To an extraordinary degree, the predilections of the investing sex—females—potentially determine the direction in which species evolve. For it is the female who is the ultimate arbiter of when she mates and how often and with whom.
—SARAH HRDY, The Woman That Never Evolved
WHAT WOMEN ACTUALLY want in a mate has puzzled both scientists and most men for centuries, for good reason. It is not androcentric to propose that women’s preferences in a partner are more complex and enigmatic than the mate preferences of either sex of any other species. Discovering the evolutionary roots of women’s desires requires going far back in time, before humans evolved as a species, before primates emerged from their mammalian ancestors, back to the origins of sexual reproduction itself.
One reason women are often more choosy about mates stems from the most basic fact of reproductive biology—the definition of sex. Remarkably, what defines biological sex is simply the size of the sex cells. Males are defined as the ones with the small sex cells, females as the ones with the large sex cells. The large female gametes remain reasonably stationary and come loaded with nutrients. The small male gametes are endowed with mobility and swimming speed.1 Along with differences in the size and mobility of sex cells comes a difference between the sexes in quantity. Men produce millions of sperm, which are replenished at a rate of roughly 12 million per hour. Women produce a fixed and unreplenishable lifetime supply of approximately 1 to 2 million ova. Of these follicles, most die. Only 400 ova mature to the point where they are capable of being fertilized.
Women’s greater initial investment does not end with the large egg. Fertilization and gestation, key components of human parental investment, occur internally within women. One act of sexual intercourse, which requires minimal male investment, can produce an obligatory and energy-consuming nine-month investment by the woman that forecloses other mating opportunities. Women then bear the exclusive burden of lactation, or breast-feeding, a calorically intensive investment that may last as long as three or four years.
No biological law of the animal world dictates that females invest more than males. Indeed, among some species, such as the Mormon cricket, pipefish seahorse, and Panamanian poison arrow frog, males invest more.2 The male Mormon cricket produces through great effort a large “spermatophore” that comes loaded with nutrients. Females compete with each other for access to the males that hold the largest spermatophores. Among these so-called sex-role reversed species, it is the males who are more discriminating about mating and females tend to be larger and more aggressive than the males. Among the more than 5,000 species of mammals, however, including the more than 250 species of primates, females bear the burden of internal fertilization, gestation, and lactation.
The great initial parental investment of women makes them an extraordinarily valuable, but limited, resource.3 Gestating, bearing, nursing, nurturing, and protecting a child are exceptional reproductive resources that women do not allocate indiscriminately. Nor can one woman dispense these resources to many men. There is only so much time and energy in the world, and those who require a lot of each to reproduce once can only reproduce so many times in a human life. This alone means female reproductive opportunities are limited: at most a given female can expect to reproduce a handful of times in her life. A given male, by contrast, can expect at most to reproduce as many times as there are available fertile females willing to have sex. Women’s reproductive resources are relatively precious. Those who have only a few shots at evolutionary success need to take those shots carefully.
Those who hold valuable resources do not give them away cheaply or unselectively. Because women in our evolutionary past risked enormous investment as a consequence of having sex, evolution favored women who were highly selective about their mates. Ancestral women suffered severe costs if they were indiscriminate—they experienced lower reproductive success, and fewer of their children survived to reproductive age. Women who were not careful to select healthy mates, for example, could bear unhealthy offspring and expose themselves and all their children to dangerous pathogens. Their offspring would die more often and reproduce less. A man in human evolutionary history could walk away from a casual coupling having lost only a few hours of time. His reproductive success was not seriously compromised. A woman in evolutionary history could also walk away from a casual encounter, but if she got pregnant as a result, she bore the costs of that decision for months, years, and even decades afterward. On the flip side, choosing a mate wisely produced a bounty of benefits ranging from good genes to a reliable provider.
Modern birth control technology has altered these costs and benefits. In places where women have access to reliable birth control, women can have short-term sexual encounters with less fear of pregnancy. And some modern women secure resources through their own professional successes, which can match and sometimes even far exceed those of the average man. But human sexual psychology evolved over millions of years to cope with ancestral adaptive problems, just as our food preferences evolved to meet ancestral food conditions. We still possess this underlying sexual psychology, even though our environment has changed.
The Many Facets of Desire
Consider an ancestral woman trying to decide between two men. One shows great generosity with his resources; the other is stingy. All else being equal, the generous man is more valuable to her than the stingy man. The generous man may share his meat from the hunt, aiding her survival. He may sacrifice his time, energy, and resources for the benefit of the children, furthering her reproductive success. In these respects, the generous man has higher value as a mate than the stingy man. If, over evolutionary time, generosity in men provided these benefits repeatedly and cues to a man’s generosity were observable and reliable, then selection would favor the evolution of a preference for generosity in a mate.
Now consider a more complicated and more realistic case in which men vary not just in their generosity but also in a bewildering variety of other ways that are also significant to the choice of a mate. Men vary in their physical prowess, athletic skill, ambition, industriousness, kindness, empathy, emotional stability, intelligence, social skills, sense of humor, kin network, and position in the status hierarchy. Men also differ in the costs they impose on a mating relationship: some come with children, bad debts, a quick temper, a selfish disposition, or a tendency to be promiscuous. In addition, men differ in hundreds of ways that may be irrelevant to women. Some men have navels turned in, others have navels turned out. A strong preference for a particular navel shape would be unlikely to evolve unless male navel differences were somehow adaptively relevant to ancestral women. From among the thousands of ways in which men differ, selection over hundreds of thousands of years focused women’s preferences laser-like on the most adaptively valuable characteristics.
The qualities people prefer, however, are not static. Because characteristics change, mate seekers must gauge the future potential of a prospective partner. A young medical student who lacks resources now might have excellent future promise. A very ambitious man may have already peaked and have little prospect of greater future success. Another man has children from a previous marriage, but because they are about to leave the nest, they may not drain his resources. Gauging a man’s mate value requires looking beyond his current position and evaluating his potential and his future trajectories.
Evolution has favored women who prefer men who possess attributes that confer benefits and who dislike men who possess attributes that impose costs. Each separate attribute constitutes one component of a man’s value to a woman as a mate. Each of her preferences tracks one component.
Preferences that favor particular components, however, do not completely solve the problem of choosing a mate. Women face further adaptive hurdles. First, a woman must evaluate her unique circumstances and personal needs. The same man might differ in value for different women. A man’s willingness to do a lot of direct child care, for example, might be more valuable to a woman who does not have kin around to help her than to a woman whose mother, sisters, aunts, and uncles eagerly participate. The dangers of choosing a man with a volatile temper may be greater for a woman who is an only child than for a woman with strong brothers and sisters around to protect her. The value of potential mates, in short, depends on the individualized, personalized, and contextualized perspective of the woman doing the choosing.
