The most curious part of the thing was, that the trees and the other things round them never changed their places at all: however fast they went, they never seemed to pass anything. “I wonder if all the things move along with us?” thought poor puzzled Alice. And the Queen seemed to guess her thoughts, for she cried, “Faster! Don’t try to talk!”
—Lewis Carroll, Through the Looking-Glass
When a surgeon cuts into a body, he knows what he will find inside. If he is seeking the patient’s stomach, for example, he does not expect to find it in a different place in every patient. All people have stomachs, all human stomachs are roughly the same shape, and all are found in the same place. There are differences, no doubt. Some people have unhealthy stomachs; some have small stomachs; some have slightly misshapen stomachs. But the differences are tiny compared with the similarities. A vet or a butcher could teach the surgeon about a much greater variety of different stomachs: big, multichambered cow stomachs; tiny mouse stomachs; somewhat human looking pig stomachs. There is, it is safe to say, such a thing as the typical human stomach, and it is different from a nonhuman stomach.
It is the assumption of this book that there is also, in the same way, a typical human nature. It is the aim of this book to seek it. Like the stomach surgeon, a psychiatrist can make all sorts of basic assumptions when a patient lies down on the couch. He can assume that the patient knows what it means to love, to envy, to trust, to think, to speak, to fear, to smile, to bargain, to covet, to dream, to remember, to sing, to quarrel, to lie. Even if the person were from a newly discovered continent, all sorts of assumptions about his or her mind and nature would still be valid. When, in the 1930s, contact was made with New Guinea tribes hitherto cut off from the outside world and ignorant of its existence, they were found to smile and frown as unambiguously as any Westerner, despite 100,000 years of separation since they last shared a common ancestor. The “smile” of a baboon is a threat; the smile of a man is a sign of pleasure: It is human nature the world over.
That is not to deny the fact of culture shock. Sheeps’ eyeball soup, a shake of the head that means yes, Western privacy, circumcision rituals, afternoon siestas, religions, languages, the difference in smiling frequency between a Russian and an American waiter in a restaurant—there are myriad human particulars as well as human universals. Indeed, there is a whole discipline, cultural anthropology, that devotes itself to the study of human cultural differences. But it is easy to take for granted the bedrock of similarity that underlies the human race—the shared peculiarities of being human.
This book is an inquiry into the nature of that human nature. Its theme is that it is impossible to understand human nature without understanding how it evolved, and it is impossible to understand how it evolved without understanding how human sexuality evolved. For the central theme of our evolution has been sexual.
Why sex? Surely there are features of human nature other than this one overexposed and troublesome procreative pastime. True enough, but reproduction is the sole goal for which human beings are designed; everything else is a means to that end. Human beings inherit tendencies to survive, to eat, to think, to speak, and so on. But above all they inherit a tendency to reproduce. Those of their predecessors that reproduced passed on their characteristics to their offspring; those that remained barren did not. Therefore, anything that increased the chances of a person reproducing successfully was passed on at the expense of anything else. We can confidently assert that there is nothing in our natures that was not carefully “chosen” in this way for its ability to contribute to eventual reproductive success.
This seems an astonishingly hubristic claim. It seems to deny free will, ignore those who choose chastity, and portray human beings as programmed robots bent only on procreation. It seems to imply that Mozart and Shakespeare were motivated only by sex. Yet I know of no other way that human nature can have developed except by evolution, and there is now overwhelming evidence that there is no other way for evolution to work except by competitive reproduction. Those strains that reproduce persist; those that do not reproduce die out. The ability to reproduce is what makes living things different from rocks. Besides, there is nothing inconsistent with free will or even chastity in this view of life. Human beings, I believe, thrive according to their ability to take initiatives and exercise individual talent. But free will was not created for fun; there was a reason that evolution handed our ancestors the ability to take initiatives, and the reason was that free will and initiative are means to satisfy ambition, to compete with fellow human beings, to deal with life’s emergencies, and so eventually to be in a better position to reproduce and rear children than human beings who do not reproduce. Therefore, free will itself is any good only to the extent that it contributes to eventual reproduction.
