Chapter One Born to Be Bad? There were dead people along the road, so my friends gave up trying to go to Fort Portal," Tedi explained. She had just walked eight miles through the primeval rain forest, a hike no Mutoro woman in her right mind would make due to its dangers. But her husband, Otim, was my game ranger, and she had come to warn us. The dead people, Acholi and Langi--both East Nile tribes--were victims of Idi Amin Dada's latest (February 1977) genocidal pogrom. A Kakwa from the West Nile, Amin was determined to erase from Uganda all Langi and Acholi people, hereditary enemies from the east. President Milton Obote, whom Amin had deposed six years earlier, was a Langi. And Obote's tribesmen, all conveniently bearing surnames beginning with the letter O , could never be anything but enemies. For Amin, the only good enemy was a dead enemy. Our problem was that Otim was a Langi. Only a dozen miles away from our tiny encampment at Ngogo, in the center of Kibale Forest, blood was flowing. Amin had ordered his army of West Nile rogues, illiterates, and sadists to eliminate all Langi and Acholi occupying all official positions, from postal clerks and schoolteachers to district commissioners. His gangs of armed thugs were breaking into schoolrooms, offices, businesses, private homes, and even bush huts to drag off innocent Langi people. Once these people were outside, the thugs hacked off their heads with pangas (machetes). Thousands of Acholi were simply machine-gunned en masse. A dozen miles from our enclave in the jungle, entire rooms full of living Acholi and Langi prisoners were wrapped together with wire, doused with kerosene, and set ablaze. That same night, Amin's censored Voice of Uganda radio network broadcast allegations that an invasion force from Tanzania (where Obote still lived in exile) had violated Uganda's borders and was being assisted by Langi and Acholi rebels under Obote's leadership. By definition, all Langi and Acholi were state enemies. Amin's dreaded gestapo, the State Research Bureau (SRB), was now carrying out mass executions of them. Outside this jungle that concealed us, Otim would die. I worked out a plan for Otim's escape into the forest should we hear Land Rovers approaching. Engine noise two miles away would be audible, giving us plenty of time to make him vanish. With only a little luck, I reckoned, Otim would live through this pogrom. And when Amin cooled off again, Otim could seek sanctuary in Tanzania or Kenya. Meanwhile, the Voice of Uganda reported a new twist in the alleged Tanzanian invasion. The rebel force was being assisted by American mercenaries. All Americans in the country (there were forty-six of us, mostly missionaries and pilots) were ordered by Life President Idi Amin Dada to assemble immediately at Entebbe International Airport for expulsion--after signing over all our personal property to the government of Uganda. Being only three months into my research on wild chimpanzees but already having made major breakthroughs, I was now about to lose out again to African politics. I perused my maps. The nearest escape route would skirt the southern fringe of the Mountains of the Moon into Zaire. To avoid becoming one of Amin's three thousand murder victims this week, I would have to avoid all roads and villages, travel at night, and bivouac in thick foliage. But I had not seen much of this terrain yet, and the trip would take several days even if everything went well. Either way, I would carry all of my data sheets. Should Otim come along? Or should we both sit tight a bit longer? One thing we had going for us was that Ngogo was incorrectly located by several miles on government topo maps. Even so, there were villagers out there who knew where we were. And some of them were poachers whom we had chased out of the nature reserve -- men with grudges. I decided to stay put a bit longer. Maybe we'd survive Amin's genocide against rival tribes (including Americans) long enough for me to gain some insights from the wild chimpanzees on the origins of such barbaric genocidal behavior. * * * Differences Between Girls and Boys My wife, Connie, and I have a daughter and a son eighteen months apart. By age three, our daughter, Crystal, spent hours building beds for her dolls, stuffed animals, ponies, and even her dinosaurs and a Halloween bat. She tucked them lovingly into their blankets and propped their heads on pillows. She put bandages on their imaginary wounds. She talked and sang to them and brushed their manes. She arranged them all in a cozy circle around a tablecloth and fed them with a spoon at polite, orderly picnics. She nurtured her menagerie as if she had studied child psychology. And she scolded them if they acted naughty. She also demanded of her mother and me--on pain of a tantrum--that she wear dresses, even in two feet of snow. She had to look feminine. Today, eight years later, Crystal no longer insists on dresses, but she is fixated on horses and is even more nurturing and security-conscious. At three years old, her brother, Cliff, shot the same stuffed animals with toy guns, stabbed them with a rubber knife, hacked them with his plastic sword, and toppled them off the staircase in death plunges. His dinosaurs did nothing but attack and kill each other and gorge themselves on the bloody carcasses. Cliff never spoon-fed, hugged, bandaged, consoled, instructed, or scolded anything. His clothes simply had to be comfortable. Today he's a Boy Scout, wants to be a river guide and a U.S. Air Force pilot, and plays computer and video games like an addict. The goal of these games? To kill the bad guys. As the years pass, the gender gap continues to widen. So a brother and sister are different, you might say. Big deal. Two kids prove nothing. Two friends of ours, one a social psychologist and the other a psychoanalyst/social anthropologist, have a girl and a boy of similar ages. To avoid programming their four-year-old son with violent tendencies, the mother allowed him no toy weapons. Much to her dismay, he relentlessly prowled the woods around their house in search of sticks shaped like guns, which he used to shoot things. Her daughter never did this. Instead, she acted like a girl. This tormented the mother. But this also proves nothing. Scientific or not, most of us know that men and women, or boys and girls, are different. Parents know it. Teachers know it. Husbands usually suspect it about their wives. Wives are certain about their husbands. It is no secret, despite the politically correct insistence that men and women are equal in every sense. Of course, women and men are equal in their value as people and in their legal rights. But otherwise men and women really are different--so different, so early, that infant boys and girls behave as if they were programmed for widely divergent roles. As if men were born to be bad. We do know that children everywhere identify as masculine or feminine before they are two years old and that they insist on copying their own gender. Not even surgical sex changes on male babies eighteen months old can reverse the pattern to female. Children fine-tune their behavior by watching older people. By age two, girls copy or imitate their mothers (or, if they lack a mother to copy, they imitate other mothers), boys imitate their fathers. Significantly, this division seems to prime boys for violence. It happens everywhere. All this is clear from an astoundingly detailed global study by German ethologist Irenäus Eibl-Eibesfeldt. It reveals that older boys worldwide mostly play contest games of pursuit and scuffling, do experiments, and commonly practice fighting--despite their being punished far more often than girls for being aggressive. Girls, meanwhile, play more sedate and even solitary games that often focus on security. Even more intriguing, children are likely to imitate behaviors that they see as appropriate to their own sex regardless of the sex of the actor. American experiments in child development, for example, reveal that a girl will copy "feminine" behavior seen in a man before she will imitate aggressive or bullying "masculine" behavior seen in a woman. The human urge to adopt an "appropriate" gender is so powerful that it succeeds even without gender roles to copy. The Israeli kibbutz experiment provides an inadvertent test of this. This Israeli system tried to create monogenderal roles by rearing children communally. But most of the children, who had no family role models to copy, invented their own families. The kibbutz also failed to eradicate stereotypical roles, even during play. Girls grew up focusing not only on female role models but also on maternal role models. The fact that gender among kibbutz children emerged as the most powerful and unchangeable root of their identity, despite communal rearing, hints at the depth of the human instinct to lock into the "right" gender. Yes, parents do reinforce