In selecting a mate, women must identify and correctly evaluate the cues that signal whether a man indeed possesses a particular resource. The assessment problem becomes especially difficult in domains where men are apt to deceive women. Yes, men sometimes lie. Some pretend to have higher status than they actually possess. Some feign greater commitment than they are actually willing to give.
Finally, women face the problem of integrating their knowledge about a prospective mate. Suppose that one man is generous but emotionally unstable. Another man is emotionally stable but stingy. Which man should a woman choose? Choosing a mate calls upon psychological mechanisms that make it possible to evaluate the relevant attributes and give each its appropriate weight in the whole. There are trade-offs. A masculine man might possess good genes but may be more likely to cheat. Some attributes are granted more weight than others in the final decision about whether to choose or reject a particular man. One of these heavily weighted components is the man’s resources.
Resource Potential
The evolution of the female preference for males who offer resources may be the most ancient and pervasive basis for female choice in the animal kingdom. Consider the gray shrike, a bird that lives in the Negev Desert of Israel.4 Just before the start of the breeding season, male shrikes begin amassing caches of 90 to 120 items of edible prey, such as snails, and other useful objects, such as feathers and pieces of cloth. They impale these items on thorns and other pointed projections within their territory. Females look over the available males and prefer to mate with those with the largest caches. When the biologist Reuven Yosef arbitrarily removed portions of some males’ caches and added edible objects to others, females shifted to the males with the larger bounties. Females avoided entirely males without resources, consigning them to bachelorhood. Wherever females show a mate preference, the male’s resources are often, although not always, the key criterion.
Among humans, the evolution of women’s preference for a committed mate with resources would have required three preconditions. First, resources would have had to be accruable, defensible, and controllable by men during human evolutionary history. Second, men would have had to differ from each other in their holdings or skill at resource acquisition, as well as in their willingness to invest those holdings in a woman and her children. If all men had possessed equal potential to acquire resources and shown an equal willingness to commit them, selection could not have favored a female preference for these qualities. Constants do not count in mating decisions. And third, the advantages of committing to one man would have had to outweigh the advantages of being with several men.
Among humans, these conditions are easily met. Territory and tools, to name just two resources, are acquired, defended, monopolized, and controlled by men worldwide. Men vary tremendously in the quantity of resources they command—from the poverty of the street bum to the riches of Bill Gates, Mark Zuckerberg, and Warren Buffett. Ancestral men similarly differed in their resource acquisition abilities, such as their hunting skills, a key ancestral analog of resource potential. Men today also differ widely in how willing they are to invest their time and resources in long-term mateships. Some men are cads, preferring to mate with many women while investing little in each. Other men are dads who prefer to channel all of their resources to one woman and her children.5
Women over human evolutionary history could often garner far more resources for their children through a single spouse than through several temporary sex partners. Men provide their wives and children with resources to an extent that is unprecedented among primates. Among most other primate species, for example, females must rely solely on their own efforts to acquire food, because males usually do not share food with their mates.6 Men, in contrast, provide food, find shelter, and defend territory. Men protect children. They tutor them in the art of hunting, the craft of war, the strategies of social influence, and even the game of mating. They transfer status, aiding offspring in forming reciprocal alliances later in life. These many benefits are unlikely to be secured by a woman from a casual sex partner. Not all potential husbands can confer all of these benefits, but over thousands of generations, when some men were able to provide some of these benefits, women gained a powerful advantage by preferring them as mates.
So the stage was set for women to evolve a preference for men with resources. But women needed cues that signified a man’s possession of those resources. These cues might have been indirect, such as personality characteristics that signaled a man’s upward mobility. They might have been physical, such as a man’s athletic ability or health. They might have included reputational information, such as the esteem in which a man was held by his peers. Economic resources, however, provided the most direct cue.
Women’s current mate preferences provide a window for viewing our mating past, just as our fears of snakes and heights provide a window for viewing ancestral hazards. Evidence from dozens of studies documents that modern American women do indeed value economic resources in mates substantially more than men do in mates. In a study conducted in 1939, for example, American men and women rated eighteen characteristics for their desirability in a mate or marriage partner, ranging from irrelevant to indispensable. Women did not view good financial prospects as absolutely indispensable, but they rated them as important. Men rated them as merely desirable but not very important. Women in 1939 valued good financial prospects in a mate about twice as highly as men, and this finding was replicated in 1956 and again in 1967.7
The sexual revolution of the late 1960s and early 1970s failed to change this gender difference. In an attempt to replicate the studies from earlier decades, I surveyed 1,491 Americans in the mid-1980s using the same questionnaire. Women and men from Massachusetts, Michigan, Texas, and California rated eighteen personal characteristics for their value in a marriage partner. As in the previous decades, women still valued good financial prospects in a mate roughly twice as much as men did.8 Nor did these gender differences diminish in the 1990s or the 2000s, or in published studies through the year 2015.9
The premium that women place on economic resources has been revealed in many contexts. The psychologist Douglas Kenrick and his colleagues devised a clever method for revealing how much people value different attributes in a marriage partner. They asked men and women to indicate the “minimum percentiles” of each characteristic that they would find acceptable.10 American college women indicated that their minimum acceptable percentile for a husband on earning capacity was the seventieth percentile—that is, they preferred a man who earned more than 70 percent of all other men—whereas men’s minimum acceptable percentile for a wife’s earning capacity was only the fortieth percentile. In research conducted over the past decade, Norman Li has consistently found that women see resources in a mate as a “necessity” rather than a “luxury.”
Personal ads in newspapers, in magazines, and on online dating sites confirm that women who are actually in the marriage market desire financial resources. A study of 1,111 personal ads found that female advertisers seek financial resources roughly eleven times as often as male advertisers do.11 In short, sex differences in a preference for resources are not limited to college students and are not bound by the method of inquiry.