Look at it another way: If a student is brilliant but terrible in examinations—if, say, she simply collapses with nervousness at the very thought of an exam—then her brilliance will count for nothing in a course that is tested by a single examination at the end of the term. Likewise, if an animal is brilliant at survival, has an efficient metabolism, resists all diseases, learns faster than its competitors, and lives to a ripe old age, but is infertile, then its superior genes are simply not available to its descendants. Everything can be inherited except sterility. None of your direct ancestors died childless. Consequently, if we are to understand how human nature evolved, the very core of our inquiry must be reproduction, for reproductive success is the examination that all human genes must pass if they are not to be squeezed out by natural selection. Hence I am going to argue that there are very few features of the human psyche and nature that can be understood without reference to reproduction. I begin with sexuality itself. Reproduction is not synonymous with sex; there are many asexual ways to reproduce. But reproducing sexually must improve an individual’s reproductive success or else sex would not persist. I end with intelligence, the most human of all features. It is increasingly hard to understand how human beings came to be so clever without considering sexual competition.
What was the secret that the serpent told Eve? That she could eat a certain fruit? Pah. That was a euphemism. The fruit was carnal knowledge, and everybody from Thomas Aquinas to Milton knew it. How did they know it? Nowhere in Genesis is there even the merest hint of the equation: Forbidden fruit equals sin equals sex. We know it to be true because there can only be one thing so central to mankind. Sex.
OF NATURE AND NURTURE
The idea that we were designed by our past was the principal insight of Charles Darwin. He was the first to realize that you can abandon divine creation of species without abandoning the argument from design. Every living thing is “designed” quite unconsciously by the selective reproduction of its own ancestors to suit a particular life-style. Human nature was as carefully designed by natural selection for the use of a social, bipedal, originally African ape as human stomachs were designed for the use of an omnivorous African ape with a taste for meat.
That starting point will already have irritated two kinds of people. To those who believe that the world was made in seven days by a man with a long beard and that therefore human nature cannot have been designed by selection but by an Intelligence, I merely bid a respectful good day. We have little common ground on which to argue because I share few of your assumptions. As for those who protest that human nature did not evolve, but was invented de novo by something called “culture,” I have more hope. I think I can persuade you that our views are compatible. Human nature is a product of culture, but culture is also a product of human nature, and both are the products of evolution. This does not mean that I am going to argue that it is “all in our genes.” Far from it. I am vigorously going to challenge the notion that anything psychological is purely genetic, and equally vigorously challenge the assumption that anything universally human is untainted by genes. But our “culture” does not have to be the way it is. Human culture could be very much more varied and surprising than it is. Our closest relatives, the chimpanzees, live in promiscuous societies in which females seek as many sexual partners as possible and a male will kill the infants of strange females with whom he has not mated. There is no human society that remotely resembles this particular pattern. Why not? Because human nature is different from chimp nature.
If this is so, then the study of human nature must have profound implications for the study of history, sociology, psychology, anthropology, and politics. Each of those disciplines is an attempt to understand human behavior, and if the underlying universals of human behavior are the product of evolution, then it is vitally important to understand what the evolutionary pressures were. Yet I have gradually come to realize that almost all of social science proceeds as if 1859, the year of the publication of the Origin of Species, had never happened; it does so quite deliberately, for it insists that human culture is a product of our own free will and invention. Society is not the product of human psychology, it asserts, but vice versa.
That sounds reasonable enough, and it would be splendid for those who believe in social engineering if it were true, but it is simply not true. Humanity is, of course, morally free to make and remake itself infinitely, but we do not do so. We stick to the same monotonously human pattern of organizing our affairs. If we were more adventurous, there would be societies without love, without ambition, without sexual desire, without marriage, without art, without grammar, without music, without smiles—and with as many unimaginable novelties as are in that list. There would be societies in which women killed each other more often than men, in which old people were considered more beautiful than twenty-year-olds, in which wealth did not purchase power over others, in which people did not discriminate in favor of their own friends and against strangers, in which parents did not love their own children.
