture, evolutionary psychologists are inclined to minimize this diversity. The work of Margaret Mead, mentioned above as the locus classicus for anthropological accounts of gender diversity, is said to have been comprehensively refuted by Derek Freeman (1983). I lack the expertise to evaluate this dispute in any detail. But, as Tooby and Cosmides correctly point out, with regard to the degree of order and uniformity one observes, `one can get whichever answer one wants simply by choosing one frame of reference over another (Tooby and Cosmides 1992:44). If, for example, one chooses to define `marriage as any social institution according rights and responsibilities to cohabiting couples, one will discover that most human societies have a practice of marriage. The student of gender, on the other hand, may wish to make some more refined distinctions. But perhaps more interesting is the case of intracultural variation. No one seriously denies that gender specific behaviour is diversely implemented by the members of particular cultures. Not all sexual relations occur between wealthy and powerful men and young, curvaceous and symmetrical women. The most evolutionary psychologists could hope to demonstrate would be statistically significant tendencies to the kinds of behaviour they predict. In attempting to shape this sort of evidence to a universalizing programme, one can find textbook examples of what philosophers of science have referred to as ad hoc auxiliary assumptions: hypotheses for which the only evidence is

9 EVOLUTION AND GENDER. 17 that they would protect a favoured theory from its empirical refutation. For example, one authority on the evolution of sexual attractiveness, Bruce Ellis, responds to the unexpected observation that American women as well as men claim to find dominance an unattractive characteristic (Ellis 1992). Ellis suggests various explanations: (1) women may imagine that dominant men will tend to dominate them rather than other men; (2) they may be embarrassed to admit this preference; (3) they may prefer dominant men but be unconscious of their preference; (4) only high status men may fall within the bounds of their sexual imagination, and within this narrow class they are attracted to relatively lower status men, but absolutely high status men (282). Any of this is possible. But it would be hard to illustrate more clearly the ease with which such ad hoc hypotheses can be thought up or, consequently, the little reason we should have for taking them very seriously. It is entirely possible that the statistical tendencies discovered by evolutionary psychologists do indeed indicate biological tendencies. By this I mean, in parallel with the definition offered above of biological determinism, that biological factors are such that `mental machinery with certain characteristics will develop in people in a wide range of environments. But if we interpret psychological variability in the way I have suggested, as indicating the different psychological mechanisms that will result from different sequences of interactions between biological nature and environment, this should direct us to investigate more closely the processes of human development rather than simply attempt to explain away the deviations from an assumed essential norm. For such a perspective also entails that in other, perhaps currently less common, environments, different psychological traits will develop. And of course, if one thinks that the prevalence of certain sets of psychological dispositions in human populations will tend to produce societies in which humans are more likely to flourish, this perspective will hold out genuine possibilities for finding out how to make human life better. Moving on from the Stone Age Contemporary attempts to understand human behaviour in general, and gender-differentiated behaviour in particular, as the outcome of universal psychological mechanisms evolved in the Stone Age is based on a thoroughly unconvincing theoretical foundation. A more sophisticated understanding of biology suggests a focus on development as a cascade of interactions between biological nature and cultural context with psychological outcomes that cannot be predicted merely by reflection on imaginative recreations of Stone Age life. As my previous remarks should also make clear, this is a much more

10 18. WOMEN: A CULTURAL REVIEW optimistic view of the human condition. It emphasizes development and the possibility of change, not only for individuals but also for society. And I take it that most students of gender would hold that such change might produce better societies for individuals to live in. I do not suggest that these more optimistic conclusions provide epistemologically good reasons for accepting the perspective I have presented. I would rather emphasize that we are still very ignorant of the processes of human development. However, this ignorance should make us extremely reluctant to accept a purely speculative perspective that presents the current state of things as, within narrowly circumscribed limits, an inevitable consequence of our evolutionary history. Bibliography Barkow, Jerome H., Cosmides, Leda and Tooby, John (eds) (1992), The Adapted Mind, New York: Oxford University Press. Buss, David (1994), The Evolution of Desire, New York: Basic Books. Davidson, Donald (1984), Inquiries into Truth and Interpretation, Oxford: Oxford University Press. Dawkins, Richard (1976), The Selfish Gene, Oxford: Oxford University Press. DupreÂ, John (2000), `What the Theory of Evolution Can t Tell Us, Critical Quarterly 42, 18±34. ÐÐ (2001), Human Nature and the Limits of Science, Oxford: Oxford University Press. Ellis, Bruce J. (1992), `The Evolution of Sexual Attraction: Evaluative Mechanisms in Women, in Barkow et al. (1992), pp. 267±88. Freeman, Derek (1983), Margaret Mead and Samoa: The Making and Unmaking of an Anthropological Myth, Cambridge, MA and London: Harvard University Press. Kitcher, Philip (1985), Vaulting Ambition: Sociobiology and the Quest for Human Nature, Cambridge, MA and London: MIT Press. Lewontin, Richard, Rose, Steven and Kamin, Leon J. (1984), Not in Our Genes: Biology, Ideology and Human Nature, New York: Pantheon Books. Mead, Margaret (1949), Male and Female, New York: Morrow. Tooby, John and Cosmides, Leda (1992), `The Psychological Foundations of Culture, in Barkow et al. (1992), pp. 19±136. Trivers, Robert (1972), `Parental Investment and Sexual Selection, in B. Campbell (ed.), Sexual Selection and the Descent of Man, New York: Aldine de Gruyter, pp. 136±79. Wilson, Edward O. (1975), Sociobiology: The New Synthesis, Cambridge, MA and London: Harvard University Press.