Nor are these female preferences restricted to the United States, or to Western societies, or to capitalist countries. The international study on choosing a mate that I conducted with my colleagues documented the universality of women’s preferences. We investigated populations in thirty-seven cultures on six continents and five islands that varied on many demographic and cultural characteristics. The participants came from nations that practice polygyny, such as Nigeria and Zambia, as well as from nations that are more monogamous, such as Spain and Canada. The countries included those in which living together is as common as marriage, such as Sweden and Finland, as well as countries in which living together without marriage is frowned upon, such as Bulgaria and Greece. In all, the study sampled 10,047 individuals.12
Male and female participants in the study rated the importance of eighteen characteristics in a potential mate or marriage partner, on a scale from “unimportant” to “indispensable.” Women across all continents, all economic systems (including socialism and communism), all ethnic groups, all religious groups, and all systems of mating (from intense polygyny to presumptive monogamy) placed more value than men did on good financial prospects. Overall, women valued financial resources about 100 percent more than men did, or roughly twice as much. There were some cultural variations. Women from Nigeria, Zambia, India, Indonesia, Iran, Japan, Taiwan, Colombia, and Venezuela valued good financial prospects a bit more than women from South Africa’s Zulu communities, the Netherlands, and Finland. In Japan, for example, women valued good financial prospects roughly 150 percent more than men did, whereas women from the Netherlands deemed financial prospects only 36 percent more important than their male counterparts did—less than women from any other country. Nonetheless, the sex difference remained invariant—women worldwide desired financial resources in a marriage partner more than men. These findings provided the first extensive cross-cultural evidence supporting the evolutionary basis for the psychology of human mating. They have become established as among the most robustly documented gender differences in the entire field of psychology.13
Because ancestral women faced the tremendous burdens of internal fertilization, a nine-month gestation, and lactation, they would have benefited tremendously by selecting mates who possessed resources. These preferences helped our ancestral mothers solve the adaptive problems of survival and reproduction for themselves and their children.
Social Status
An examination of traditional hunter-gatherer societies, which are our closest guide to what ancestral conditions were probably like, suggests that ancestral men had clearly defined status hierarchies. In traditional societies today, resources flow freely to those at the top and trickle down slowly to those at the bottom.14 Traditional tribes such as the Tiwi (an aboriginal group residing on two small islands off the coast of northern Australia), the Yanomamö of Venezuela, the Ache of Paraguay, and the !Kung tribe of Botswana are replete with people described as “head men” and “big men” who wield great power and enjoy the resource privileges of prestige. An ancestral man’s social status provided a powerful cue to his possession of resources.
Henry Kissinger once remarked that power is a potent aphrodisiac. Women desire men who command a high position in society because social status is a universal cue to the control of resources. Along with status come better food, more abundant territory, and superior health care. Greater social status bestows on children social opportunities missed by the children of lower-ranked males. Male children in families of higher social status worldwide typically have access to more mates and better-quality mates. In one study of 186 societies ranging from the Mbuti Pygmies of Africa to the Aleut of Alaska, high-status men invariably had greater wealth and more wives than lower-status men, and their children were better nourished.15
Women in the United States express clear preferences for potential mates who have high social status or a high-status profession, qualities that are viewed as only slightly less important than good financial prospects.16 In the 1990s, using a rating scale from “irrelevant” or “unimportant” to “indispensable,” my colleagues and I asked participants from Massachusetts, Michigan, Texas, and California to rate the importance of a potential mate’s social status; women rated it as between important and indispensable, whereas men rated it as merely desirable but not very important.17 In a study of 5,000 college students, women listed status, prestige, rank, position, power, standing, station, and high place as important considerably more frequently than men did.18
David Schmitt and I conducted a study of casual and committed mating to discover which characteristics people especially value in potential spouses, as contrasted with potential sex partners.19 Several hundred individuals rated sixty-seven characteristics for their desirability or undesirability in the short or long term. Women judged the likelihood of success in a profession and the possession of a promising career to be highly desirable in a spouse. Significantly, they saw these cues to future status as more desirable in potential spouses than in casual sex partners.
American women also place great value on education and professional degrees in mates—characteristics that are strongly linked with social status. Women rate lack of education as highly undesirable in a potential husband. The cliché that women prefer to marry doctors, lawyers, professors, successful entrepreneurs, and other professionals seems to correspond with reality. Women shun men who are easily dominated by other men or who fail to command the respect of the group.
Women’s desire for status shows up in everyday life. A colleague overheard a conversation among four women at a restaurant. They were all complaining that there were no eligible men around. Yet these women were surrounded by male waiters, none of whom was wearing a wedding ring. Waiters, who do not have a high-status occupation, were apparently not even considered by these women. What the women really meant was not that there were no eligible men, but that there were no eligible men of acceptable social status.
Women on the mating market look for “eligible” men. The word eligible is a euphemism for “not having his resources already committed elsewhere.” The frequency with which the word appears in the combination “eligible bachelor” reveals the mating desires of women. When women append an adverb to this phrase, it becomes “most eligible bachelor,” referring not to the man’s eligibility but rather to his social status and the magnitude of his resources. It is code for the highest-status, most resource-laden unattached man around. Most homeless and jobless men are eligible, in the sense that they are available as mates, but most women are not interested in them.
The importance that women grant to social status in mates is not limited to the United States or even to capitalist countries. In the vast majority of the thirty-seven cultures included in the international study on choosing a mate, women valued social status more than men in a prospective mate—in both communist and socialist countries, among both Croatians and Chinese, among both Christians and Muslims, in both the tropics and the northern climes.20 For example, women valued status 63 percent more than men in Taiwan, 30 percent more in Zambia, 38 percent more in Germany, and 40 percent more in Brazil. Women see social status more as a “necessity” than as a “luxury” when it comes to long-term mating.21
Because hierarchies are universal features among human groups and resources flow to those who rise in the hierarchy, women solve the adaptive problem of acquiring resources in part by preferring men who are high in status. Social status gives a woman a strong indicator of the ability of a man to invest in her and her children. The scientific evidence across many cultures supports the evolutionary prediction that women are attuned to this cue to the acquisition of resources. Women worldwide prefer to marry up. Those women in our evolutionary past who failed to marry up tended to be less able to provide for themselves and their children.
Age
The age of a man also provides an important cue to his access to resources. Just as young male baboons must mature before they can enter the upper ranks in the baboon social hierarchy, human male adolescents and young men rarely command the respect, status, or position of more mature, older men. This pattern reaches an extreme among the Tiwi tribe, a gerontocracy in which the very old men wield most of the power, have most of the prestige, and control the mating system through complex networks of alliances. Even in American culture, status and wealth tend to accumulate with increasing age.
In all thirty-seven cultures in the international study on choosing a mate, women preferred men who were older than they were.22 Averaged over all cultures, women preferred men who were roughly three and a half years older. The smallest preferred age difference was seen in French Canadian women, who sought husbands who were not quite two years older, and the largest was found among Iranian women, who sought husbands who were more than five years older. The worldwide average age difference between actual brides and grooms is three years, suggesting that women’s marriage decisions often match their mating preferences.