I am not saying, like those who cry, “You can’t change human nature, you know,” that it is futile to attempt to outlaw, say, racial persecution because it is in human nature. Laws against racism do have an effect because one of the more appealing aspects of human nature is that people calculate the consequences of their actions. But I am saying that even after a thousand years of strictly enforced laws against racism, we will not one day suddenly be able to declare the problem of racism solved and abolish the laws secure in the knowledge that racial prejudice is a thing of the past. We assume, and rightly, that a Russian is just as human after two generations of oppressive totalitarianism as his grandfather was before him. But why, then, does social science proceed as if it were not the case, as if people’s natures are the products of their societies?
It is a mistake that biologists used to make, too. They believed that evolution proceeded by accumulating the changes that individuals gathered during their lives. The idea was most clearly formulated by Jean-Baptiste Lamarck, but Charles Darwin sometimes used it, too. The classic example is a blacksmith’s son supposedly inheriting his father’s acquired muscles at birth. We now know that Lamarckism cannot work because bodies are built from cakelike recipes, not architectural blueprints, and it is simply impossible to feed information back into the recipe by changing the cake.1 But the first coherent challenge to Lamarckism was the work of a German follower of Darwin named August Weismann, who began to publish his ideas in the 1880s.2 Weismann noticed something peculiar about most sexual creatures: Their sex cells—eggs and sperm—remained segregated from the rest of the body from the moment of their birth. He wrote: “I believe that heredity depends upon the fact that a small portion of the effective substance of the germ, the germ-plasm, remains unchanged during the development of the ovum into an organism, and that this part of the germ-plasm serves as a foundation from which germ-cells of the new organism are produced. There is, therefore, continuity of the germ-plasm from one generation to another.”3
In other words, you are descended not from your mother but from her ovary. Nothing that happened to her body or her mind in her life could affect your nature (though it could affect your nurture, of course—an extreme example being that her addiction to drugs or alcohol might leave you damaged in some nongenetic way at birth). You are born free of sin. Weismann was much ridiculed for this in his lifetime and little believed. But the discovery of the gene and of the DNA from which it is made and of the cipher in which DNA’s message is written have absolutely confirmed his suspicion. The germ-plasm is kept separate from the body.
Not until the 1970s were the-full implications of this realized. Then Richard Dawkins of Oxford University effectively invented the notion that because bodies do not replicate themselves but are grown, whereas genes do replicate themselves, it inevitably follows that the body is merely an evolutionary vehicle for the gene, rather than vice versa. If genes make their bodies do things that perpetuate the genes (such as eat, survive, have sex, and help rear children), then the genes themselves will be perpetuated. So other kinds of bodies will disappear. Only bodies that suit the survival and perpetuation of genes will remain.
Since then, the ideas of which Dawkins was an early champion have changed biology beyond recognition. What was still—despite Darwin—essentially a descriptive science has become a study of function. The difference is crucial. Just as no engineer would dream of describing a car engine without reference to its function (to turn wheels), so no physiologist would dream of describing a stomach without reference to its function (to digest food). But before, say, 1970, most students of animal behavior and virtually all students of human behavior were content to describe what they found without reference to a function. The gene-centered view of the world changed this for good. By 1980 no detail of animal courtship mattered unless it could be explained in terms of the selective competition of genes. And by 1990 the notion that human beings were the only animals exempt from this logic was beginning to look ever more absurd. If man has evolved the ability to override his evolutionary imperatives, then there must have been an advantage to his genes in doing so. Therefore, even the emancipation from evolution that we so fondly imagine we have achieved must itself have evolved because it suited the replication of genes.
