Everything that every individual has ever done in all of human history and prehistory establishes the minimum boundary of the possible. The maximum, if any, is completely unknown.
—JEROME BARKOW, LEDA COSMIDES, AND JOHN TOOBY, The Adapted Mind
UNDERSTANDING HUMAN MATING requires recognizing that our strategies are multiple, flexible, and contingent on context, culture, and personal condition. Our complex psychological adaptations, designed by a long history of evolution, give us a versatile strategic repertoire for coping with the challenges of mating. With this repertoire, we tailor our mating decisions to individual and social circumstances in a valiant effort to fulfill our desires and, ideally, fulfill the desires of special others. In the mating marketplace, no behavior is inevitable or genetically preordained—neither infidelity nor monogamy, neither sexual violence nor sexual tranquility, neither jealous guarding nor sexual indifference. Men are not doomed to have affairs because of an insatiable lust for sexual variety. Women are not doomed to dismiss men who lack status and prestige. We are not slaves to sex roles dictated by evolution. Knowledge of our multifaceted desires and the costs and benefits of different strategies gives us the possibility of choosing from our wide-ranging mating menu.
Understanding why sexual strategies have evolved and the adaptive problems they were designed to solve provides a powerful fulcrum for changing behavior. Just because humans have physiological adaptations that cause us to grow calluses in response to repeated friction to the skin, for example, it is not inevitable that humans must develop calluses. We can and do create more friction-free environments. Similarly, knowing that jealousy functions to protect paternity for men and the commitment of a mate for women brings into focus the conditions most likely to trigger jealousy, such as cues to sexual and emotional infidelity. In principle, just as we can create environments that minimize friction, we can create jealousy-free relationships. Those who practice polyamory strive to do precisely that, and they sometimes succeed, although it would be naive to think that shutting down such strong emotional circuits is simple or easy.
Throughout this book I have used empirical studies of mating as the building blocks for a theory of human mating psychology. Although I have not hesitated to speculate when warranted, it is anchored in evidence. Now I will go beyond the scientific findings to describe what I see as their broader implications for social interactions in general, and for relations between men and women in particular.
Differences Between the Sexes
Insight into the relations between men and women must penetrate the riddle of gender similarities and differences. Because women and men alike have faced many similar adaptive challenges over evolutionary history, all humans share many psychological solutions. Both sexes sweat and shiver to regulate body temperature. Both sexes place a tremendous value on intelligence and dependability in a lifetime mate. Both seek long-term mates who are cooperative, trustworthy, and loyal. And both desire mates who will not inflict crushing costs on them. We are all of one species from the same planet. Recognition of our shared psychology and shared biology is one step toward producing harmony between the sexes.
Against the backdrop of these shared adaptations, gender differences stand out in stark relief and demand explanation. Men and women differ in their psychology of mating solely and specifically in the domains where they have faced recurrently different adaptive problems over the long course of evolutionary history. Because ancestral women bore the lion’s share of responsibility for nourishing their infants, women rather than men have lactating breasts. Because fertilization occurs internally within women, ancestral men confronted the problem of uncertainty over their fatherhood. As a consequence, men have evolved particular mate preferences for sexual loyalty, a psychology of jealousy centered on sexual infidelity, and a proclivity to withdraw commitment when cuckolded, all of which differ in design from the mating psychology of women.1
Some of these gender differences may be unpleasant. Many women dislike being treated as sex objects or valued for qualities largely beyond their control, such as youth and beauty, although some exploit these desires for their own ends. Many men dislike being treated as success objects or valued for the size of their investment portfolio and the importance of their status in a competitive world, although they too sometimes exploit these desires for their own ends. It is painful to be the wife of a man whose desire for sexual variety leads him to sexual infidelity. It is painful to be the husband of a woman whose desire for emotional closeness leads her to seek intimacy in the arms of another man. For both genders it is distressing to be regarded as undesirable merely because one does not possess qualities that the other prefers in a mate.
To assume that men and women are psychologically the same, as was generally done in traditional social science and still is in some out-of-date scientific circles, goes against what we now know about our evolved sexual psychology. Given the power of sexual selection, under which each sex competes for access to desirable mates, it would defy scientific logic to find that men and women were psychologically identical in aspects of mating about which they have faced different adaptive challenges for millions of years. At this point in history, we can no longer doubt that men and women differ in their preferences for a mate: primarily for youth and physical attractiveness in one case, and for status, maturity, success, protection, and economic resources in the other. Men and women also differ in their proclivities for casual sex without emotional involvement, in their desire for sexual variety, and in the nature of their sexual fantasies.