To understand why women value older mates, we must examine what changes with age. One of the most consistent changes is access to resources. In contemporary Western societies, income generally increases with age.23 Thirty-year-old American men, for example, make more money than men who are twenty, and men who are forty make more than thirty-year-olds. These trends are not limited to the Western world. Among traditional nonmodernized societies, older men have more social status. Among the Tiwi tribe, men are typically at least thirty years of age before they acquire enough social status to acquire a first wife.24 Rarely does a Tiwi man under the age of forty attain enough status to acquire more than one wife. Older age, resources, and status are coupled across cultures.
In traditional societies, part of this linkage may be related to physical strength and hunting prowess. Physical strength increases in men as they get older, peaking in their late twenties and early thirties. Anthropologists find that hunting ability peaks when a man is in his thirties, at which point his slight decline in physical prowess is more than compensated for by his increased knowledge, patience, skill, and wisdom.25 Women’s preference for older men may stem from our hunter-gatherer ancestors, for whom the resources derived from hunting were critical to survival and reproduction.
Women may prefer older men for reasons other than tangible resources. Older men are likely to be more mature, more stable, and more reliable in their provisioning. Within the United States, for example, men become somewhat more emotionally stable, more conscientious, and more dependable as they grow older, at least up through the age of thirty.26 In a study of women’s mate preferences, one woman noted that “older men [are] better looking because you [can] talk to them about serious concerns; younger men [are] silly and not very serious about life.”27 The status potential of men becomes clearer with increasing age. Women who prefer older men are in a better position to gauge how high they are likely to rise.
Twenty-year-old women in all thirty-seven cultures in the international study typically preferred to marry men only a few years older, not substantially older, in spite of the fact that men’s financial resources generally do not peak until their forties or fifties. One reason young women are not drawn to substantially older men may be that older men have a higher risk of dying and hence are less likely to be around to continue contributing to the provisioning and protection of children. The potential incompatibility created by a large age discrepancy may lead to strife, thus increasing the odds of divorce. Moreover, men’s sperm quality tends to degrade somewhat with advanced age, which can lead to more birth defects. For these reasons, young women may be drawn more to men a few years older who have considerable promise than to substantially older men who already have attained a higher position but have a less certain future and possibly poorer sperm quality.
Not all women, of course, select older men. Some choose younger men. A study of a small Chinese village found that women who were seventeen or eighteen sometimes married “men” who were only fourteen or fifteen. The conditions in which this occurred, however, were highly circumscribed in that all the “men” were already wealthy, came from a high-status family, and had secure expectations through inheritance.28 Apparently the preference for slightly older men can be overridden when the man possesses other powerful cues to status and resources and when his resource expectations are guaranteed.
Other exceptions occur when women mate with substantially younger men. Many of these cases occur not because of strong preferences by women for younger men but rather because both older women and younger men lack bargaining power on the mating market. Older women often cannot secure the attentions of high-status men and so must settle for younger men, who themselves have not acquired much status or value as mates. Among the Tiwi, for example, a young man’s first wife is typically an older woman—sometimes older by decades—because older women are all he is able to secure with his relatively low status.
Still other exceptions occur among women who already have high status and plentiful resources of their own and then take up with much younger men. Mariah Carey, Madonna, and Cher are striking celebrity examples. They became involved with men who were years or even decades younger. But these cases are relatively rare because most women with resources prefer to mate with men at least as rich in resources as they are, and preferably more so.29 Women may have casual sex with the proverbial “pool boy” or hook up through an online dating app with a younger man, but typically they seek an older man when they decide to settle down for a committed long-term mateship.
All these cues—economic resources, social status, and older age—add up to one thing: the ability of a man to acquire and control resources that women can use for themselves and for their children. A long history of evolution by selection has fashioned the way in which women look at men as success objects. But the possession of resources is not enough. Women also need men who possess traits that are likely to lead to the sustained acquisition of resources over time.
In cultures where people marry young, often the economic capacity of a man cannot be evaluated directly but must be inferred from observable cues. Indeed, in hunter-gatherer groups that lack a cash economy, the target of selection cannot be financial resources per se. Among the Tiwi tribe, for example, young men are scrutinized carefully by both women and older men to evaluate which ones are rising stars, destined to acquire status and resources, and which are likely to remain in the slow lane, based in part on their personality. The young men are evaluated for their promise, the key signs being good hunting skills, good fighting skills, and especially a strong proclivity to ascend the hierarchy of tribal power and influence. Women in all cultures, past and present, can select men for their apparent ability to accrue future resources, based on certain personality characteristics. And women who value the personality characteristics likely to lead to status and sustained resource acquisition are far better off than women who ignore these vital characterological cues.
Ambition and Industriousness
Which tactics do people use to elevate their position in status hierarchies? My lab discovered twenty-six distinct tactics, including deception, social networking, sexual favors, education, and industriousness. The industriousness tactic included actions such as putting in extra time and effort at work, managing time efficiently, prioritizing goals, and working hard to impress others. Among all the tactics, industriousness proved to be the best predictor of past and anticipated income and promotions. Those who worked hard achieved higher levels of education and higher annual salaries, and they anticipated greater salaries and promotions than those who failed to work hard—findings as solid in Norway as in the United States.30 Industrious and ambitious men secure a higher occupational status than lazy, unmotivated men do.31
American women far more often than men desire mates who enjoy their work, show career orientation, demonstrate industriousness, and display ambition.32 The 852 single American women and 100 married American women in the thirty-seven-culture study unanimously rated ambition and industriousness as important or indispensable. Women regard men who lack ambition as extremely undesirable, whereas men view the lack of ambition in a wife as neither desirable nor undesirable. Women are likely to discontinue a long-term relationship with a man if he loses his job, lacks career goals, or shows a lazy streak.33
Women in the overwhelming majority of cultures similarly value ambition and industry more than men do, typically rating it as between important and indispensable. In our study, for example, Taiwanese women rated ambition and industriousness as 26 percent more important than men did, women from Bulgaria rated it as 29 percent more important, and women from Brazil rated it as 30 percent more important.
The cross-cultural and cross-generational evidence supports the key evolutionary expectation that women have evolved a preference for men who show signs of the ability to acquire resources and a disdain for men who lack ambition. Hard work and ambition, however, are not the only available cues to potential resources. Two others, dependability and stability, provide critical information about how steady or erratic these resources will be.