Inside my skull is a brain that was designed to exploit the conditions of an African savanna between 3 million and 100,000 years ago. When my ancestors moved into Europe (I am a white European by descent) about 100,000 years ago, they quickly evolved a set of physiological features to suit the sunless climate of northern latitudes: pale skin to prevent rickets, male beards, and a circulation relatively resistant to frostbite. But little else changed: Skull size, body proportions, and teeth are all much the same in me as they were in my ancestors 100,000 years ago and are much the same as they are in a San tribesman from southern Africa. And there is little reason to believe that the gray matter inside the skull changed much, either. For a start, 100,000 years is only three thousand generations, a mere eye blink in evolution, equivalent to a day and a half in the life of bacteria. Moreover, until very recently the life of a European was essentially the same as that of an African. Both hunted meat and gathered plants. Both lived in social groups. Both had children dependent on their parents until their late teens. Both used stone, bone, wood, and fiber to make tools. Both passed wisdom down with complex language. Such evolutionary novelties as agriculture, metal, and writing arrived less than three hundred generations ago, far too recently to have left much imprint on my mind.
There is, therefore, such a thing as a universal human nature, common to all peoples. If there were descendants of Homo erectus still living in China, as there were a million years ago, and those people were as intelligent as we are, then truly they could be said to have different but still human natures.4 They might perhaps have no lasting pair bonds of the kind we call marriage, no concept of romantic love, and no involvement of fathers in parental care. We could have some very interesting discussions with them about such matters. But there are no such people. We are all one close family, one small race of the modern Homo sapiens people who lived in Africa until 100,000 years ago, and we all share the nature of that beast.
Just as human nature is the same everywhere, so it is recognizably the same as it was in the past. A Shakespeare play is about motives and predicaments and feelings and personalities that are instantly familiar. Falstaff’s bombast, Iago’s cunning, Leontes’s jealousy, Rosalind’s strength, and Malvolio’s embarrassment have not changed in four hundred years. Shakespeare was writing about the same human nature that we know today. Only his vocabulary (which is nurture, not nature) has aged. When I watch Anthony and Cleopatra, I am seeing a four-hundred-year-old interpretation of a two-thousand-year-old history. Yet it never even occurs to me that love was any different then from what it is now. It is not necessary to explain to me why Anthony falls under the spell of a beautiful woman. Across time just as much as across space, the fundamentals of our nature are universally and idiosyncratically human.
THE INDIVIDUAL IN SOCIETY
Having argued that all human beings are the same, that this book is about their shared human nature, I shall now seem to argue the opposite. But I am not being inconsistent.
Human beings are individuals. All individuals are slightly different. Societies that treat their constituent members as identical pawns soon run into trouble. Economists and sociologists who believe that individuals will usually act in their collective rather than their particular interests (“From each according to his ability, to each according to his needs”5 versus “Devil take the hindmost”) are soon confounded. Society is composed of competing individuals as surely as markets are composed of competing merchants; the focus of economic and social theory is, and must be, the individual. Just as genes are the only things that replicate, so individuals, not societies, are the vehicles for genes. And the most formidable threats to reproductive destiny that a human individual faces come from other human individuals.
It is one of the remarkable things about the human race that no two people are identical. No father is exactly recast in his son; no daughter is exactly like her mother; no man is his brother’s double, and no woman is a carbon copy of her sister—unless they are that rarity, a pair of identical twins. Every idiot can be father or mother to a genius—and vice versa. Every face and every set of fingerprints is effectively unique. Indeed, this uniqueness goes further in human beings than in any other animal. Whereas every deer or every sparrow is self-reliant and does everything every other deer or sparrow does, the same is not true of a man or a woman, and has not been for thousands of years. Every individual is a specialist of some sort, whether he or she is a welder, a housewife, a playwright, or a prostitute. In behavior, as in appearance, every human individual is unique.
How can this be? How can there be a universal, species-specific human nature when every human being is unique? The solution to this paradox lies in the process known as sex. For it is sex that mixes together the genes of two people and discards half of the mixture, thereby ensuring that no child is exactly like either of its parents. And it is also sex that causes all genes to be contributed eventually to the pool of the whole species by such mixing. Sex causes the differences between individuals but ensures that those differences never diverge far from a golden mean for the whole species.