this natural process, often unconsciously, and they usually do so from the moment their children are born. Mothers and fathers, however, nurture their sons and daughters differently. Mothers, for example, soothe and comfort their infant girls more than their infant boys, but they burp, rock, arouse, stimulate, stress, look at, talk to, and even smile at their infant boys more. Mothers also hold their infant boys closer. Still, it is children's self-directed sex differences so early in life that spotlight the most fundamental question of human behavior and men's violence: Are the psyches of men and women intrinsically different in design? And if so, how and why? Are men somehow born to be bad? Or do they start out innocent and then get corrupted? The Evolution of Sex Differences Admittedly, these questions about the basic designs of the human male and female psyches are politically radioactive, but the answers to them are matters of life and death. Finding these answers demands that we sweep the table clean of several widely held but now untenable ideas about human behavior. As the nineteenth-century humorist Artemus Ward observed, "It ain't so much the things we don't know that get us in trouble. It's the things we know that ain't so." That Homo sapiens is still locked in an identity crisis is ironic. How hard could it be for us to figure ourselves out as a species? Why can't we simply stand in front of the mirror of science, so to speak, and look at ourselves with an objective eye? The answer is that the old nature versus nurture debate fogs the mirror. For example, the claim by Franz Boas, Friedrich Engels, John Locke, Karl Marx, Margaret Mead, and B. F. Skinner that humans are born as malleable blank slates that become pure products of cultural indoctrination has consistently sabotaged the exploration of human nature by denying that we have a psyche equipped with instincts. It is society, the modern-day protégés of these philosophers and social scientists still insist, that creates the mental software that rules people's behavior. Meanwhile, the rival claim by many biologists that we humans carry a legacy of instincts from our primeval past--a human nature--disturbs some of us so much that the heat we feel during such discussions stops us from seeing the light. To break the cycle of dogma here, biologists insist, we first must admit that humans are a biological phenomenon. Like all other mammals, we must eat, breathe oxygen, excrete, and seek warmth--in short, survive. If our DNA is to make it to the next generation, we must also mate and rear our offspring successfully. Just how biological are we? For the answer, ask any medical doctor how she was trained. She will tell you that she was inundated with every known aspect of human biology. Boring though this may seem to many of us, it is a good idea. If medical doctors instead focused mostly on sociology and political theory for their medical training, we would likely feel far more nervous than we already do when that ice-cold stethoscope stings our chest. OK, so we're biological. But is human behavior truly influenced in a substantial way by our biology--by our genes? We know that behavior in other animals is. Robert Plomin found that many behaviors can be enhanced, created, or eliminated through selective breeding. More to the point, Plomin discovered that inheritance plays a role in human behavior. For example, at least one hundred different gene effects, most of them very rare, are now known to lower IQ. The specific genes that influence behavior are numerous "needles in the haystack" of the DNA molecule. "Just 15 years ago," Plomin concludes, "the idea of genetic influence on complex human behavior was anathema to many behavioral scientists. Now, however, the role of inheritance in behavior has become widely accepted, even for sensitive domains such as IQ." Another study found that the IQs of 245 adopted children more closely matched those of their biological parents than those of their adoptive parents, who created the children's environment. Among identical twins from the Minnesota Study of Twins Reared Apart, 50 to 70 percent of variance in IQ was associated with genetics. Even more amazing, note Thomas J. Bouchard, Jr., and his colleagues, authors of the study, "on multiple measures of personality and temperament, occupational and leisure time interests, and social attitudes, monozygotic twins reared apart are about as similar as monozygotic twins reared together!" Human behaviors now known or suspected to be based on genetics include amount of alcohol consumed, autism, language disability, panic disorder, eating disorders, antisocial personality disorder, and Tourette's syndrome. Even the tendency to divorce a spouse seems significantly influenced (52 percent heritability) by one's genes. Recent research by psychologist Jim Stevenson suggests that personality traits, especially "nice" traits, are genetically linked. Working with twins, Stevenson found that more than half of the variance associated with "prosocial" behavior was linked to genes. Only about 20 percent of "antisocial" behavior was. In short, much of our behavior is substantially influenced by our genes, but much also is influenced by our environment. "Any analysis of the causes of human nature that tends to ignore either the genes or environmental factors," concludes physical anthropologist Melvin Konner, "may safely be discarded." The basic premise of this book is that we are understandable both from a biological perspective and in an environmental context. Nature equipped each of us with a complex brain ruled by chemical neurotransmitters that spur in us instinctive emotional responses to situations, which in turn influence our behavior. This may not be a comfortable way to look at ourselves, but biology tells us that this is the only accurate way and, more to the point, that it is the only way that offers us any real hope of understanding our behavior, including our use of violence. The counterargument that humans are impossible to understand because our culture shapes our behavior far more than biology does is often little more than a monkey wrench tossed into the discussion to grind it to a halt before it treads on politically incorrect turf. To deflect this monkey wrench and to test ideas about human violence, this book will look not just at human beings but also at our nearest living relatives, the great apes, none of which have been immersed in human culture. Indeed, a close look at orangutans, gorillas, or chimpanzees is as startling as walking in `front of a mirror, knowing the reflection is of ourselves but seeing someone else's face. The great apes offer us more than just an eerie glimpse of the basic behavioral software from which humanity emerged. They also provide us with insights into the origins of human violence--insights that help make it possible to understand the human male psyche. This glimpse of our evolutionary past did not come easily. It took more than thirty-five years of field research by hundreds of scientists to reveal how and why the great apes socialize with each other. We now know that each individual ape socializes--cooperatively or aggressively--based on its own decision on how to enter the reproductive arena, an arena that demands being social in some way . The lives these apes lead are shaped by instinctive social "rules" that are violent, sexist, and xenophobic. Understanding how these rules work offers us the only informed approach to understanding the roots of human violence. The upcoming chapters on rape, murder, and war each offer a short natural history tour of similar violence by great apes. First, however, we must look at the evolutionary process that made the priorities of males and females so utterly different and made men so violent. If not for the insights of a medical school drop-out who became a naturalist on a five-year voyage around the world, we still might not have a clue as to why the sexes differ. The reasons are revealed first in Charles Darwin's 1859 blockbuster, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, a book that sold out the same day it hit the book shops, and for good reason. In it Darwin redefined the "Hand of God." Although Darwin is now a household name, many of us are hazy on what he actually said. So here is Darwin's concise definition of evolution's prime architect: As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected.... This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection. Evolution, we now know, works by natural selection "editing" new alleles (alternate forms of a gene that arise through mutation) via each allele's effects on reproductive success. Indeed, the modern, neo-Darwinian definition of evolution is simply a change in the frequency of alleles in a population from one generation to the next . Field research on hundreds of species of wild plants and