Internet dating sites reveal modern expressions of our evolved sexual psychology. Tinder is deluged with more men than women who want casual sex. AshleyMadison.com appeals mostly to married men who seek sexual variety. SeekingArrangement.com caters to men with status and resources and women with youth and beauty who want to parlay their respective assets.
Men and women face different forms of interference with their preferred sexual strategies and so differ in the kinds of events that trigger powerful emotions such as anger and jealousy. Men and women differ in their tactics to attract mates, to keep mates, to eject mates, and to replace mates. These differences are universal features of our evolved strategies. They govern social interactions and fundamental relationships between individual women and men.
Some people complain about these differences, or deny that they exist despite the scientific evidence, or wish that they would cease to exist. But wishes and denials will not make psychological gender differences disappear, any more than they will make men’s beard growth or women’s breast development disappear. Harmony between men and women will be approached only when these denials are swept away and we squarely confront the differing desires and strategies of each.
The Evolutionary Origins of Patriarchy
The evolution of gender differences has unavoidable implications for feminism, as noted by feminist evolutionists such as Patricia Gowaty, Maryanne Fisher-MacDonnell, Jane Lancaster, Barbara Smuts, and Griet Vandermassen. According to the tenets of many feminists, patriarchy—defined roughly as the control of power and resources by men and the physical, psychological, and sexual subordination of women—is a major cause of the battle between the sexes. Oppression through subordination and the control of resources is said to be motivated by men’s desire to control women’s sexuality and reproduction. Human sexual strategies bear out major elements of this feminist viewpoint. Men indeed tend to control resources worldwide, although this is changing in many cultures that strive for economic equality. Individual men do oppress individual women not only through their control of resources but sometimes through sexual coercion and violence. Men’s efforts to control women do center on women’s sexuality and reproduction. And women, as well as men, often participate in perpetuating this oppression.2
An evolutionary perspective on sexual strategies provides valuable insights into the origins and maintenance of men’s control of resources and men’s attempts to control women’s sexuality. A startling consequence of sexual strategies, for example, is that men’s dominant control of resources worldwide can be traced, in part, to women’s preferences in choosing a mate.3 These preferences, operating repeatedly over thousands of generations, have led women to favor men who possess status and resources and to disfavor men who lack these assets. Ancestral men who failed to acquire such resources failed to attract women as mates.
Women’s preferences thus established a critical set of ground rules for men in their competition with one another. Modern men have inherited from their ancestors psychological mechanisms that not only give priority to resources and status but also lead men to make great sacrifices and take great risks to attain resources and status. Men who fail to give these goals a high personal priority fail to attract mates.
One of men’s key strategies is to form coalitions with other men. These organized alliances give men the power to triumph over other men in their quest for resources and sexual access. In animals, strong coalitions are seen among baboons, chimpanzees, and dolphins.4 Male bottlenose dolphins, for example, form coalitions to herd females and thereby gain greater sexual access than would be possible by operating alone.5 Among chimpanzees, our closest primate relative, males form alliances to increase their chances of victory in physical contests with other chimpanzees, their status in the group hierarchy, and their sexual access to females. Rarely can a male chimpanzee become the dominant member of the troop without the aid of allies. Solitary males without coalition partners are at great risk of being brutally attacked and sometimes killed by males from other groups.6
Human males, too, form alliances for gaining resources such as large game, political power within the group, ways to defend against the aggression of other coalitions of men, and sexual access to women.7 The survival and reproductive benefits derived from these coalitional activities constituted tremendous selection pressure over human evolutionary history for men to form alliances with other men. Since ancestral women did not hunt large game, declare war on other tribes, or attempt to forcibly capture men from neighboring bands, they did not experience equivalent selection pressure to form coalitions.8 Although women do form coalitions with other women for the care of the young and for protection from sexually aggressive men, these are weakened whenever a woman leaves her kin group to live with her husband and his clan. The combination of strong coalitions among men and somewhat weaker coalitions among women, according to Barbara Smuts, may have contributed historically to men’s dominance over women.9 My view is that women’s preferences for a successful, ambitious, and resource-capable mate coevolved with men’s competitive mating strategies, which include risk taking, status striving, derogation of competitors, coalition formation, and an array of individual efforts aimed at surpassing other men on the dimensions that women desire. The intertwining of these coevolved mechanisms in men and women created the conditions for men to dominate in the domain of resources.