Dependability and Stability
Among the eighteen characteristics rated in the thirty-seven-culture study, the second and third most highly valued characteristics were a dependable character and emotional stability or maturity. In twenty-one out of thirty-seven cultures, men and women had the same preference for dependability in a partner. Of the sixteen cultures where there was a gender difference, women in fifteen of the cultures valued dependability more than men did. Averaged across all thirty-seven cultures, women rated dependable character 2.69 (where a 3.00 signifies indispensable); men rated it nearly as important, with an average of 2.50. In the case of emotional stability or maturity, the sexes differed more. Women in twenty-three cultures valued this quality significantly more than men did; in the remaining fourteen cultures, men and women valued emotional stability equally. Averaging across all cultures, women gave this quality a 2.68, whereas men gave it a 2.47.
These characteristics may possess such a great value worldwide because they are reliable signals that resources will be provided consistently over time. Undependable people, in contrast, provide erratically and inflict heavy costs on their mates. In a study of newlywed couples, my lab found that emotionally unstable men were especially costly to women. They tended to be self-centered, to monopolize shared resources, and to be possessive, monopolizing much of the time of their wives. These men showed higher-than-average sexual jealousy, becoming enraged when their wives even talked with someone else, as well as dependency: they would insist that their mates provide for all of their needs. With a tendency to being abusive, both verbally and physically, they also displayed inconsiderateness, such as by failing to show up on time. Emotionally unstable men were also moodier than their more stable counterparts, sometimes crying after minor setbacks. Suggesting a further diversion of their time and resources was their tendency to have more affairs than average.34 All of these costs indicate that emotionally unstable mates will absorb their partner’s time and resources, divert their own time and resources elsewhere, and fail to channel resources consistently over time. Dependability and stability are personal qualities that signal increased likelihood that a woman’s resources will not be drained by the man.
The unpredictable aspects of emotionally unstable men inflict additional costs by impeding solutions to critical adaptive problems. The erratic supply of resources can wreak havoc with accomplishing the goals required for survival and reproduction. Meat that is suddenly not available because an undependable mate decided at the last minute to take a nap rather than go on the hunt is a resource that was counted on but not delivered. Its absence creates problems for nourishment and sustenance. Resources prove most beneficial when they are predictable. Erratically provided resources may even go to waste when the needs they were intended to meet are met through other, more costly means. Resources that are supplied predictably can be more efficiently allocated to the many adaptive hurdles that must be overcome in everyday life.
Women place a premium on dependability and emotional stability to avoid incurring these costs and to reap the benefits that a mate can provide to them consistently over time. In ancestral times, women who chose stable, dependable men had a greater likelihood of ensuring the man’s ability to acquire and maintain resources for use by them and their children. Women who made these wise choices avoided many of the costs inflicted by undependable and unstable men.
Intelligence
Dependability, emotional stability, industriousness, and ambition are not the only personal qualities that signal the acquisition and steadiness of resources. The ephemeral quality of intelligence provides another important cue. No one knows for sure what intelligence tests measure, but there is clear evidence of what high scorers can do. Intelligence is a good predictor of the possession of economic resources within the United States.35 People who test high go to better schools, get more years of education, and ultimately get higher-paying jobs. Even within particular professions, such as construction and carpentry, intelligence predicts who will advance more rapidly to positions of power and command higher incomes. In tribal societies, the head men or leaders are almost invariably among the more intelligent members of the group.36
If intelligence has been a reliable predictor of economic resources over human evolutionary history, then women could have evolved a preference for this quality in a potential marriage partner. The international study on choosing a mate found that women rated education and intelligence fifth out of eighteen desirable characteristics. Ranked in a smaller list of thirteen desirable characteristics, intelligence emerged in second place worldwide. Women valued intelligence more than men in ten out of the thirty-seven cultures. Estonian women, for example, ranked intelligence third out of thirteen desired characteristics, whereas Estonian men ranked it fifth. Norwegian women valued it second, whereas Norwegian men ranked it fourth. In the remaining twenty-seven cultures, however, both sexes placed the same high premium on intelligence.
The quality of intelligence signals many potential benefits. These are likely to include good parenting skills, capacity for cultural knowledge, and adeptness at parenting.37 In addition, intelligence is linked with oral fluency, ability to influence other members of a group, prescience in forecasting danger, and judgment in applying health remedies. Beyond these specific qualities, intelligence conveys the ability to solve problems. Some have speculated that intelligence is a marker of “good genes” that can be passed on to sons and daughters.38 Women who select more intelligent mates are more likely to become the recipients of all of these critical benefits.
To identify some of the actions that intelligent people perform, my lab asked 140 men and women to think of the most intelligent people they knew and to describe five actions that reflected their intelligence. Their descriptions of these five types of actions imply the benefits that may flow to someone fortunate enough to choose an intelligent person as a mate: (1) intelligent people tend to have a wide perspective and to see an issue from multiple points of view, suggesting better judgment and decision making; (2) they communicate messages well to other people and are sensitive to signs of how others are feeling, suggesting good social skills; (3) they know where to go to solve problems, implying good judgment; (4) intelligent people manage money well, suggesting that resources will not be lost or squandered; and (5) they make few mistakes in accomplishing tasks they have never before attempted, suggesting an efficiency in problem solving and allocating time. By selecting an intelligent mate, women increase their chances of receiving all these benefits.
Contrast these benefits with the costs imposed by less intelligent people. Their behavior includes failing to pick up subtle hints from others, missing a joke that everyone else gets, and saying the wrong thing at the wrong time, all of which suggest a lack of social adeptness. Less intelligent people repeat mistakes, suggesting that they have less ability to learn from experience. They fail to follow simple verbal instructions, fail to grasp explanations, and persist in arguing when they are obviously wrong. This behavior implies that unintelligent mates are poor problem solvers, unreliable workers, and social liabilities.
Ancestral women who preferred intelligent mates would have raised their odds of securing social, material, and economic resources for themselves and for their children. Since intelligence is moderately heritable, these favorable qualities would have been passed on genetically to their sons and daughters, providing an added genetic benefit. Modern women and most men across all cultures hold these preferences.
Compatibility
Successful long-term mating requires a sustained cooperative alliance with another person for mutually beneficial goals. Relationships riddled with conflict impede the attainment of these goals. Compatibility between mates entails a complex mesh between two different kinds of characteristics. One kind involves complementary traits, or a mate’s possession of resources and skills that differ from one’s own, in a kind of division of labor between the sexes. Both partners can benefit from specialization and division.
The other kinds of traits crucial to compatibility with a mate, however, are those that are most likely to mesh cooperatively with one’s own particular personal characteristics and thus are most similar to one’s own. Discrepancies between partners in their political orientations, religious views, moral values, hobbies and interests, and even personalities can produce strife and conflict. The psychologist Zick Rubin and his colleagues studied 202 dating couples over several years to see which ones stayed together and which broke up.39 They found that mismatched couples tended to break up more readily than their matched counterparts. The 103 couples who broke up had more dissimilar values on sex roles, sexual attitudes, romanticism, and religious beliefs than did the 99 couples who stayed together.