animals has documented natural selection in action. Jonathan Weiner's The Beak of the Finch offers a fascinating view of this process as seen during long-term work on Darwin's finches in the Galápagos Islands. Neo-Darwinian theory is so well established that, regardless of the biochemistry of heredity, we know that natural selection must be happening on every planet in the universe on which life exists. How important is this? "For a biologist," notes Nobel Prize-winning immunologist Sir Peter Medawar, "the alternative to thinking in evolutionary terms is not to think at all." A dozen years after redefining the "Hand of God," Darwin boosted our understanding of why males and females are so different--and why males are so violent--by explaining a special form of natural selection he called sexual selection . This process enhances traits within one sex that help its members win against sexual rivals. It works in both sexes, and it works in two ways. Among males, one way is the "pretty male strategy." Males winning via this strategy sire more offspring because females choose these males more often as mates based on traits the females prefer. The second way sexual selection works is the "macho male strategy," in which some males breed more than others because they defeat rival males and exclude them from breeding. (Females, depending on their species, also can compete via either of these strategies. But females also use a third strategy, called the "supermom strategy," in which they compete based on the efficiency of their reproductive equipment.) It is macho male sexual selection that leads to war, rape, and most murder in nature. The explanation of how this process occurs was refined by biologist Robert L. Trivers, who defined the concept of parental investment as "any investment by the parent in an individual offspring that increases the offspring's chance of survival (and hence reproductive success) at the cost of the parent's ability to invest in other offspring." Among all mammals, for example, reproduction is limited by the physiology of females, who have no choice but to invest more than males in offspring by nursing them during their months or years of infancy. How does this lead to violence? Among human hunter-gatherers, mothers must invest four to five years exclusively in each child. These women cannot hope to raise more than three or four children who survive to adulthood. But during this approximately twenty-year period, men, whose bodies are not required as an exclusive nurturing machine bonded for years to one infant, can sire a hundred offspring, or a thousand. Physiologically, a man can fertilize a different woman every day or two. And some men try to. As long as some of these men's "extra" children survive, sexual selection will favor male genes that increase their chances of convincing "extra" women to mate with them. Indeed, it seems that all male mammals are governed by the same rule: he who mates the most wins. The problem every male faces in mating with yet more females, however, is that males and females normally exist in nearly equal numbers, and there are few "extra" females. Enter violence. The sex that must donate more parental investment per offspring becomes the limiting factor for the genetic fitness of the other sex, which, since it donates less investment, is free to wander. This leads to huge differences in the reproductive strategies of the sexes. As we see in many nature videos, male mammals use their "free time" to compete violently for very limited opportunities to mate again and again. In nonmammalian species, the sex that competes for extra mates most violently may be the female sex. Among cassowaries in Australia's tropical rain forests, for example, females are the aggressive (macho) sex. To defend or expand their territories and to evict all female competitors, these six-foot-tall birds, armed with a three-inch claw/spike that can disembowel a dingo, battle each other using brutal kicks. A victorious female then mates with as many males as she can find, one after the other. She leaves each with a clutch of her eggs. The males, who are one-third smaller than the females, dutifully incubate the eggs, driving off predators and sometimes going up to fifty days without food to protect the clutch. When the eggs hatch, the male leads his brood of tiny hatchlings around the rain forest and demonstrates survival skills. The lesson? Sexual selection is an equal opportunity process, but it cannot work unless fueled by disparities in parental investment. Among mammals, females always bear a heavier burden in terms of parental investment. And the bigger the gap between what female mammals must invest and what males must invest, the more intensely the males compete. If we knew only this about mammals, we would expect males to be violent toward one another. Though far from being politically correct, sexual selection favors the genes of males who sire more offspring no matter how they have done it . Via the "pretty male strategy," sexual selection reinforces males' allure to females--as epitomized by the most brilliant plumage on male birds of paradise or the longest, most extravagant tails on male widow birds, both of which lead to the highest reproductive success for males. Via the "macho male strategy," sexual selection reinforces greater size, strength, speed, weapons, prowess in combat, intelligence, sneakiness, strategic sense, and even proclivity to cooperate with male kin in coordinated combat. "All's fair in love and war" was penned by sexual selection, whose core logic commands individuals to "beget more children no matter how." Sexual selection reinforces an endless arms race of sexual dimorphism , in which males end up "this way" and females end up "that way." What does this have to do with men? Unlike gorgeous male birds, most male primates are drab. In surveying three hundred published reports of mating behavior among higher primates, physical anthropologist Meredith F. Small found no example of females preferring specific types of males. Instead, females simply mate with those males who are victorious in dominance fights with other males--mainly because these are the only males remaining on their feet in the mating arena. In short, the "pretty male strategy" is close to meaningless to polygynous male primates, who instead use the "macho male strategy" to the hilt. It also seems meaningless to females, because their only option is the male who possesses the guts, savvy, and strength to be physically present. Among male primates, not only does "might make right," but superiority in combat is the only sure road to reproductive success. How closely nature follows the "might makes right" axiom has even been quantified. For example, a team led by Tim Clutton-Brock, Fionna Guiness, and Steven Albon spent twelve years measuring the lifetime reproductive success of red deer on Scotland's Isle of Rhum. Stags are twice as big as hinds and brandish their huge antlers not as ornaments but as weapons. Without larger than average body size and larger antler size, a stag cannot forcibly exclude other stags and thus mate with multiple hinds. Combat is so intense that it prunes the reproductive life span of stags to a breeding prime only half as long as a hind's. Young and old stags are excluded from breeding by stags in their prime. Indeed, losing in combat eliminates some stags from breeding throughout their lives, while winning makes others into macho studs. The lifetime range for stags was zero calves sired by losers in combat but up to thirty calves sired by winners. Meanwhile, no hind bore more than twelve calves. The lesson here is that the single most useless--and dangerous--approach one could take in trying to explain human violence is to look only at nurture, while ignoring how sexual selection has sculpted the evolutionary software programming the differences between men and women. What differences? The Sexual Blueprints "Next to being human, your most obvious characteristic is being male or female," notes psychologist Herant Katchadourian. "Virtually every society expects men and women to behave differently both in occupational and relational settings--particularly in sexual interactions." This is sensitive territory. Even to mention sex differences these days is to stumble into a political minefield, because putative differences have been widely misused to justify unfair double standards in gender roles, sexual habits, opportunities, worth, and freedom. Since the 1960s, many social scientists have, in an effort to preserve their ideology, redefined gender (sex roles) to mean behaviors resulting from socialization and redefined sex as a physical trait due to chromosomes. Although it is true that sex is biological and that gender consists mostly of behaviors that children learn, gender emerges from both sex-specific instinct and socialization. The violence that "genderization" fosters is an instinctive strategy that men learn they can get away with when other strategies fail. Everything we do--eating, defecating, mating, parenting, and defending ourselves (ail of which are entirely biological in origin)--is shaped by both biology and social learning. The biology of behavior is always mitigated to some degree by nurture. It is this degree, on a case-by-case basis, that makes our quest to understand men's violence so fascinating. To get a better view of why men differ from women, let's do an experiment. Try to imagine men and women being identical in all respects: behavior, psychology, sexual orientation, size, physiology, athletic ability--everything except their genitals. Are you visualizing this? Does it compute? Probably not. This is because the sexes are so different that most of us cannot even imagine them being identical. Sex, above all other traits, is The Cornerstone of human behavior. But sex is defined biologically by the types of gametes, or sex cells, an individual produces. Females produce large eggs containing DNA plus nutrients for the developing embryo. Males produce tiny motile sperm containing little more than DNA. The mission of these tiny swimmers is to search, find, and fertilize. Beyond these gametes, sexuality itself is merely a reproductive strategy that allows two individuals to mix their genes and thus maximize the odds that some of their offspring will be born better adapted to flourish--or at least better able to outfox parasites--in a changing world. But this strategy of being sexual carries a price tag for both sexes: first, in the additional cost of the mating effort required to compete for, attract, and support a quality mate, and second, in the parental investment each sex must make to raise offspring. The differences in reproductive effort faced by men and not women--and vice versa--are precisely what molded both human nature and gender and what fueled sexual selection to design men and women to be born destined to diverge in their behaviors . "Females and males," explains Meredith F. Small, "are apples and oranges thrown into the same basket." Ironically, both sexes start out almost identical. The basic blueprint of all mammals is a female one, and it stays female unless it is changed by masculine hormones. Hormones are encoded by genes. Each person's genetic makeup consists of twenty-three pairs of chromosomes, twenty-two of which contain DNA possessed by both sexes. The last pair are the sex chromosomes, X and Y. Females have two X chromosomes; males have one X and one Y. Among our hundred thousand genes arrayed on these forty-six chromosomes, the message "become male" is written by just one. This "master sex switch," which instructs XY people to become males, is a chain of 140,000 nucleotide bases called interval 1A2 . Interval 1A2 is a mere five-hundredths of the Y chromosome--only 0.2 percent--but it holds the master gene, testis-determining factor . Identified in 1994, this critical gene encodes for SRY, a DNA-binding protein. The acid test of interval 1A2 and gene SRY was done by nature. People with an X and a Y chromosome lacking interval 1A2 are sex reversed; they are women. In contrast, XX people, whom we'd expect to be women but who possess the anomaly of interval 1A2 attached accidentally to one of their X chromosomes, are men. In normal XY human embryos, interval 1A2 and gene SRY trigger the testes to develop at nine weeks and then a penis and scrotum at twelve weeks. The testes then secrete Müllerian-inhibiting hormone, causing the rudimentary female ducts to degenerate. The testes also secrete testosterone. By contrast, normal XX embryos develop ovaries by the tenth week. These secrete the female hormones, estrogen and progesterone. Four weeks later, the clitoris and labia develop. Interestingly, both sexes secrete nearly the same hormones but in different proportions. These two hormonal "recipes" induce either maleness or femaleness. These recipes are so critical that two or three days after a male is born, his testosterone levels spike and stimulate the brain and hypothalamus to produce a male pituitary gland that secretes male gonadotrophic hormones. Injecting female hormones into any male mammal at birth will make its brain permanently nonmale. Such males will, among other things, fail to recognize females as mating partners. The human brain is, by default, female until male sex hormones change it. Psychiatrist Richard Pillard suspects that Müllerian-inhibiting hormone helps defeminize the brain. So does testosterone. Abnormally high levels of testosterone in infant girls (due to a single enzyme disorder precluding cortisol production) cause them to become aggressive tomboys who rarely want to settle down by marrying one man. Some of the women experienced a malelike libido so intense that, upon finally receiving cortisone treatments to reverse it, they admitted liking the loss of their constant edge of sexual urgency and finally feeling like "normal" women. In contrast, low levels of testosterone in utero predispose men to homosexuality. There is no question that human embryos sit on the gender fence until hormones topple them to one side or the other. Research shows that male sexual orientation is genetic, not environmental. A gene has even been found--among the several hundred genes in interval Xq28 (on the X chromosome)--that permanently switches men's sexual orientation from women to men. Testosterone is so powerful that it has become a cliché used to explain male idiocy. Yet testosterone's reputation for making males act like males is well deserved. Testosterone reduces fear, increases aggression, and speeds the glucose supply to muscles. At adolescence, male levels of testosterone increase twenty- to thirtyfold and spur a growth spurt in the young male's trunk, shoulders, heart muscles, lungs, eyes, facial bones, and overall height. Even the number of red blood cells suddenly increases. Men average seventy-seven pounds of muscle mass, compared to fifty-one pounds in women. This disparity is even greater than it seems: male muscles are 30 to 40 percent stronger biochemically, pound for pound, than women's and are quicker to neutralize chemical wastes such as lactic acid. In women, meanwhile, estrogen from the ovaries stimulates widening of the hips and causes the onset of menarche and the maturation of the uterus. Genes on the X chromosome actually limit women's muscle mass so that women need only two-thirds the calories that men do in basal metabolism. When these growth spurts end, men are so much stronger in athletics that even in our politically correct society, the sexes do not compete as equals except in horseback riding and shooting. The biochemical evidence is unrelenting: men are designed by nature for higher performance in aggressive, physically demanding action. But testosterone does even more. Primatologist Robert M. Sapolsky found that aggression by a male is what most perpetuates more aggression in that same male--and that testosterone is the key player. Clashes between baboons in Kenya's Masai Mara, for example, are chronic and stressful. Testosterone levels in most males plunge immediately when they are stressed. In dominant males, however, testosterone levels rise during the first hour of stress. Sapolsky found that dominant males have the ability to inhibit the production of cortisol (the human stress hormone that demasculinized those women with male libidos discussed earlier) and thus keep high levels of testosterone. This ability lies in each male's personality. Males who keep their cool--and their testosterone--when challenged by rivals do three things: they recognize whether a rival is neutral or threatening; they attack all who threaten; and, even if they lose a fight, they grab an innocent scapegoat and punish him or her soundly. The top males fight aggression with aggression and fire with fire in a self-feeding cycle that keeps them jacked up on testosterone and hyperaggressive. "Attitude counts," Sapolsky concludes, so much so that perception of external events "can alter physiology at least as profoundly as the external events themselves." That attitude can determine reality is an important lesson. But the more important lesson here is that male primates are designed--and primed by testosterone--to create their own reality through an aggressive attitude . In humans, this becomes obvious early. Three- to five-year-old boys are far more aggressive (fighting and threatening) than girls. They also share food altruistically less often than do girls. By age nine, boys create peer hierarchies in which the most aggressive boys predictably get what they want first. Girls are also aggressive, but in a very different way: they generally use prosocial aggression to enforce rules. Common among girls is the threat, "If you don't stop doing that, I'll tell." Far rarer are fistfights