The origins of men’s control over resources is not simply an incidental historical footnote of passing curiosity. Rather, it has a profound bearing on the present, because it reveals some of the primary causes of men’s continuing control of resources. Women today continue to want men who have resources, and they continue to reject men who lack resources. These preferences are expressed repeatedly in dozens of studies conducted on tens of thousands of individuals in scores of countries worldwide. They are expressed countless times in everyday life. In any given year, the men whom women marry earn more than men of the same age whom women do not marry. Even professionally successful women who do not really need resources from a man are reluctant to settle for a mate who is less successful than they are. Women who earn more than their husbands seek divorce more often, although this trend appears to be changing, at least within America. Men continue to compete with other men to acquire the status and resources that make them desirable to women. The forces that originally caused the resource inequality between the genders—women’s mate preferences and men’s competitive strategies—are the same forces that contribute to maintaining resource inequality today.10
Feminists’ and evolutionists’ conclusions converge in their implication that men’s efforts to control female sexuality lie at the core of their efforts to control women. Our evolved sexual strategies account for why this occurs, and why control of women’s sexuality is a central preoccupation of men.11 Over the course of human evolutionary history, men who failed to control women’s sexuality—for example, by failing to attract a mate, failing to prevent cuckoldry, or failing to retain a mate—experienced lower reproductive success than men who succeeded in controlling women’s sexuality. We come from a long and unbroken line of ancestral fathers who succeeded in obtaining mates, preventing their infidelity, and providing enough benefits to keep them from leaving. We also come from a long line of ancestral mothers who granted sexual access to men who provided beneficial resources.
Feminist theory sometimes portrays men as being united with all other men in their common purpose of oppressing women.12 But the evolution of human mating suggests that this scenario cannot be true, because men and women compete primarily against members of their own gender. Men strive to control resources mainly at the expense of other men. Men deprive other men of their resources, exclude other men from positions of status and power, and derogate other men in order to make them less desirable to women. Indeed, the fact that nearly 70 percent of all homicides are inflicted by men on other men reveals the tip of the iceberg of the cost of competition to men.13 The fact that men on average die years earlier than women in every culture is further testimony to the penalties men pay for this struggle with other men.
Women do not escape damage inflicted by members of their own sex.14 Women compete with each other for access to high-status men, have sex with other women’s husbands, and lure men away from their wives. Mate poaching is a ubiquitous sexual strategy of our species. Women slander and denigrate their rivals and are especially harsh toward women who pursue short-term sexual strategies. Women and men are both victims of the sexual strategies of their own gender and so can hardly be said to be united with their own gender for some common goal.
Moreover, both men and women benefit from the strategies of the opposite sex. Men lavish resources and protection on certain women, including their wives, their sisters, their daughters, and their mistresses. A woman’s father, brothers, and sons all benefit from her selection of a mate who is flush with abundance. Contrary to the view that men or women are united with all members of their own sex for the purpose of oppressing the other sex, each individual shares key interests with particular members of each sex and is in conflict with other members of each sex. Simple-minded views of a same-sex conspiracy have no foundation in reality.
Although today men’s sexual strategies contribute to their control over resources, the origins of their strategies cannot be separated from the evolution of women’s desires. This analysis does not imply that we should blame women for the fact that men control resources or blame men for their relentless pursuit of them. Rather, if harmony and equality are to be achieved, women and men both must be recognized as linked together in a spiraling causal chain of this coevolutionary process. This process started long ago with the evolution of desire and continues to operate today through our strategies of mating.
Diversity in Mating Strategies
Differences in the desires of men and women represent an important part of the diversity within the human species, but there is tremendous variability within each sex as well. Although more men than women are inclined to pursue purely casual sexual relationships, some men remain exclusively monogamous for life and some women find polyamory, casual sex, or a mixed mating strategy preferable to monogamy. Some men seek women for their economic resources, and some women seek men for their looks, despite average trends to the contrary. Although most men and most women are sexually attracted to the other gender, some are attracted to members of their own gender, some to both, and some to neither. These differences within each gender cannot be dismissed as statistical flukes. They are crucial to understanding the rich repertoire of human mating strategies.