One solution to the problem of compatibility is to search for similarity in a mate. Both in the United States and worldwide, men and women who are similar to each other on a wide variety of characteristics tend to get married. The tendency for like people to mate shows up most obviously in the areas of values, intelligence, and group membership.40 People seek mates with similar political and social values, such as their views on abortion and capital punishment. People also desire mates who are similar in race, ethnicity, and religion. Couples desire and marry mates of similar intelligence. In addition, similarity matters in personality characteristics such as extraversion, agreeableness, and conscientiousness. People like mates who share their inclination toward parties if they are extraverted and toward quiet evenings at home if they are introverted. People who are characteristically open to experience prefer mates who share their interest in wines, art, literature, and the culinary delights of fine foods. Conscientious people prefer mates who share their interest in paying bills on time and saving for the future. Less conscientious people prefer mates who share their interest in living for the moment.
The similarity within compatible couples is in part a by-product of the fact that people tend to marry others who are in close proximity, and those who are nearby tend to be similar to oneself. Similarity of intelligence in modern marriages, for example, may be an incidental outcome of the fact that people of similar intelligence tend to go to the same educational institutions. The incidental outcome explanation, however, cannot account for the widespread preference that people express for mates who are similar.41 In a study conducted on dating couples in Cambridge, Massachusetts, my lab measured the personalities and intelligence levels of 108 individuals who were involved in a dating relationship. Separately, the couples completed a questionnaire that asked for their preferences in an ideal mate on the same qualities. The study found that women preferred mates who were similar to themselves in many respects, including boldness, dominance, and activeness; warmth, agreeableness, and kindness; responsibility, conscientiousness, and industriousness; and especially intelligence, perceptiveness, and creativity.
The search for a similar mate provides an elegant solution to the adaptive problem of creating compatibility within the couple so that their interests are maximally aligned in the pursuit of mutual goals. Consider a woman who is an extravert and loves wild parties and who is married to an introvert who prefers quiet evenings at home. Although they may decide to go their separate ways evening after evening, the mismatch causes strife. Couples in which both members are introverted or both are extraverts do not butt heads about mutually pursued activities. The marriage of a Democrat and a Republican or a gun control advocate and a gun rights proponent can make for interesting discussions, but the ensuing conflict wastes valuable energy.
Perhaps more important, matched couples maximize the smooth coordination of their efforts when pursuing mutual goals such as child rearing, maintaining kin alliances, and social networking. A couple at odds over how to rear their child waste valuable energy and also confuse the child, who receives contradictory messages. The search for similarity prevents couples from incurring these costs.
People also seek similarity in overall mate value. Because personality characteristics such as agreeableness, conscientiousness, and intelligence are all highly desirable on the mating market, those who possess more of them can command more of them in a mate.42 Those who lack these valuable personal assets can command less and so often limit their search to those with assets that are similar to their own. By seeking similarity, individuals avoid wasting time and energy trying to attract people who are out of their reach. Consider this example. A female colleague complained that all the men she was attracted to were not interested in her, yet she was being pursued constantly by men she was not really interested in. Her friend told her: “You are an 8, going after 10s, but being sought by 6s.”43 This single observation proved more valuable to her on the mating market than three years of therapy. She adjusted her mating strategy accordingly.
Those who compete for a mate who exceeds their own mate value risk abandonment by the partner whose mating options are more expansive. Partners discrepant in mate value tend to break up because the more desirable partner can strike a better bargain elsewhere.44
The search for similarity thus solves several adaptive problems simultaneously: it maximizes the value one can command on the mating market; leads to the coordination of efforts; reduces conflict within the couple; avoids the costs of mutually incompatible goals; and reduces the risk of later abandonment or breakup.
Size, Strength, and V-Shaped Torso
When the great basketball player Magic Johnson revealed that he had slept with thousands of women, he inadvertently revealed women’s preference for mates who display physical and athletic prowess. The numbers may be shocking, but the preference is not. Physical characteristics, such as athleticism, size, and strength, convey important information that women use in making a mating decision.
The importance of physical characteristics in the female choice of a mate is prevalent throughout the animal world. In the species called the gladiator frog, males are responsible for creating nests and defending the eggs.45 In the majority of courtships, a stationary male is deliberately bumped by a female who is considering him. She strikes him with great force, sometimes enough to rock him back or even scare him away. If the male moves too much or bolts from the nest, the female hastily leaves to examine alternative mates. Most females mate with males who move minimally when bumped. Only rarely does a female reject a male who remains firmly planted after being bumped. Bumping helps a female frog to decide how successful the male will be at defending her clutch. The bump test reveals the male’s physical ability to perform the function of protection.
Women sometimes face physical domination by men who are larger and stronger than they are, which can lead to injury and sexual aggression and prevent them from exercising choice. Such domination undoubtedly occurred regularly during ancestral times. Indeed, studies of many nonhuman primate groups reveal that male physical and sexual domination of females has been a recurrent part of our primate heritage. The primatologist Barbara Smuts lived among baboons in the savannah plains of Africa while studying their mating patterns. She found that females form enduring “special friendships” with males who offer physical protection to them and their infants. In return, these females grant their “friends” preferential sexual access during times of estrus.
Analogously, one benefit to women of committed mating is the physical protection a man can offer. A man’s size, strength, and physical prowess are cues to solutions to the problem of protection. My lab and others found that women judge short men to be undesirable as long-term mates.46 In contrast, they find it very desirable for a potential mate to be tall, physically strong, and athletic. Tall men are consistently seen as more desirable dates and mates than men who are short or of average height.47 Two studies of personal ads revealed that, among women who mention height, 80 percent want a man who is six feet or taller. Ads placed by taller men receive more responses from women than those placed by shorter men, which may explain why men tend to “round up” by a couple of inches when describing their height to women on online dating sites. Tall men date more often than short men and have a larger pool of potential mates. Women solve the problem of protection from aggressive men at least in part by preferring a mate who has the size, strength, and physical prowess to protect them.
In addition to height, women are especially attracted to athletic men with a V-shaped torso, that is broader shoulders relative to hips.48 Interestingly, these female preferences may have exerted sexual selection pressure on men, since modern men currently show upper body strength that is roughly twice that of women. It is one of the most sexually dimorphic attributes of the human body.
