Testosterone Rex Read online

  When we think of men and women in this complementary way, it’s intuitive to look for a single, powerful cause that creates this divide between the sexes. And if you’re thinking right now of a hormone beginning with the letter T, you’re not alone. Testosterone has long featured prominently in explanations of the differences between the sexes, and continues to do so. For example, University of Cambridge neuroscientist Joe Herbert’s recent book Testosterone: Sex, Power, and the Will to Win leaves readers at no risk of underestimating its potency:

  At the end of any discussion of the impact of testosterone on the history of mankind in all its wide-reaching and powerful complexity, a simple fact remains: without testosterone there would be no humans to have a history.22

  Now there’s a conclusion to inspire the reverence the testicle deserves… or at least until you realize that the same fact applies to oestrogen, carbon, and even that dullest of elements, nitrogen. But still—Sex! Power! The will to win! As Herbert explains, these are exactly the masculine qualities that, according to received wisdom regarding our evolutionary past, were so necessary for male reproductive success.23 The testosterone surge in males during gestation is critical for the development of the male reproductive gear. The sustained increase in testosterone at pubescence brings about sperm production and secondary sexual characteristics like increased muscle mass, facial hair, and broad shoulders. Wouldn’t it make sense if testosterone also made men masculine,24 creating a psychological wedge that makes men like this, while its minimal presence in females helps to make women like that? As the hormonal essence of masculinity, testosterone would ensure that the desire for sex, the drive for power, and the will to win develop far more strongly in the sex for whom it was reproductively beneficial in our evolutionary past.

  We all know what this means for sex equality in the workplace, given the much higher average levels of testosterone in men than women. Men’s wider range of reproductive possibility means that “the entire life history strategy of males is a higher-risk, higher-stakes adventure than that of females,” as one scholar put it.25 So what does it mean for hopes of equality if testosterone fuels the appetite for adventure? Of course, we should value the special qualities that arise from women’s low-risk, low-stakes approach to life. As world economies struggle to recover from the reckless risk taking that brought about the global financial crisis, commentators ask if there is “too much testosterone” on Wall Street,26 calling for more senior women in finance. To a woman, after all, with the merest dribble of testosterone coursing through her bloodstream, subprime mortgages and complex credit derivatives will not have the same irresistible appeal. But here’s the other side of that coin. If, thanks to the hand of evolution and implemented by testosterone, one sex is biologically more predisposed to want to take risks and get ahead, then it simply stands to reason that this is the sex that will be more eager to, say, take on the gamble of entrepreneurship, compete in Formula 1, or aspire to a powerful status that every day brings the heady possibility of barking the words “Jones—you’re fired!” As Dupré explains the implications:

  If status-seeking is shown to be an adaptation for male reproductive success, we have finally located the biological reason for the much lower status achieved by women. Let’s leave the men to pursue status while the women devote themselves to the important business of staying young.27

  It’s true that we don’t, as a rule, tend to think that the scientific facts of nature dictate how things should be. Just because a scientist says that something is “natural”—like male aggression or rape—obviously doesn’t mean we have to condone, support, or prescribe it. But that doesn’t mean that science has nothing to contribute to societal debates or aspirations.28 Although scientific claims don’t tell us how our society ought to be, that being the job of our values, they can give us strong hints as to how to fulfil those values, and what kind of arrangements are feasible.29 As Macquarie University philosopher Jeanette Kennett points out, if an egalitarian society isn’t “a genuine possibility for creatures like us… then, on the basis that ought implies can, egalitarian prescriptions and ideals are undermined.”30 If it’s typically only in male nature to play with certain kinds of toys, to want to work in particular kinds of occupations, to be willing to make the family sacrifices, and to take the necessary risks to get to the top, then that surely tells us something about what kind of society it’s reasonable to hope for and aspire to. Stoet, for example, takes pains to reassure that his conclusions about the lingering impact of our evolutionary past on girls’ interest in biology or engineering “does of course not mean that women in modern society should stick with traditional roles.” He emphasizes that people should be free to make counter-stereotypical career choices. But he is also of the view that this opportunity will never be taken up with any great regularity, and that initiatives to equalize women’s participation in higher-paying STEM careers “deny human biology and nature.”31

  This statement reflects a heavy responsibility shouldered by those who take this view of the sexes: to be the messenger of unwelcome but necessary truths. The principle of sex equality—that no one should be denied an opportunity simply on the basis of the genitalia they happen to have stowed in their undies—is reasonably well entrenched in Western, contemporary societies. True, the members of gentlemen’s clubs were apparently taking a long, deep nap when that particular shift in social attitudes and legislation took place; but most of us get it, and the principle is enshrined in equal-opportunity legislation. But if the sexes are essentially different, then equality of opportunity will never lead to equality of outcome. We’re told that “if the various workplace and non-workplace gaps could be distilled down to a single word, that word would not be ‘discrimination’ but ‘testosterone’”;32 that evolved sex differences in risk preferences are “one of the pre-eminent causes of gender difference in the labor market”;33 and that rather than worrying about the segregated pink and blue aisles of the toy store we should respect the “basic and profound differences”34 in the kinds of toys boys and girls like to play with, and just “let boys be boys, let girls be girls.”35

  This is Testosterone Rex: that familiar, plausible, pervasive, and powerful story of sex and society. Weaving together interlinked claims about evolution, brains, hormones, and behaviour, it offers a neat and compelling account of our societies’ persistent and seemingly intractable sex inequalities. Testosterone Rex can appear undefeatable. Whenever we discuss the worthy topic of sex inequalities and what to do about them, it is the giant elephant testicles in the room. What about our evolved differences, the dissimilarities between the male brain and the female brain? What about all that male testosterone?