A simple calculation will clarify the point. Every human being has two parents, four grandparents, eight great-grandparents, sixteen great-great-grandparents, and so on. A mere thirty generations back—in, roughly, A.D. 1066—you had more than a billion direct ancestors in the same generation (2 to the power of 30). Since there were fewer than a billion people alive at that time in the whole world, many of them were your ancestors two or three times over. If, like me, you are of British descent, the chances are that almost all of the few million Britons alive in 1066, including King Harold, William the Conqueror, a random serving wench, and the meanest vassal (but excluding all well-behaved monks and nuns), are your direct ancestors. This makes you a distant cousin many times over of every other Briton alive today except the children of recent immigrants. All Britons are descended from the same set of people a mere thirty generations ago. No wonder there is a certain uniformity about the human (and every other sexual) species. Sex imposes it by its perpetual insistence on the sharing of genes.
If you go back further still, the different human races soon merge. Little more than three thousand generations back, all of our ancestors lived in Africa, a few million simple hunter-gatherers, completely modern in physiology and psychology.6 As a result, the genetic differences between the average members of different races are actually tiny and are mostly confined to a few genes that affect skin color, physiognomy, or physique. Yet the differences between any two individuals, of the same race or of different races, can still be large. According to one estimate, only 7 percent of the genetic differences between two individuals can be attributed to the fact that they are of different race; 85 percent of the genetic differences are attributable to mere individual variation, and the rest is tribal or national. In the words of one pair of scientists: “What this means is that the average genetic difference between one Peruvian farmer and his neighbor, or one Swiss villager and his neighbor, is twelve times greater than the difference between the ‘average genotype’ of the Swiss population and the ‘average genotype’ of the Peruvian population.”7
It is no harder to explain than a game of cards. There are aces and kings and twos and threes in any deck of cards. A lucky player is dealt a high-scoring hand, but none of his cards is unique. Elsewhere in the room are others with the same kinds of cards in their hands. But even with just thirteen kinds of cards, every hand is different and some are spectacularly better than others. Sex is merely the dealer, generating unique hands from the same monotonous deck of genetic cards shared by the whole species.
But the uniqueness of the individual is only the first of the implications of sex for human nature. Another is that there are, in fact, two human natures: male and female. The basic asymmetry of gender leads inevitably to different natures for the two genders, natures that suit the particular role of each gender. For example, males usually compete for access to females, rather than vice versa. There are good evolutionary reasons for this, and there are clear evolutionary consequences, too; for instance, men are more aggressive than women.
A third implication of sex for human natures is that every other human being alive today is a potential source of genes for your children. And we are descended from only those people who sought the best genes, a habit we inherited from them. Therefore, if you spot somebody with good genes, it is your inherited habit to seek to buy some of those genes; or, put more prosaically, people are attracted to people of high reproductive and genetic potential—the healthy, the fit, and the powerful. The consequences of this fact, which goes under the name of sexual selection, are bizarre in the extreme, as will become clear in the rest of this book.
OURS TO REASON WHY?
To speak of the “purpose” of sex or of the function of a particular human behavior is shorthand. I do not imply some teleological goal-seeking or the existence of a great designer with an aim in mind. Still less will I be implying foresight or consciousness on the part of “sex” itself or of mankind. I merely refer to the astonishing power of adaptation, so well appreciated by Charles Darwin and so little understood by his modern critics. For I must confess at once that I am an “adaptationist,” which is a rude word for somebody who believes that animals and plants, their body parts and their behaviors, consist largely of designs to solve particular problems.8
Let me explain. The human eye is “designed” to form an image of the visual world on its retina; the human stomach is “designed” to digest food; it is perverse to deny such facts. The only question is how they came to be “designed” for their jobs. And the only answer that has stood the test of time and scrutiny is that there was no designer. Modern people are descended mainly from those people whose eyes and stomachs were better at those jobs than other people’s. Small, random improvements in the ability of stomachs to digest and of eyes to see were thus inherited, and small diminishments in ability were not inherited because the owners, equipped with poor digestion or poor vision, did not live so long or breed so well.