Sexual diversity hinges on the individual circumstances that favor each person’s choice of one strategy over another within their repertoire—a choice that may not be consciously articulated. For example, Aka men favor a mating strategy of high parental investment when they lack economic resources.15 !Kung women favor serial mating in circumstances in which they are sufficiently desirable to continue attracting men who are willing to invest.16 Our mate value—how desirable we are in the mating market—influences the degree to which we can translate our desires into actual mating outcomes. No mating strategies, however deeply rooted in our evolved psychology, are invariably expressed regardless of social context or regardless of mate value. Knowledge of the contexts that facilitate and impede each sexual strategy aids our understanding of the diversity of mating behaviors within and between the genders.
Knowledge of this diversity leads one to scrutinize certain value judgments for the selfish interests that may be driving them. In Western society, lifelong monogamy is often held up to be the ideal. Anyone who does not conform to this practice is regarded as deviant, immature, sinful, or a failure. Such a judgment may turn out to be a manifestation of the underlying sexual strategies of the person who upholds it. It is often in the best interests of a woman, for example, to convince others of the ideal of lifelong love. Women pursuing a short-term mating strategy pose a threat to monogamous women, siphoning off the resources, attention, and commitment of their long-term mates. It is often in the best interests of a man to convince others to adopt a monogamous strategy, even if he fails to follow it himself. Promiscuous men usurp single men’s mating opportunities and threaten to poach already mated women. Our sexual morality, in short, is a key component of our evolved mating strategies.
The short-term sexual strategies of both genders originate deep in human evolutionary history. Evolutionary accounts that emphasize the sexually indiscriminate man and the sexually coy woman grossly overstate the case. Just as men have the capacity for commitment as part of their strategic repertoire, women have the capacity for casual sex within theirs, and they in fact pursue it when they perceive that it is to their advantage to do so.
For a century after Darwin proposed the theory of sexual selection, it was vigorously resisted by male scientists, in part because they presumed that women were passive in the mating process. The proposal that women actively select their mates and that these selections constitute a powerful evolutionary force was thought to be science fiction rather than scientific fact. In the 1970s, scientists gradually came to accept the profound importance of female choice in the animal and insect world, and in the 1980s and 1990s scientists began to document within our own species the active strategies that women pursue in choosing and competing for mates. But in the early decades of the twenty-first century, some stubborn holdouts continue to insist that women have but a single mating strategy—the pursuit of a long-term mate.
Scientific evidence suggests otherwise. The fact that women who are engaged in casual sex as opposed to committed mating shift their mating desires to favor a man’s extravagant lifestyle, his physical attractiveness, his masculine body, and even his risk-taking, cocky “bad-boy” qualities tells us that women have specific psychological mechanisms designed for short-term mating. The fact that women who have extramarital affairs often choose men who are higher in status than their husbands and tend to fall in love with their affair partners reveals that women have adaptations for mate switching. The fact that women shift to brief liaisons under predictable circumstances, such as a scarcity of men capable of investing in them or an unfavorable ratio of women to men, tells us that women have specific adaptations designed for shifting from long-term to short-term mating strategies.
People often condemn as immoral the frequent switching of mates and other sexually uninhibited activities. And it often serves their interests to promulgate this view of morality to others. Our sexual morality stems from our evolved sexual strategies. From a scientific point of view, however, there is no moral justification for placing a premium on a single strategy within the collective human repertoire. Our human nature is found in the entire repertoire of our sexual strategies. Recognition of the rich diversity of desires takes us one step closer to harmony.
Cultural Variation in Mating
Cultural variation represents one of the most fascinating and mysterious aspects of human diversity. Members of different societies differ dramatically on some qualities, as in their desire for virginity in a marriage partner. In China in the 1980s, for example, nearly every individual, both male and female, viewed virginity as indispensable in a mate. Nonvirgin Chinese were virtually unmarriageable. Chinese culture has changed, however, over the past thirty years: although virginity is still valued, research from my lab found that its importance in mate preferences has gradually declined.17 In Scandinavian countries, such as Sweden and Norway, chastity was, and still is, unimportant in a mate. This kind of cultural variability poses a puzzle for all theories of human mating.