and raw physical intimidation. The divergent behaviors of girls versus boys and women versus men pose another question: Are the brains of men and women different? And if so, do men have "more violent" brains? Differences Between Women and Men The human brain, male or female, is nature's magnum opus. It contains 100 billion neurons, each interconnected by up to 100,000 dendrites. The brain is structurally and functionally organized into discrete units, or modules, that create our mental states and cognitive thoughts. The brain is also a use-it-or-lose-it organ. The act of learning is one of the major events that stimulates the brain's dendritic connections and terminal branches to multiply. Not using one's brain is as devastating to mental potential as not using one's body is to athletic potential. Are the brains of men and women truly different? Intelligence tests offer clues. Before 1972, women performed better on tests of verbal skills. Since then, men have consistently outscored women in mathematical calculating, conceptual ability, spatial orientation (especially in mapping their own environments, even at six years old), and the ability to separate a figure from its background. "Much independent evidence suggests that male hormones [androgens], both in utero and at puberty, elevate spatial ability," conclude Steven Gaulin and Harold Hoffman. These authors hint that men's spatial ability stems from the need to defend their territory. At least to some extent, hormones are again the culprits. Changes in women's cognitive performance, for example, follow their cyclical levels of estrogen and progesterone. Women tested in the 1980s performed fine motor tasks best when their sex hormone levels were high and did significantly better in spatial reasoning tasks when those levels were low. Also intriguing is evidence that women commit significantly more crimes just before their menstrual periods. These differences emerge not just in psychological testing but in professional life. The top ten American mathematics departments were staffed in the 1990s by 303 tenured men and four tenured women. Further, on Scholastic Aptitude Tests (SATs), nearly all the most mathematically gifted students are boys. Oddly, boys scoring above 700 (the 99th percentile) were found to have five times more immune system disorders, such as asthma, than normal boys. This suggests, too, that hormonal biochemistry may supercharge or limit certain brain functions. In contrast, no evidence so far confirms the argument that reinforcement of sex roles at home, in school, in sports, or at work enhances men's abilities to perceive space and to solve insight problems more than women's. Instead, it is clear that the brains of men and women do differ--just as male and female brains in all mammals differ. In humans, they differ specifically in the numbers and sizes of neurons; in dendritic spines and length of branching; in synaptic numbers, types, and organization; in regional nuclear volume; in volume of neural structures (thalamus, anterior hypothalamus, and corpus callosum); and in the locations of verbal processing. Although these differences are real, none of them tells us why men are more violent than women. What they do tell us is that the organ that initiates behavior is visibly different in men and women. Brain research aside, the commonly perceived differences--physical, mental, and emotional--between men and women have fueled a double standard. In 1912, for example, the Titanic sank with lifeboats for less than half her 2,208 passengers and crew. The rule was "women and children first." The mere 705 survivors included at least 90 percent of all women on board. Some men in first class also escaped, but 92 percent of the men in second class drowned. Whether this reveals that men in power value women over other men, or worse, that men in power take any opportunity to eliminate other men--or whether it reveals that both are true--remains an open question. But in reality, men died and women lived due to the sexual double standard in which women are viewed as prime property more valuable than men. The opposite side of the double standard is the sexist devaluation of women. As recently as 1990, for example, American women earned salaries only 72 percent as much as those paid to men with equal training. Why? Industrial giant J. Paul Getty offers one perspective in his book As I See It . During World War II, Getty supervised the 5,500 employees of his Spartan Aircraft Corporation, one-third of whom were women. He writes: One of the more surprising discoveries I made was that women were completely honest and straightforward about their capacities and limitations. Asked to perform some task beyond their ability and experience, they would openly admit they could not do it and ask to be taught or shown. Not so the men. They could not bring themselves to confess ignorance or ineptitude. Instead they would usually claim full understanding and try to bluff their way through-- making very costly mistakes and blunders in the process. Roles reversed when it came to taking criticism. Male workers accepted criticism of their work matter-of-factly, taking no personal offense. Women almost invariably reacted to any critical remark about their work as though it was an all-out attack on them as individuals. Their eyes would fill with tears or they would burst out crying or flee into the women's restroom. Afterwards, they were likely to sulk for hours--or days--or even quit entirely. Although Getty never says whether he considered men or women to be better employees, he leaves no doubt that he saw them as different kinds of employees. Unfortunately, many men do insist that women are inferior, and they often refuse to value them as equals on the job. In The Descent of Woman , feminist Elaine Morgan concedes a key difference between men and women that moves us closer to understanding violence: "When all the factors of prejudice and self-interest have been discounted, the fact remains that on average women put less of themselves into their work than men do, simply because they are childbearers and wives as well as workers." Here Morgan focuses on a fundamental chasm between men's and women's priorities and psychologies that goes well beyond the workplace and into basic reproductive biology. Indeed, this chasm reflects one of the deepest but most poorly recognized roots of men's violence. To see how and why this is so, we must first ask a key question concerning human sexual behavior: what do most women and men really want from each other? I Love You Because ... While answers to the question of what men and women want from each other could fill this book--and indeed have filled many books aimed at helping befuddled men (which includes all men at one time or another)--women have already stated what they want. And in just a handful of words. "Whatever women say in public about their willingness to share the burden of making a living, in private I hear something entirely different," says veteran marriage counselor and clinical psychologist Willard F. Harley, Jr., who, by 1986, had spent twenty years interviewing fifteen thousand troubled couples. "Married women tell me they resent working, if their working is an absolute necessity.... A husband's failure to provide sufficient income for housing, clothing, food, transportation, and the other basics of life commonly causes marital strain in our society," Harley adds. "No matter how successful a career woman might be, she usually wants her husband to earn enough money to allow her to feel supported and to feel cared for." Harley suggests that although women may want several things from their husbands, most women place a very high priority on material security. Anthropology agrees with him. Biological anthropologist Laura Betzig, for example, found that more women worldwide prefer to marry an economically successful man who already has a wife rather than a man who is single but poor (most human societies are polygynous). Betzig also found that wealthier men worldwide marry more wives and have many more lovers than poorer men. Anthropologists Kim Hill and Hillard Kaplan likewise found that Ache women of the Paraguayan rain forest are most attracted to the best hunters. This is true even if the women can manage only an adulterous relationship with these men. Ache hunters supply 87 percent of all calories consumed. Hunters with shotguns are the most successful. Not only do they raise their catch from 910 calories to 2,360 calories per hour of hunting; women seek them most often as mates or lovers. In contrast, mediocre Ache hunters rarely can find a woman willing to marry them. For Ache men, shotguns are the equivalent of a six-figure salary among North American men; both groups have access to sex with more partners than do their less wealthy peers. What about men and women globally? For six years, psychologist