We human beings find the notion of engineering design quite easy to grasp and have little difficulty seeing the analogy with the design of an eye. But we seem to find it harder to grasp the idea of “designed” behavior, mainly because we assume that purposeful behavior is evidence of conscious choice. An example might help to clarify what I mean. There is a little wasp that injects its eggs into whitefly aphids, where they grow into new wasps by eating the whitefly from the inside out. Distressing but true. If one of these wasps, upon poking its tail into a whitefly, discovers that the aphid is already occupied by a young wasp, then she does something that seems remarkably intelligent: She withholds sperm from the egg she is about to lay and lays an unfertilized egg inside the wasp larva that is inside the whitefly. (It is a peculiarity of wasps and ants that unfertilized eggs develop into males, while all fertilized ones develop into females.) The “intelligent” thing that the mother wasp has done is to recognize that there is less to eat inside an already-occupied whitefly than in virgin territory. Her egg will therefore grow into a small, stunted wasp. And in her species, males are small, females large. So it was “clever” of her to “choose” to make her offspring male when she “knew” it was going to be small.
But of course this is nonsense. She was not “clever”; she did not “choose” and she “knew” not what she did. She was a minuscule wasp with a handful of brain cells and absolutely no possibility of conscious thought. She was an automaton, carrying out the simple instructions of her neural program: If whitefly occupied, withhold sperm. Her program had been designed by natural selection over millions of years: Wasps that inherited a tendency to withhold sperm when they found their prey already occupied had more successful offspring than those that did not. Yet in exactly the same way that natural selection had “designed” an eye, as if for the “purpose” of seeing, so natural selection had produced behavior that seemed designed to suit the wasp’s purposes.9
This “powerful illusion of deliberate design”10 is so fundamental a notion and yet so simple that it hardly seems necessary to repeat it. It has been much more fully explored and explained by Richard Dawkins in his wonderful book The Blind Watchmaker.11 Throughout this book I will assume that the greater the degree of complexity there is in a behavior pattern, genetic mechanism, or psychological attitude, the more it implies a design for a function. Just as the complexity of the eye forces us to admit that it is designed to see, so the complexity of sexual attraction implies that it is designed for genetic trade.
In other words, I believe that it is always worth asking the question why. Most of science is the dry business of discovering how the universe works, how the sun shines, or how plants grow. Most scientists live their lives steeped in how questions, not why questions. But consider for a moment the difference between the question “Why do men fall in love?” and the question “How do men fall in love?” The answer to the second will surely turn out to be merely a matter of plumbing. Men fall in love through the effects of hormones on brain cells and vice versa, or some such physiological effect. One day some scientist will know exactly how the brain of a young man becomes obsessed with the image of a particular young woman, molecule by molecule. But the why question is to me more interesting because the answer gets to the heart of how human nature came to be what it is.
Why has that man fallen in love with that woman? Because she’s pretty. Why does pretty matter? Because human beings are a mainly monogamous species and so males are choosy about their mates (as male chimpanzees are not); prettiness is an indication of youth and health, which are indications of fertility. Why does that man care about fertility in his mate? Because if he did not, his genes would be eclipsed by those of men who did. Why does he care about that? He does not, but his genes act as if they do. Those who choose infertile mates leave no descendants. Therefore, everybody is descended from men who preferred fertile women, and every person inherits from those ancestors the same preference. Why is that man a slave to his genes? He is not. He has free will. But you just said he’s in love because it is good for his genes. He’s free to ignore the dictates of his genes. Why do his genes want to get together with her genes anyway? Because that’s the only way they can get into the next generation; human beings have two sexes that must breed by mixing their genes. Why do human beings have two sexes? Because in mobile animals hermaphrodites are less good at doing two things at once than males and females are at each doing his or her own thing. Therefore, ancestral hermaphroditic animals were outcompeted by ancestral sexed animals. But why only two sexes? Because that was the only way to settle a long-running genetic dispute between sets of genes. What? I’ll explain later. But why does she need him? Why don’t her genes just go ahead and make babies without waiting for his input? That is the most fundamental why question of all, and the one with which the next chapter begins.