Evolutionary psychology focuses on early experiences, parenting practices, and other current social and ecological factors to explain variability in mating strategies. The psychologist Jay Belsky and his colleagues, for example, argue that harsh, rejecting, and inconsistent child-rearing practices, erratically provided resources, and marital discord foster in children a mating strategy of early reproduction and rapid turnover.18 In contrast, sensitive, supportive, and responsive child rearing, combined with reliable resources and spousal harmony, foster in children a mating strategy of commitment marked by delayed reproduction and stable marital bonds. Children growing up in uncertain and unpredictable environments, in short, learn that they cannot rely on a single mate. They therefore opt for a sexual life that starts early and that inclines them to switch mates frequently. In contrast, children who grow up in stable homes with predictably investing parents opt for a strategy of permanent mating because they expect to attract a stable, high-investing mate. The evidence from children of divorced homes supports this theory. Such children reach puberty earlier, engage in intercourse earlier, and have more numerous sex partners than their peers from intact homes.
The sensitivity of mating strategies to early experiences may help to explain the differences in the value placed on chastity across cultures. In China, for example, marriages historically have been lasting and divorce has been rare, with parents investing heavily in their children over extended periods. In Sweden, many children are born out of wedlock, divorce is common, and fewer fathers invest consistently over time. Chinese and Swedes may select different sexual strategies from the universal human repertoire because of these early developmental experiences. Although the significance of early experiences requires further testing, the evidence so far supports the view that men and women both have casual mating, committed mating, mate poaching, and mate-switching strategies within their repertoires. The particular strategy they choose from this menu depends partly on their early experiences, which vary from culture to culture.
Differences between the relatively promiscuous Ache and the relatively monogamous Hiwi also illuminate the cultural variability of human sexual strategies. The different ratios of males to females in these two cultures may be the critical factor in eliciting a different sexual strategy. Among the Ache, there are approximately one and a half women for every man. Among the Hiwi, there are more men than women, although precise numbers are not available. The prevalence of available Ache women creates sexual opportunities for Ache men not experienced by Hiwi men. Ache men seize these opportunities, as evidenced by the high frequency of mate switching and casual affairs. Ache men can pursue a temporary sexual strategy more successfully than Hiwi men can. Hiwi women are better able than Ache women to secure a high investment from men, who must provide resources to attract and retain a mate.19 The cultural shifts witnessed today, such as the hookup culture on college campuses and in large urban settings and the rise of casual sex and online dating apps such as Tinder, probably reflect shifts in mating strategies as a function of a perceived or real sex ratio imbalance.
One key cultural variable centers on the presumptive mating system, especially monogamy and polygamy. Some Islamic cultures permit men to marry up to four wives, as specified in the Qur’an. In parts of Utah and Texas in the United States, some fundamentalist Mormon groups place no formal limits on the number of wives a man can marry, and a few marry more than a dozen. Even presumptively monogamous cultures are often effectively polygynous, with some men having multiple mates through serial marriage or affair partners. The more polygynous the culture, the more some men will be inclined to pursue high-risk tactics in an effort to gain status, resources, and mates, either in the current life or in aspirational notions of life after death. Just as mating is a key cause of violence among nonhuman animals from elk to elephant seals, mating and violence are inexorably linked in our own species. Evolved mating strategies are influenced by, and implemented within, these key cultural contexts.
Evolved mating mechanisms are central to understanding differences among cultures in sexual strategies. Cultures differ in the sexual opportunities available, the resources provided by their ecology, the ratio of men to women, and the extent to which they promote long-term versus casual mating. Our evolved psychological mechanisms are attuned to these cultural inputs. Cultural variations in mating reflect differences in the choices made from the whole repertoire of possible human sexual strategies, based in part on cultural input. Every living human has inherited the complete repertoire from successful ancestors.
Competition and Conflict in the Mating Arena
An unpleasant fact of human mating is that desirable people are always outnumbered by the many who desire them. Some men demonstrate a superior ability to accrue resources, have a more appealing body type, or are more highly skilled at ascending status hierarchies. Because women typically desire these men, they compete with each other to attract them. Only women high in mate value, however, succeed. Women of striking beauty are desired by many men, but only a few men prosper in attracting them. The qualities of kindness, intelligence, dependability, athleticism, looks, and economic prospects are all present in the same person only rarely. Most of us must settle for someone who has less than the full complement of desirable qualities.