David M. Buss and fifty colleagues explored preferences among ten thousand people in thirty-seven countries from Africa to North America. Both sexes, Buss found, prefer a partner who is loving, stable, dependable, and pleasant. But these traits do not tell us much. They alone do not satisfy most people's criteria for a mate except perhaps a man who wants a "Stepford wife." For example, the most common trait people wrote in (Buss did not list it on his original questionnaire) was "a sense of humor." On top of these qualities, Buss found that men are universally attracted to young, attractive, and "spunky" women. (Revealingly, America's $8-billion-per-year porn business also demands young women in their late teens or early twenties, yet this industry uses actors well into their forties.) "In each of the 37 cultures," Buss reports, "men valued physical attractiveness and good looks in a mate more than did their female counterparts. These sex differences were not limited to cultures that are saturated with visual media, Westernized cultures or racial, ethnic, religious, or political groups. Worldwide, men place a premium on physical appearance." In contrast, although many women in Buss's study said that they were attracted to physically strong men, "in 36 out of the 37 cultures, women placed significantly greater value on financial prospects than did men.... Women desire social status and ambition-industriousness in a long-term mate more than their male counterparts do." Lonely hearts ads by American women reveal that they too most often seek mates with resources and status. These ads also reveal that heterosexual women are three times more likely to seek socioeconomic resources in a mate than are lesbians. Even more revealing, Willard F. Harley, Jr., found that among the women he interviewed, attractive women often said that they found ugly but economically successful men who treated them well physically attractive. To these women the men's blemishes vanished. Sexual "attractiveness" is so sex specific and, for women, so intermeshed with "promises" of ability to provide resources, that even researchers are surprised. Psychologist John Marshall Townsend studied the mate preferences of 1,180 American men and women from varying backgrounds. He presented people with an array of photos of models dressed either in high-status garb or in Burger King uniforms. The women in this study found an ugly man wearing a blazer and a Rolex watch equally acceptable as a dating partner as a handsome man wearing a Burger King uniform. These women's bias toward wealthy men increased even more when they were asked to consider the ugly man as a potential husband or father of their future children. Townsend concluded that women who say that they focus on "love" and "commitment" in a man are actually more concerned with the man's ability to invest in them financially. When a woman says "I have to respect him," Townsend writes, what she really means is "I have to respect his socioeconomic status." Meanwhile, the men in Townsend's study vastly preferred pretty women in Burger King uniforms to unattractive women in expensive high-status garb. Before we condemn these men as hopelessly superficial, let's look at some recent research by Judith H. Langlois and Lori A. Roggmann. These researchers digitized the facial features of ninety-six female students, averaged them into a composite picture, and then presented all ninety-six photos plus the composite to male students. The men rated the composite "average" face in the top five most attractive faces in the study. Only four real women scored higher. By contrast, the men gave low ratings to faces that were extreme in any measure. Men, it appears, are most attracted to women whose looks are symmetrical and, in a biological sense, truly average. An extension of this test clarifies men's attraction to average looks versus "beauty." When researchers presented men with three composites of female faces, the most popular turned out not to be a true average of real faces but instead a composite of composites, with digitized, deliberately exaggerated "desirable" (and often childlike) features--full lips, high cheekbones, small chin, widely spaced eyes--that the men had focused on in their earlier top fifteen real choices. The upshot is that although men prefer biologically average women, they also can be seduced by unreal, hyperattractive beauty embodied most in childlike female traits. Even more striking evidence exists of men's tendency to focus on the physical. In a survey of college students asking for characteristics they found most attractive in the opposite sex, women students named intelligence and a sense of humor as the top traits they sought in men. Men said they focused most on a woman's breasts. "It turns out," concludes David M. Buss after reviewing his thirty-seven cultures, "that a woman's physical appearance is the most powerful predictor of the occupational status of the man she marries. A woman's appearance is more significant than her intelligence, her level of education or even her original socioeconomic status in determining the mate she will marry." Thus, in contrast to women, whose mating priorities revolve around security and certain behavioral qualities in men, men are apparently seeking genetically sound breeding stock, and they are using physical, not behavioral, cues to find it. The bottom line? According to Buss, the bottom line is "men possessing what women want--the ability to provide resources--are best able to mate according to their preferences." Are women justified in focusing first on men's success? Children of good Ache hunters do have a higher survival rate than those of mediocre hunters. The same holds true for professional parents in England; their adolescent children averaged two inches taller and also matured earlier than those of unskilled laborers, regardless of family size. American wives of wealthier men have more and healthier children than middle-class wives do. In short, women seem to know what they are doing--at least where their children's health is concerned--when they seek men with money. "A successful man is one who makes more money than his wife can spend," actress Lana Turner once wryly pointed out. "A successful woman is one who can find such a man." What all this implies is that the priorities of American men and women differ drastically. Consider, for example, what 15,000 husbands admitted to Willard F. Harley, Jr., about their top five priorities in a wife. These men wanted sexual fulfillment, recreational companionship, an attractive spouse, domestic support, and admiration. Meanwhile, women's top five priorities in a husband were affection, conversation, honesty and openness, financial support, and family commitment. (Another 4,500 women interviewed by feminist Shere Hire matched Harley's findings.) In His Needs, Her Needs Harley concludes, "His needs are not hers." No argument there, but the first three priorities that women listed are not as intimate and cozy as they may seem. Affection, conversation, and honesty and openness are not merely sensitive and pleasant; they also are the strongest reassurances by a husband that his financial support and family commitment are predictable and secure. A lack of affection and open communication, on the other hand, is a glaring signal that a husband may be wandering. The divergent priorities of men and women tumble into a notoriously widespread failure of the sexes to speak the same language. In You Just Don't Understand: Women and Men in Conversation , linguist Deborah Tannen notes that from childhood, women use language to seek confirmation and to reinforce intimacy. Men use it to guard their independence and to negotiate status. The sexes' purposes for language diverge so much, notes Tannen, that messages assumed by both parties but never spoken far exceed those that are spoken. Men and women are normally at such cross-purposes verbally, she adds, that they often walk away from the same conversation with entirely different impressions and opinions of what was said. While the paradox of men and women who use the same language but remain mutually unintelligible is no laughing matter, for men and women, neither is laughing itself. Psychologist Robert R. Provine found that less than 20 percent of conversational laughter is "a response to anything resembling a formal effort at humor." Instead, laughter seems to work more as a contagious social lubricant. When we hear someone laugh, we laugh, and generally we feel better. But, as might be guessed, men and women differ in how they "use" laughter. In conversations, women laugh far more than men. "Female speakers laugh 127 percent more than their male audience," Provine reports. "In contrast, male speakers laugh about 7 percent less than their female audience. Neither males nor females laugh as much to female speakers as they do to male