In physics, there is no great difference between a why question and a how question. How does the earth go around the sun? By gravitational attraction. Why does the earth go around the sun? Because of gravity. Evolution, however, causes biology to be a very different game because it includes contingent history. As anthropologist Lionel Tiger has put it, “We are perforce in some sense constrained, goaded, or at least affected by the accumulated impact of selective decisions made over thousands of generations.”12 Gravity is gravity however history deals its dice. A peacock is a showy peacock because at some point in history ancestral peahens stopped picking their mates according to mundane utilitarian criteria and instead began to follow a fashion for preferring elaborate display. Every living creature is a product of its past. When a neo-Darwinian asks, “Why?” he is really asking, “How did this come about?” He is a historian.
OF CONFLICT AND COOPERATION
One of the peculiar features of history is that time always erodes advantage. Every invention sooner or later leads to a counterinvention. Every success contains the seeds of its own overthrow. Every hegemony comes to an end. Evolutionary history is no different. Progress and success are always relative. When the land was unoccupied by animals, the first amphibian to emerge from the sea could get away with being slow, lumbering, and fishlike, for it had no enemies and no competitors. But if a fish were to take to the land today, it would be gobbled up by a passing fox as surely as a Mongol horde would be wiped out by machine guns. In history and in evolution, progress is always a futile, Sisyphean struggle to stay in the same relative place by getting ever better at things. Cars move through the congested streets of London no faster than horse-drawn carriages did a century ago. Computers have no effect on productivity because people learn to complicate and repeat tasks that have been made easier.13
This concept, that all progress is relative, has come to be known in biology by the name of the Red Queen, after a chess piece that Alice meets in Through the Looking-Glass, who perpetually runs without getting very far because the landscape moves with her. It is an increasingly influential idea in evolutionary theory, and one that will recur throughout the book. The faster you run, the more the world moves with you and the less you make progress. Life is a chess tournament in which if you win a game, you start the next game with the handicap of a missing pawn.
The Red Queen is not present at all evolutionary events. Take the example of a polar bear, which is equipped with a thick coat of white fur. The coat is thick because ancestral polar bears better survived to breed if they did not feel the cold. There was a relatively simple evolutionary progression: thicker and thicker fur, warmer and warmer bears. The cold did not get worse just because the bear’s insulation got thicker. But the polar bear’s fur is white for a different reason: camouflage. White bears can creep up on seals much more easily than brown bears can. Presumably, once upon a time, it was easy to creep up on Arctic seals because they feared no enemies on the ice, just as present-day Antarctic seals are entirely fearless on the ice. In those days, proto-polar bears had an easy time catching seals. But soon nervous, timid seals tended to live longer than trusting ones, so gradually seals grew more and more wary. Life grew harder for bears. They had to creep up on the seals stealthily, but the seals could easily see them coming—until one day (it may not have been so sudden, but the principle is the same) by chance mutation a bear had cubs that were white instead of brown. They thrived and multiplied because the seals did not see them coming. The seal’s evolutionary effort was for nothing; they were back where they started. The Red Queen was at work.
In the world of the Red Queen, any evolutionary progress will be relative as long as your foe is animate and depends heavily on you or suffers heavily if you thrive, like the seals and the bears. Thus the Red Queen will be especially hard at work among predators and their prey, parasites and their hosts, and males and females of the same species. Every creature on earth is in a Red Queen chess tournament with its parasites (or hosts), its predators (or prey), and, above all, with its mate.