  But dig a little deeper and you will find that rejecting the Testosterone Rex view doesn’t require denial of evolution, difference, or biology. Indeed, taking them into account is the basis of the rejection. As this book shows, Testosterone Rex gets it wrong, wrong, and wrong again. Contemporary scientific understanding of the dynamics of sexual selection, of sex effects on brain and behaviour, of testosterone-behaviour relations, and of the connection between our evolutionary past and our possible futures, all undermine the Testosterone Rex view.

  There is no dispute that natural selection shaped our brains as well as our bodies. If there are any feminist creationists out there—it seems like an unlikely combination of worldviews—I can attest that I’m not one myself. But as the first part of this book, “Past,” explains, the familiar “Biological Big Picture” version of sexual selection is now looking decidedly vintage. Decades of research in evolutionary biology have destabilized the key tenets once thought to apply universally across the animal kingdom, whereby arduous, low-investing males compete for coy, caring, high-investing females. The sexual natural order turns out to be surprisingly diverse, and we also bring our own uniquely human characteristics to the sexual selection story. For many years now, science has been rewriting and humanizing this evolutionary account: not much remains of the old
tale at the heart of Testosterone Rex, as the first three chapters show.

  “Past” razes old assumptions that universal principles of sexual selection inexorably gave rise to the evolution of two kinds of human nature, female and male. This clears the way for the second part, “Present,” to continue to build the case for the same conclusion, beyond sexuality. Needless to say, these days we all agree that “nature” and “nurture” interact in our development. But in the interactionism of the Testosterone Rex perspective, biological sex is “a basic, pervasive, powerful, and direct cause of human outcomes.”36 Sex is fundamental, so that story goes. It is the timeless, unchanging seed from which either a male or female developmental programme unfurls. Experience plays a secondary role in the individual’s developmental journey to a male brain and male nature, or to a female brain and female nature. Of course there is variability—not all men are identical, nor are all women. But amid all the “noise” of individual differences, a male or female “essence” can be extracted: characteristics of maleness and femaleness that are natural, immutable, discrete, historically and cross-culturally invariant, and grounded in deep-seated, biological factors.37 Whenever we say that “boys will be boys,” or accuse progressive interventions of trying to “go against nature” we invoke the assumption that there are such evolutionarily intended outcomes or “essences.”38

  But as Chapters 4 and 5 show, while the genetic and hormonal components of sex certainly influence brain development and function—we are not asexual blank slates—sex is just one of many interacting factors. We are an adapted species of course, but also unusually adaptable. Beyond the genitals, sex is surprisingly dynamic, and not just open to influence from gender constructions, but reliant on them. Nor does sex inscribe us with male brains and female brains, or with male natures and female natures. There are no essential male or female characteristics—not even when it comes to risk taking and competitiveness, the traits so often called on to explain why men are more likely to rise to the top.

  So where does that leave testosterone? How does it create masculinity, if there’s no one way of being a man, no common masculine core? Testosterone affects our brain, body, and behaviour. But it is neither the king nor the kingmaker—the potent, hormonal essence of competitive, risk-taking masculinity—it’s often assumed to be, as Chapter 6 explains. So while it’s probably fair to say that it really was mostly men who brought about the global financial crisis, the currently fashionable contention that “testosterone did it” and that therefore more “endocrine diversity” will save us,39 is an excellent example of what happens when flawed Testosterone Rex thinking is applied to research and public debate, as Chapter 7 concludes.

  So what should we make of—do with—this new and evolving scientific understanding of the relations between sex and society?

  The final part of the book, “Future,” looks ahead. The death of Testosterone Rex, and the arrival of its scientific successor, should transform how we think about the prospects for social change. No longer can we assume that to decree sex differences “biological,” “innate,” cross-culturally universal, or manifestations of sexually selected adaptations, is to pronounce us stuck with them, as the last chapter explains. So what, as a society, do we want?

  NO DOUBT TESTOSTERONE REX will survive the savaging it receives in this book, and—like a taxidermied family dog that persists past its natural life span—continue to linger on in the public and scientific imagination. However, hopefully it will be left looking gravely injured. Or at the very least a bit nibbled.

  But seriously, Testosterone Rex is extinct. It misrepresents our past, present, and future; it misdirects scientific research; and it reinforces an unequal status quo. It’s time to say good-bye, and move on.

  A NOTE ABOUT TERMINOLOGY

  _____

  A WHILE AGO, MY YOUNGER CHILD GROUND TO A HALT IN A homework assignment because he wasn’t sure whether to use the word “sex” or “gender” to describe a school-camp exercise in which every boy was paired with a girl.