speakers." The trend for women to laugh more than twice as much as men during a conversation between them seems to be cross-cultural. And laughter itself tends to be disarming, even ingratiating. This difference between men and women poses several questions, not the least of which are why is this so and, perhaps more important, is there something wrong here? Playing by the Same Rules but in Two Different Games A decade ago, only 7 percent of American Ph.D.'s in engineering, 10 percent in computer sciences, and 16 percent in the physical sciences and math were awarded to women. Recently, the prestigious U.S. National Academy of Sciences selected sixty new members, only five of whom were women. And, whereas 68 percent of men teaching science in U.S. universities hold tenure, only 36 percent of female science professors do. Moreover, women today hold only 3 percent of the top executive jobs in U.S. companies. Is this gulf between what men and women have achieved in these areas due to boys having been encouraged and girls not? Yes, say feminist Irene Frieze and four women psychologist colleagues, who believe that these differences result from entrenched sexism aimed at "training women for nonachievement." They note that "the majority of women, even professional women, currently tend to put family concerns first. This means that women generally are not as productive nor as successful as men." Perhaps. But before we accept the conclusion that women are more concerned about their families than their careers only because society forces or tricks them into it, we should ask, Do women decide for other reasons that their natural and most rewarding talents lie outside the realms of mathematics, hard science, and capitalistic business? In fact, most women realize that a professional career will conflict with raising children. One study found that the mother-toddler bond was weaker in working mothers than in nonworking mothers. Toddlers with working mothers also felt and acted measurably more negative (bratty, uncooperative, disobedient) by the time they started kindergarten. In addition, Frieze and her colleagues present data suggesting that most professional women consider raising a family to be the top criterion for "success." Hence a mother who puts her preschool children before her career may not be making a less "successful" or less "productive" decision than one who chooses to work or chooses not to be a mother at all. Strangely, however, Frieze and her colleagues ignore what American professional women actually say they want most (a family) and instead base their definition of "successful" and "productive" on the criteria of Western men. These writers are not alone in this illogic, nor are their views extreme. Feminist Germaine Greer says that women's lack of "success" is due to men's having "castrated" them and forced them to become vapid, self-sacrificing sex objects. Moreover, she notes, "the `normal' sex roles that we learn to play from our infancy are no more natural than the antics of a transvestite." The only real success women can know, Greer insists, is by beating men at their own game. She says that the game women now play is sick: "The intimacy between mother and child is not sustaining and healthy." To Greer, marriages are disasters, and nuclear families are unhealthy for children, who would be better off raised en masse by trained women, much as Friedrich Engels prescribed in his communist manifesto. Though interesting reading, these explanations for sex differences are wrong. Most of us agree that no matter what a woman's priorities may be, double standards and sexism are targets deserving of reform. But the more we know about these targets, the more elusive they become, especially for women scientists trying to sort out the effects of biology and those of socialization. "These women [scientists] are doing a balancing act of formidable proportions," writes physical anthropologist Melvin Konner in The Tangled Wing: Biological Constraints on the Human Spirit . They continue to struggle, in private and in public, for equal rights and equal treatment for people of both sexes; at the same time they uncover and report evidence that the sexes are irremediably different--that after sexism is wholly stripped away, after differences in training have gone the way of the whalebone corset, there will still be something different, something that is grounded in biology. That "something different" seems to be that most women are born programmed to want to raise a family far more than they are driven to wrestle in the political arena. But raising a family in America in the Ozzie and Harriet mode is impossible for most people now that only one job in five pays enough to support a family of four. Hence most married mothers with young children must work, and to do this they often must compete with male workers. The dilemma produced by working for a living and raising offspring is an age-old problem faced by most female social primates. But the eye-opener in relation to men's violence is how most human females throughout history have solved this problem: by marrying males able and willing to support and protect them. Yet even in hunter-gatherer societies, husbands rarely earn enough to support a woman and their offspring fully. Thus most mothers also have to work, usually by gathering plant foods for the family larder. In modern society, working mothers find it extremely demanding to perform all the tasks of marriage, motherhood, managing a household, and succeeding in an economic career simultaneously. Not surprisingly, this leads to marital conflict: over a woman's dashed expectations when she finds she must work (and do everything else) despite her husband's income, or over a husband's dashed expectations when his wife cannot (or will not) perform all the roles demanded of her. Such conflicts, usually over money, contribute to divorce in half of all marriages throughout the world. If being successful as a wife, mother, and career woman seems like a hopeless catch-22, good. It should. In truth, mastering this challenge is possible only for an exceptionally adept woman. Meanwhile, the less spectacular majority give working women a bad rap, and they add fuel to the perceived "male conspiracy" to uphold the sexist professional double standard. The true cause of the professional double standard is not a male conspiracy. It is simple competition emerging from men's instinctive reproductive strategies. As we have seen, men make themselves attractive to women--and boost their odds of raising a family--by economically outcompeting everyone who crosses their path, male or female, whether by hunting elephants more cleverly or by inside trading. Conversely, a woman who pursues an economic career not only absents herself from raising a family but also makes herself less attractive to men interested in marrying a future mother who will raise their children carefully and not be financially independent. On top of all this, the working mother also poses additional direct competition to working men, who, in typical male fashion, do what they can to squash that competition. None of this is an American, or even a First World, syndrome. People in all known cultures encourage men more than women to perform in economics, politics, and war. That ten times more men than women worldwide are politicians is no coincidence. Nor is it by chance alone that people worldwide encourage women far more than men to be good nurturers. All societies do this. These sex differences are basic biology for mammals, which have been shaped by natural selection for maximum individual reproductive success. No matter how well a man might protect, console, teach, or play with an infant, he cannot nurse it, hence women's instincts to perform most nurturing. But for reasons that will become all too clear later in this book, unmarried women (outside of socialistic government programs) have less success than married women in raising their offspring. Anthropology reveals that the most reproductively successful women have the assistance of a husband who sustains and protects both mother and child. Germaine Greer's claims notwithstanding, no other arrangement has ever improved on, or even matched, the nuclear family and its extensions in maximizing a woman's reproductive success. One clue to why this is so is children themselves. Most children are resilient enough to bounce back from near starvation or disease. But emotional distress due to poor nurturing depresses secretion of growth stimulating hormone to the point where unloved children raised communally not only fail to thrive but actually stop growing. "Communally reared children," admits feminist Alice Rossi, "far from being liberated, are often neglected, joyless creatures." In short, women are urged by their psyches to seek reproductive success via very different strategies than men. And although