Tall men tend to have a higher status in nearly all cultures. “Big men” in hunter-gatherer societies—men high in status—are physically big men as well.49 In Western cultures, tall men make more money, advance in their professions more rapidly, and receive more and earlier promotions. Few American presidents have been less than six feet tall. Politicians are keenly aware of voters’ preference. During the televised presidential debate in 1988, George H. W. Bush made a point of standing very close to his shorter competitor, Michael Dukakis, in a strategy of highlighting their disparity in size. As the evolutionary psychologist Bruce Ellis notes:
Height constitutes a reliable cue to dominance in social interactions . . . shorter policemen are likely to be assaulted more than taller policemen . . . suggesting that the latter command more fear and respect from adversaries . . . taller men are more sought after in women’s personal advertisements, receive more responses to their own personal advertisements, and tend to have prettier girlfriends than do shorter men.50
This preference for taller men is not limited to Western cultures. For men of the Mehinaku tribe of the Brazilian Amazon, the anthropologist Thomas Gregor notes, size differences have acutely important effects in the wrestling arena:
A heavily muscled, imposingly built man is likely to accumulate many girlfriends, while a small man, deprecatingly referred to as a peritsi, fares badly. The mere fact of height creates a measurable advantage. . . . A powerful wrestler, say the villagers, is frightening . . . he commands fear and respect. To the women, he is “beautiful” (awitsiri), in demand as a paramour and husband. Triumphant in politics as well as in love, the champion wrestler embodies the highest qualities of manliness. Not so fortunate the vanquished! A chronic loser, no matter what his virtues, is regarded as a fool. As he wrestles, the men shout mock advice. . . . The women are less audible as they watch the matches from their doorways, but they too have their sarcastic jokes. None of them is proud of having a loser as a husband or lover.51
The presence of aggressive men who tried to dominate women physically and to circumvent their sexual choices may have been an important influence on women’s mate selection in ancestral times. Barbara Smuts argues that, consequently, during human evolutionary history physical protection from other men was one of the most important things a man could offer a woman. Given the alarming incidence of sexual coercion and rape in many cultures, a mate’s protection value may well remain relevant to mate selection in modern environments. Many women simply do not feel safe on the streets, and a strong, tall, athletic mate acts as a deterrent to other sexually aggressive men.
Good Health, Symmetry, and Masculinity
It may come as no surprise that women and men worldwide prefer mates who are healthy.52 In the thirty-seven-culture study, women judged good health to be anywhere from important to indispensable in a marriage partner. In another study on American women, poor physical conditions, ranging from bad grooming habits to having a sexually transmitted infection (STI), were regarded as extremely undesirable characteristics in a mate. The biologists Clelland Ford and Frank Beach found that signs of ill health, such as open sores, lesions, and unusual pallor, are universally regarded as unattractive.53
In humans, good health may be signaled by behavior as well as by physical appearance. A lively mood, high energy level, and sprightly gait, for example, may be attractive precisely because they are calorically costly and can be displayed only by people brimming with good health.
The tremendous importance we place on good health is not unique to our species. Some animals display large, loud, and gaudy traits that are costly and yet signal great health and vitality. Consider the bright, flamboyant, ostentatious plumage of the peacock. It is as if the peacock is saying: “Look at me; I’m so fit that I can carry these large, cumbersome feathers, and yet still I’m thriving.” The mystery of the peacock’s tail, which seems so contrary to utilitarian survival, is finally on the verge of being solved. The biologists William D. Hamilton and Marlena Zuk proposed that the brilliant plumage serves as a signal that the peacock carries a light load of parasites, since peacocks who carry more than the average number of parasites have duller plumage.54 The burdensome plumage provides a cue to health and robustness. Peahens prefer the brilliant plumage because it provides clues to the male’s health.
Women are especially attracted to men who show two observable markers of good health—symmetrical features and masculinity. Bodies are supposed to be bilaterally symmetric, so deviations in symmetry represent errors a body made in constructing itself. These superficial errors may signal other errors made in constructing important systems, such as the immune system. Errors have two sources—genetic mutations and environmental stresses such as injuries or disease during development. More symmetrical men tend to be healthier and to experience fewer illnesses such as respiratory diseases, and women find them more attractive than their more lopsided peers.55
Masculine features in men provide another set of health cues. These features include longer and broader lower jaws, stronger brow ridges, deeper voices, and the classic male V-shaped torso. Masculine qualities are primarily the product of testosterone production during adolescence when a male’s facial, body, and vocal qualities are forming. The problem is that too much testosterone can be bad for men, compromising their immune system and leading to shorter lives. So why do some men develop such masculine features? The theory is that only very healthy men, those with strong immune systems, can afford to produce a lot of testosterone during adolescence. Men with weaker immune systems cut back on testosterone production (not consciously, of course) to prevent compromising their already tenuous health. According to this theory, masculine features are honest signals of good health. And indeed, women find masculine features to be somewhat attractive in long-term mating, although they find these features even more attractive when choosing a casual sex partner.
In ancestral times, four bad consequences were likely to follow if a woman selected a mate who was unhealthy or disease-prone. First, she put herself and her family at risk of contracting the disease. Second, her mate was less able to perform essential functions and provide crucial benefits to her and her children, such as food, protection, health care, and child rearing. Third, her mate was at increased risk of dying, prematurely cutting off the flow of resources and forcing her to incur the costs of searching for a new mate and courting all over again. And fourth, if health is partly heritable, she would risk passing on genes for poor health to her children. A preference for healthy mates solves the problem of mate survival and ensures that resources are likely to be delivered over the long run.
Love, Kindness, and Commitment
A man’s possession of assets such as health, status, resources, intelligence, and emotional stability, however, does not guarantee his willingness to commit them to a particular woman. Some men show a tremendous reluctance to marry or commit. Some prefer playing the field of singledom and seek a series of casual sex partners. Some popular online dating apps, such as Tinder, facilitate this short-term strategy. Women sometimes derogate men for this hesitancy, calling them “commitment dodgers,” “commitment phobics,” “paranoid about commitment,” and “fearful of the M word.”56 And women’s negative reaction to these proclivities makes sense given the large asymmetries in the costs of sex. Because women historically incurred large costs and heavy investment as a result of sex, pregnancy, and childbirth, it often has been reproductively advantageous for them to seek some level of commitment from men with whom they have sex.