These stark facts create competition and conflict within each gender that can be avoided only by opting out of the mating game entirely. The fundamental desires of mating, however, are not easily extinguished. The quest to fulfill these desires catapults people headlong into the arena of competition. People do not always recognize competition in its many guises. A man or woman buying the latest facial cream may not construe this attention to skin as competition. A woman or man participating in the latest fitness craze or working late into the night may not construe these actions as competition. But as long as people have mating desires and as long as people differ in the qualities desired, competition will be an inevitable aspect of human mating.
Conflict between the sexes is likewise not easily extinguished. Some men show a thoughtless insensitivity to women’s sexual psychology. Men sometimes seek sex sooner, more frequently, more persistently, or more aggressively than women want. Charges of sexual harassment and coercion are almost exclusively levied by women against men because of fundamental differences in the mating strategies of the two sexes. Men’s strategies conflict with women’s desires, causing anger and distress. Analogously, women spurn men who lack the desired qualities, causing frustration and resentment among the men who are rejected. Women interfere with men’s sexual strategies as much as men interfere with women’s, although perhaps they do so in less brutal and coercive ways.
Conflict within couples is also impossible to eliminate entirely. Although some couples live harmonious, happy lives together, no couple experiences a complete absence of conflict. The conditions that trigger conflict are often unavoidable. A man who gets fired from his job because of factors beyond his control may find that his wife wants a divorce because he no longer provides the resources on which she partly based her mating decision. A woman with encroaching wrinkles, through no fault of her own, may find that her professionally successful husband desires a younger woman. Some conflict between the sexes is impossible to eliminate because the conditions that foster it cannot be avoided.
The fact that conflicts between men and women originate from our evolved mating psychology is disturbing to some people, partly because it contradicts widely held beliefs. Many of us have learned the traditional view that these conflicts are reflections of a particular culture whose practices perturb the natural harmony of human nature. But the anger that women feel when sexually coerced and the rage that men feel when cuckolded arise from our evolved mating strategies, not from capitalism, culture, patriarchy, or socialization. Evolution operates by the ruthless criterion of reproductive success, no matter how repugnant we may find the strategies produced by that process, and no matter how abhorrent the consequences of those strategies may be.
An especially destructive manifestation of conflict between members of the same gender is warfare, a recurrent activity throughout human history. Given men’s tendency to take physical risks in their pursuit of the resources needed for success at mating, it comes as no surprise that warfare is almost exclusively a male activity. Among the Yanomamö, there are two key motives that spur men to declare war on another tribe—a desire to capture the wives of other men and a desire to recapture wives that were lost in previous raids. When the American anthropologist Napoleon Chagnon explained to his Yanomamö informants that the United States waged war for principles such as freedom and democracy, they were astonished. It seemed absurd to them to risk one’s life for anything other than capturing or recapturing women.20
The frequency of rape during wars throughout the course of human recorded history suggests that the sexual motives of the Yanomamö men may not be atypical.21 Men worldwide share the same evolved psychology. The fact that there has never in history been a single case of women forming a war party to raid neighboring villages and capture husbands tells us something important about the nature of gender differences—that men’s mating strategies are often more violent than women’s.22 The sexual motivation underlying violence also reveals that conflict within a sex is closely connected to conflict between the sexes. Men wage war to kill other men, but women become sexual victims.
In everyday life in modern society, the battle between the genders occurs between individual men and women interacting with each other socially—in the workplace, at parties, on online dating sites, and at home. The selective exclusion of mates, for example, does not affect all people, only those who lack the desired characteristics. Sexual jealousy is a cost inflicted not by all men on all women but rather by particular men, such as those lower in desirability than their partners, in particular circumstances, such as instances of infidelity, on particular women, such as spouses rather than casual sex partners. Sexual coercion, to take another example, is perpetrated only by some men, notably those with the sociopathic traits of low empathy, high hostility, hypermasculinity, and exploitative predispositions. Most men are not rapists, and most would be unlikely to commit rape even if there were no risk of getting caught.23
There is no solidarity among all men or all women that creates conflict between the sexes. Rather, members of each gender generally favor a common set of strategies that differ in some respects from the strategies pursued by members of the other sex. It is possible to speak of conflict between the sexes because the ways in which men and women typically conflict result from the strategies they have in common with their own sex. Still, we must recognize that no man or woman is fundamentally united with his or her own gender, nor fundamentally at odds with members of the other gender.