  “Well!” I exclaimed gleefully when he posed the question, quietly thrilling with excitement to have been presented with such a perfect teachable feminist moment. “That’s a very interesting question, Olly. Let me try to explain.” At these words, Olly’s older brother let out a small gasp. If you can imagine the faces of onlookers had the Little Dutch Boy suddenly removed his finger from the hole in the dyke, you will have a rough idea of his expression.

  Ignoring this look with quiet dignity, I began my sermon on the principles of terminology, but was almost immediately interrupted.

  “Just tell me which, Mum,” my son said impatiently. “I’ve got multiplication homework to do as well. Is it ‘sex’ or ‘gender’?”

  HIS UNCERTAINTY ISN’T SURPRISING. From the late 1970s, the word “gender” began to be used as a way of drawing a distinction between biological sex, and the masculine and feminine attributes and status that a society ascribes to being male or female. The idea was that by referring to “gender” you highlight the role of these social constructions—what society makes it mean to be male or female—in creating disparities between the sexes, as opposed to the relentless unfurling of biologically determined male and female natures.1 But this approach was short-lived. From about the 1980s onwards, the word “gender” also began to be used in place of “sex” as a way of referring to whether an individual is biologically male or female, including even nonhuman animals.2 These days, for example, surveys regularly ask you to identify your “gender,” even though typically the expectation is that your answer will be based on whether you have a vagina or a penis, rather than any gendered psychic qualities or preferences. The person processing your credit card application will not appreciate it if, instead of checking one of the two boxes, you make annotations to the effect that in some ways your gender is male, but in other, no less important respects, it’s female. This shift in usage has therefore robbed the word “gender” of its original meaning and function.3 In its place, some feminist scientists now use terms like “sex/gender” or “gender/sex,” to emphasize that when you compare the sexes you are always looking at the product of an inextricable mix of biological sex and social gender constructions.4 But while this makes good sense (as Chapters 4 and 6 make clear), it’s not particularly conducive to a smooth reading experience. For this reason, I use “sex” when referring to comparisons based on the categories of biological sex, and “gender” to refer to the social ascriptions.

  In a second sacrifice of scholarly pedantry for the sake of readability, I use the word “promiscuous” (rather than more technical and precise terms like “polygynous,” “extra-dyadic coupling,” “polyandrous,” and “multiply mating”), despite this being a term that is coming to be frowned upon in evolutionary biology.5 While “promiscuous” is a highly value-laden term, no moral judgment whatsoever is implied by its application here. Not even for those slutty sandpipers featured in the chapter that follows.6

  PART ONE

  PAST

  CHAPTER 1

  FLIES OF FANCY

  BACK IN THE MISTS OF TIME THAT THANKFULLY CAST A HAZE over my dating career, I became entangled with a man who drove a Maserati. When I let this slip to my mother, she responded in the unnaturally bright tone of voice she uses whenever, in deference to my technical state of adulthood, she wishes to disguise the fact that she thinks I have made a decision that will lead inexorably to disaster. “Fancy, a Maserati!” she exclaimed. “Does he have many girlfriends?”

  The unsubtly implied connection has an interesting scientific history.1 In the middle of the last century, the British biologist Angus Bateman carried out a series of experiments with fruit flies. They would eventually become the wellspring of a flood of claims about the psychological differences that have evolved between women and men. If you have ever come across the idea that men drive Maseratis for the same reason that peacocks grow elaborately ornamental tails, then you have been touched by the ripples of this landmark stud
y. Bateman’s research was inspired by Darwin’s theory of sexual selection, which was a much debated subtheory within Darwin’s widely accepted theory of natural selection. (Natural selection is the process whereby the frequency of different versions of a heritable trait change over time, due to some varieties of a trait leading to greater reproductive success than others.) Sexual selection theory was, in part, an attempt to make sense of the mystery of why the males of many species display extravagantly showy characteristics, like the peacock tail. These phenomena demanded an explanation because they were so awkward for Darwin’s theory of natural selection. After all, if a primary goal of your life is to avoid being eaten by another animal, then a large, eye-catching, wind-dragging, feathered rear sail is not an asset.

  Darwin’s explanation drew on richly detailed observations of animals and their mating habits. (As one Nature journalist observed of that period of history, “despite the Victorians’ reputation for prudishness… there were few places in the world where courting animals could escape the note-taking naturalist.”)2 These field studies gave rise to Darwin’s famous observation in The Descent of Man, and Selection in Relation to Sex that the cause of males’ deviation from the female form

  seems to lie in the males of almost all animals having stronger passions than the females. Hence it is the males that fight together and sedulously display their charms before the female.3

  On the fighting side, more formally known as intrasexual competition, Darwin proposed that some characteristics (like an imposingly grand size or an intimidatingly large pair of antlers) are usually selected for more strongly in males. This is because these kinds of features increase a male’s reproductive advantage by enhancing his ability to fight against other males for access to females. On the other hand, more whimsical characteristics—like a splendid plumage, a tasteful odour, or an intricate song—have their positive effect on reproductive success by boosting the male’s appeal as a mate for the female. This dynamic is termed intersexual competition.