Just as parasites depend on their hosts and yet make them suffer, and just as animals exploit their mates and yet need them, so the Red Queen never appears without another theme being sounded: the theme of intermingled cooperation and conflict. The relationship between a mother and her child is fairly straightforward: Both are seeking roughly the same goal—the welfare of themselves and each other. The relationship between a man and his wife’s lover or between a woman and her rival for a promotion is also fairly straightforward: Both want the worst for each other. One relationship is all about cooperation, the other all about conflict. But what is the relationship between a woman and her husband? It is cooperation in the sense that both want the best for the other. But why? In order to exploit each other. A man uses his wife to produce children for him. A woman uses her husband to make and help rear her children. Marriage teeters on the line between a cooperative venture and a form of mutual exploitation—ask any divorce lawyer. Successful marriages so submerge the costs under mutual benefits that the cooperation can predominate; unsuccessful ones do not.
This is one of the great recurring themes of human history, the balance between cooperation and conflict. It is the obsession of governments and families, of lovers and rivals. It is the key to economics. It is, as we shall see, one of the oldest themes in the history of life, for it is repeated right down to the level of the gene itself. And the principal cause of it is sex. Sex, like marriage, is a cooperative venture between two rival sets of genes. Your body is the scene of this uneasy coexistence.
TO CHOOSE
One of Charles Darwin’s more obscure ideas was that animals’ mates can act like horse breeders, consistently selecting certain types and so changing the race. This theory, known as sexual selection, was ignored for many years after Darwin’s death and has only recently come back into vogue. Its principal insight is that the goal of an animal is not just to survive but to breed. Indeed, where breeding and survival come into conflict, it is breeding that takes precedence; for example, salmon starve to death while breeding. And breeding, in sexual species, consists of finding an appropriate partner and persuading it to part with a package of genes. This goal is so central to life that it has influenced the design not only of the body but of the psyche. Simply put, anything that increases reproductive success will spread at the expense of anything that does not—even if it threatens survival.
Sexual selection produces the appearance of purposeful “design” as surely as natural selection does. Just as a stag is designed by sexual selection for battle with sexual rivals and a peacock is designed for seduction, so a man’s psychology is designed to do things that put his survival at risk but increase his chances of acquiring or retaining one or more high-quality mates. Testosterone itself, the very elixir of masculinity, increases susceptibility to infectious disease. The more competitive nature of men is a consequence of sexual selection. Men have evolved to live dangerously because success in competition or battle used to lead to more or better sexual conquests and more surviving children. Women who live dangerously merely put at risk those children they already have. Likewise, the intimate connection between female beauty and female reproductive potential (beautiful women are almost by definition young and healthy; compared with older women, they are therefore both more fertile and have a longer reproductive life ahead of them) is a consequence of sexual selection acting on both men’s psyches and women’s bodies. Each sex shapes the other. Women have hourglass-shaped bodies because men have preferred them that way. Men have an aggressive nature because women have preferred them that way (or have allowed aggressive men to defeat other men in contests over women—it amounts to the same thing). Indeed, this book will end with the astonishing theory that the human intellect itself is a product of sexual rather than natural selection, for most evolutionary anthropologists now believe that big brains contributed to reproductive success either by enabling men to outwit and outscheme other men (and women to outwit and outscheme other women) or because big brains were originally used to court and seduce members of the other sex.
Discovering and describing human nature and how it differs from the nature of other animals is as interesting a task as any that science has faced; it is on a par with the quest for the atom, the gene, and the origin of the universe. Yet science has consistently shied away from the task. The greatest “experts” our species has produced on the subject of human nature were people like Buddha and Shakespeare, not scientists or philosophers. The biologists stick to animals; those who try to cross the line (as Harvard’s Edward Wilson did in his book Sociobiology in 1975) are vilified with accusations of political motives.14 Meanwhile, human scientists proclaim that animals are irrelevant to the study of human beings and that there is no such thing as a universal human nature. The consequence is that science, so coldly successful at dissecting the Big Bang and DNA, has proved spectacularly inept at tackling what the philosopher David Hume called the greatest question of all: Why is human nature what it is?