We are empowered now, more than at any time in human evolutionary history, to shape our future. The fact that deception, coercion, and abuse stem from our mating strategies does not justify their perpetuation. By employing the evolved mechanisms that are sensitive to personal costs, such as our sensitivity to reputational damage and our fear of ostracism, we may be able to curtail the expression of the more damaging aspects of our mating strategies.
Cooperation Between the Sexes
Men and women have always depended on each other for transporting their genes to future generations. Committed mateships are characterized by a complex web of long-term trust and reciprocity that appears to be unparalleled in other species. In this sense, cooperation between the sexes reaches a pinnacle among humans. Our strategies for cooperation in mating define human nature as much as our evolved capacity for language and culture.
Sexual strategies provide us with some of the conditions that facilitate the achievement of lifelong love. Children, the shared vehicles by which genes survive the journey to future generations, align the interests of a man and a woman and foster enduring mating bonds. Parents share in the delights of producing new life and nurturing their children to maturity. They marvel together as the gift of their union partakes of life’s reproductive cycle. But children also create new sources of conflict, from disputes about dividing the child care to reduced opportunities for nighttime sexual harmony. No blessing is unmixed.
Sexual fidelity also promotes marital harmony. Any possibility of infidelity opens up a chasm of conflicting interests. Infidelity disrupts mating bonds and leads to breakups. Monogamy encourages prolonged trust between a man and a woman. If a woman is unfaithful, she may benefit by obtaining extra material resources, better genes to pass on to her children, or opportunities to trade up in the mating market. But the benefits that flow to her through infidelity come at a cost to her husband in a reduced certainty of paternity, a destruction of trust, and the potential long-term loss of his mate. A man’s infidelity may satisfy his lust for sexual variety or give him a momentary euphoria that mimics that of a polygynous man. But these benefits come at a cost to his wife as a portion of her husband’s love and investment is diverted to a rival. Lifelong sexual fidelity promotes harmony between a man and a woman, but it comes at a price for both in sacrificed external mating opportunities.
Fulfilling each other’s evolved desires is one key to harmony between a man and woman. A woman’s happiness increases when the man brings more economic resources to the union and shows kindness, affection, and commitment. A man’s happiness increases when the woman is more physically attractive than he is, and when she shows kindness, affection, and commitment.24 Those who fulfill each other’s desires have happier relationships, especially if there are no interested others in the mating pool who could fulfill them more completely. Our evolved desires, in short, provide the essential ingredients for solving the mystery of mating harmony.
Knowledge of the multiplicity of our desires may be the most powerful tool for promoting harmony. It is a crowning achievement of humankind that two unrelated individuals can bring all of their individual resources into a lifelong alliance characterized by the remarkable emotion of love. This happens because of the tremendous resources that each person brings to the relationship, the bounty of benefits that flow to those who cooperate, and the sophisticated psychological machinery that we have for forming enduringly valuable mateships. Some of these resources tend to be linked to a person’s gender, such as a woman’s reproductive viability or a man’s physical provisioning capacity. But mating resources typically transcend these reproductive essentials to include such capacities as protection from danger, deterrence of enemies, formation of friendships, tutoring of children, loyalty through thin and thick, and nurturance in times of setback. Each of these resources fulfills one of the many special desires that define our human nature.
A profound respect for the other gender should come from the knowledge that we have always depended on each other for the resources required for survival and reproduction. We have always depended on each other for the fulfillment of our desires. These facts may be responsible for the unique feeling of completeness that people experience when they become entwined in the intoxicating grip of love. A lifelong alliance of love is a triumphant achievement of human mating strategies.
Today we are confronted with novel sexual circumstances not encountered by any of our ancestors, including reliable contraception, fertility drugs, artificial insemination, cyber sex, online dating apps, breast implants, tummy tucks, sperm banks, and the capacity to genetically engineer “designer babies.” Our ability to control the consequences of our mating behavior is unprecedented in human evolutionary history and matched by no other species on earth. But we confront these modern novelties with an ancient set of mating strategies that worked in ancestral times and in places that are irretrievably lost. Our mating mechanisms are the living fossils that reveal who we are and where we came from.
We are the first species in the known history of three and a half billion years of life on earth with the capacity to control our own destiny. The prospect of designing our destiny remains excellent to the degree that we comprehend our evolutionary past. Only by examining the complex repertoire of human sexual strategies can we know where we came from. Only by understanding why these human strategies have evolved can we control where we are going.