we may convince men and women to play by the same rules, they are still playing very different games. Are Men Born to Be Bad? Despite all scientific research, untangling the biology of human behavior is no easy task. Nor is the quest to understand humans helped by our own social behavior in the United States. America breeds alternative social values--often with junk food-like ingredients--and pop psychologies with the life spans of mayflies. Americans have subjected themselves to experiment after experiment: utopias, communes, free love, Skinner boxes, single parents, welfare, socialism, God as business, even mass suicide to hitch a ride on an imagined alien spaceship riding shotgun behind comet Hale-Bopp. For many people, TV has become a virtual alternative to having a life. When the sitcom Seinfeld ran its final episode, for example, viewers admitted that their lives would be fundamentally changed by no longer being able to tune in. Our quest to identify human nature also is not helped by the grim reality that even our most basic social institutions confuse many college professors. For example, the fact that husbands worldwide work to support their wives and children perplexed anthropologist Margaret Mead. "What's distinctive about the human family," Mead wrote in 1949 in Male and Female , "lies in the nurturing behaviour of the human male, who among human beings everywhere helps provide food for women and children." Mead's confusion? "We have no indication that man the animal, man unpatterned by social learning, would do anything of the sort.... Male sexuality seems originally focused to no goal beyond immediate discharge; it is society that provides the male with a desire for children." More than any other anthropologist, Mead indoctrinated most of modern America with the idea that human nature does not exist, except inasmuch as we are all social learners. Mead gained her credibility by parlaying her three months of interviewing fifty Samoan girls maturing from childhood to womanhood into Coming of Age in Samoa: A Psychological Study of Primitive Youth for Western Civilization . This 1928 book was used in more anthropology classes than any other book in history. Why? Because in it, free love flourished in a guiltless, pacifistic society, where violence existed only in occasional stylized war, almost as an afterthought. Samoans, Mead told us, lived in a societal paradise. Mead's message? We could, too. The "right" cultural upbringing could free us of the evils of violence, sexism, sexual guilt, dysfunction, and jealousy engendered by Western civilization. Inadvertently perhaps, Mead kicked off America's era of social junk food. She literally derailed any chance of our understanding male violence until field observations of the great apes woke us up. Her ideas, however, still shape education and politics in America despite the known fact that every major assertion she made about Samoan sex and violence is, and was then, false--but only partly because some of the girls Mead interviewed were simply having fun by telling her fibs about their exaggerated sex lives. In fact, Samoans in 1925-1926 commonly raped girls. Brothers assiduously guarded the highly prized virginity of their sisters. Sexual jealousy led to mutilation and murder. Samoan men killed in warfare, often in staggering numbers. By contrast, New York City was more idyllic. In short, because Mead ignored biology in favor of her own wishful thinking--and made things worse by spending only twelve weeks on the job, by neither living with nor interviewing Samoan adults, and by not even learning to speak Samoan very well--many of her major conclusions on human behavior were on a par with the flat-earth hypothesis. For example, male nurturing is not, as Mead claimed, unique to men. Most male birds and many male social mammals are paragons of child support. A male African hornbill walls up his female partner inside a tree hole for months on end, from the time she lays her eggs until the nestlings are grown, to protect them all from predators. The male works unceasingly, day after day, to gather prey, which he feeds to the female through a slit left open in the mud wall they built. He also feeds their growing nestlings. If the male dies, the entire family may die. Males of other species work just as hard for their families. None was taught to do so by its "society." Nor do men nurture their families merely by imitating other husbands and fathers (although this certainly helps). The compulsion men feel to invest in their children is universal; it is yet another instinct, sculpted by sexual selection, that is deeply rooted in the male psyche. Ironically, it is physical anthropology (anathema to many cultural and social anthropologists such as Mead) that provides much of the evidence for human instincts. All hunter-gatherers divide labor by sex: women forage for plants (carbohydrates), while men hunt or fish (protein). Our marital patterns today are not all that different: Just replace the meat or fish that "man the hunter" risks his life to wrest from the wilds with the money that "man the worker" risks an ulcer and death on the freeway to bring home from the job. Then replace the plants that "woman the gatherer" brings home with the additional cash that "woman the part-time worker" earns. A key point here is that, in the normal mating pattern of humans over the ages, men have been expected to bring in more or better resources (protein being superior to carbohydrates, for example) than women. This is how most men attract, and hold, most women. Even male chimps hunt for meat most often when a sexually receptive female is nearby. "If women didn't exist," financial giant Aristotle Onassis noted, "all the money in the world wouldn't have any meaning." After studying ethnographies worldwide, physical anthropologist Donald Symons concluded that the human psyche is genetically programmed to learn a sexual division of labor and roles, one that profits both men and women. But "hunting, fighting, and that elusive activity, `politics,'" adds Symons, "[are] highly competitive, largely male domains." Hunting, fighting, and politics, of course, are the primary arenas in which men wrest from other men control of resources critical to attracting and supporting women. And men often do this violently, by robbing, murdering, and waging war--by no-holds-barred mayhem. But the origin of men's violence is not a question of nature versus nurture. Instead, nurture is genetically programmed by nature. As this book will show, women and men are designed by nature to be different in sex and in gender---the most basic ruling elements of the human psyche and self-identity--and they are also instinctively designed to learn appropriate and competitive gender roles culturally through parental nurturing as adaptations to help them win in all forms of reproductive competition with other people of the same sex. Men's violence emerges as a reproductive strategy shaped by each facet of this process: nature, sex, nurture, and gender . Gender roles allow us to survive, compete, mate, and raise our own children. Even the great apes share this need and drive to be programmed with gender behaviors; nongenderized apes either fail to mate or kill their infants by improper care. Gender is, in fact, our best example of how nature and nurture work together to shape us. Hence it is no coincidence that men and women are designed differently in body and mind to best execute gender-specific roles. Failing to identify with and perform the appropriate gender behaviors may result in natural selection culling one's "fail-to-genderize" genes. Indeed, it is certain that during most of human existence, failing to be violent enough seriously reduced a man's reproductive success. Now we return to the big question: are men born to be lethally violent? The answer is yes. Aggression is programmed by our DNA. A Dutch team even identified a gene for hyperaggression in men. But even normal men are born killers. Melvin Konner surveyed 122 societies and found that weapon making was done by men, and never by women, in all of them. In another study of 75 societies, men in all of them even dreamed more violent dreams than women. Konner concludes that "men are more violent than women." The statistics on homicide confirm this conclusion. And as we will see, although socialization does help men to choose their weapons, socialization is not what causes men to use those weapons to kill so much more often than women. What does cause men to kill, rape, rob, and wage war is something far more basic--and is something utterly alien to most women. Yes, men are born to be bad--but not always bad, rarely gratuitously bad, and rarely bad in cold blood. Instead, most male mayhem erupts from a cascade of emotions far more primitive than those of the first cave man. Copyright © 1999 Michael P. Ghiglieri. All rights reserved.