The weight that women attach to commitment is revealed in the following true story (the names are changed). Mark and Susan had been going out with each other for two years and had been living together for six months. He was a well-off forty-two-year-old professional, she a medical student of twenty-eight. Susan pressed for a decision about marriage—they were in love, and she wanted to have children within a few years. But Mark balked. He had been married before, and divorced. If he ever married again, he wanted to be absolutely sure it would be permanent. As Susan continued to press for a decision, Mark raised the possibility of a prenuptial agreement. She resisted, feeling that this violated the spirit of marriage. Finally, they agreed that by a date four months in the future he would have decided one way or the other. The date came and went, and still Mark could not make a decision. Susan told him that she was leaving him, moved out, and started dating another man. Mark panicked. He called her up and begged her to come back, saying that he had changed his mind and would marry her. He promised a new car. He promised that there would be no prenuptial agreement. But it was too late. Mark’s failure to commit was too strong a negative signal to Susan. It dealt the final blow to their relationship. She was gone forever.
Women past and present face the adaptive problem of choosing men who not only have the necessary resources but also show a willingness to commit those resources specifically to them. This problem may be more difficult than it seems at first. Although resources can often be directly observed, commitment cannot. Instead, gauging commitment requires looking for probabilistic cues. Love is one of the most important cues to commitment.
Feelings and acts of love are not recent products of particular Western views, contrary to some conventional beliefs in the social sciences. Love is universal. Thoughts, emotions, and actions of love are experienced by people in all cultures worldwide—from the Zulu in the southern tip of Africa to the Inuit in the north of Alaska. In a survey of 168 diverse cultures from around the world, the anthropologist William Jankowiak found strong evidence for the presence of romantic love in nearly 90 percent of them. For the remaining 10 percent, the anthropological records were too sketchy to definitely verify the presence of love. When the sociologist Sue Sprecher and her colleagues interviewed 1,667 men and women in Russia, Japan, and the United States, they found that 61 percent of the Russian men and 73 percent of the Russian women were currently in love. Comparable figures for the Japanese were 41 percent of the men and 63 percent of the women. Among Americans, 53 percent of the men and 63 percent of the women acknowledged being in love. Clearly, love is not a phenomenon limited to Western cultures.57
To identify precisely what love is and how it is linked to commitment, my lab initiated a study of acts of love.58 First, we asked fifty women and fifty men from the University of California, Berkeley, and the University of Michigan to think of people they knew who were currently in love and to describe actions performed by those people that reflected or exemplified their love. A different group of college men and women evaluated each of the nominated 115 acts for how typical it was of love. Acts of commitment topped the women’s and men’s lists, being viewed as most central to love. Such acts included giving up romantic relations with others, talking of marriage, and expressing a desire to have children with the person. When performed by a man, these acts of love signaled the intention to commit resources to one woman.
Commitment has many facets. One major component of commitment is fidelity, exemplified by the act of remaining faithful to a partner when apart. Fidelity signals the exclusive commitment of sexual resources to a single partner. Another aspect of commitment is the channeling of resources to the loved one, such as buying an expensive gift or ring. These acts signal a serious intention to commit economic resources to a long-term relationship. Emotional support is yet another facet of commitment, revealed by behavior such as being available in times of trouble and listening to the partner’s problems. Commitment entails a channeling of time, energy, and effort to the partner’s needs at the expense of fulfilling one’s own personal goals. Acts of reproduction, such as planning to have children, also represent a direct commitment to one’s partner’s genes. All these acts of love signal the commitment of sexual, economic, emotional, and genetic resources to one person.
Since love is a worldwide phenomenon, and since a primary function of acts of love is to signal commitment of reproductively relevant resources, women should place a premium on love in the process of choosing a mate. To find out if they do, Sue Sprecher and her colleagues asked American, Russian, and Japanese students whether they would marry someone who had all the qualities they desired in a mate if they were not in love with that person.59 Fully 89 percent of American women and 82 percent of Japanese women said that they would still require love for marriage, even if all other important qualities were present. Among Russians, only 59 percent of women would not marry someone with whom they were not in love, no matter how many desirable qualities that person had. Although a clear majority of Russian women required love, the lower threshold may reflect the tremendous difficulty Russian women have in finding a mate because of the severe shortage of men in their country, especially men capable of investing resources. These variations reveal the effects of cultural context on mating. Nonetheless, the majority of women in all three cultures saw love as an indispensable ingredient in marriage.
Direct studies of preferences in a mate confirm the centrality of love. In a study of 162 Texas women college students, out of 100 characteristics examined, the quality of being loving was the most strongly desired in a potential husband.60 The thirty-seven-culture study confirmed the universal importance of love. Among eighteen possible characteristics, mutual attraction or love proved to be the most highly valued in a potential mate by both sexes, being rated a 2.87 by women and 2.81 by men (out of 3.00). Nearly all women and men, from the enclaves of South Africa to the bustling streets of Brazilian cities, gave love the top rating, indicating its indispensability for a committed mateship. Women place a premium on love in order to secure the commitment of men’s economic, emotional, and sexual resources.
Two additional personal characteristics, kindness and sincerity, are critical to securing long-term commitment. In one study of 800 personal advertisements, sincerity was the single most frequently listed characteristic sought by women.61 Another analysis of 1,111 personal advertisements again showed that sincerity was the quality most frequently sought by women—indeed, women advertisers sought sincerity nearly four times as often as men advertisers.62 Sincerity in personal advertisements is a code word for commitment, and women use it to screen out men seeking casual sex without any commitment.
People worldwide depend on kindness not from strangers, but rather from their mates. As shown by the thirty-seven-culture study, women have a strong preference for mates who are kind and understanding. In thirty-two out of the thirty-seven cultures, in fact, the sexes were identical in valuing kindness as one of the three most important qualities out of a possible thirteen in a mate. Only in Japan and Taiwan did men give greater emphasis than women to kindness. And only in Nigeria, Israel, and France did women give greater emphasis than men to kindness. In no culture, however, was kindness in a mate ranked lower than third out of thirteen for either sex. Women desired kindness in a mate especially when it was directed toward them, and less so when it was directed toward other people or other women, supporting the notion that women prize dispositions in men to commit their resources selectively rather than indiscriminately.63
Kindness is an enduring personality characteristic that has many components, but at the core of all of them is the commitment of resources. The trait signals an empathy toward children, a willingness to put a mate’s needs before one’s own, and a willingness to channel energy and effort toward a mate’s goals rather than exclusively and selfishly to one’s own goals.64 Kindness, in other words, signals the ability and willingness of a potential mate to commit energy and resources selflessly to a partner.
A lack of kindness signals selfishness, an inability or unwillingness to commit, and a high likelihood that costly burdens will be inflicted on a spouse. The study of newlyweds, for example, found that women married to unkind men complained that their spouses abused them both verbally and physically by hitting, slapping, or spitting at them. Unkind men tend to be condescending, putting down their wife’s opinions as stupid or inferior. They are selfish, monopolizing shared resources. They are inconsiderate, failing to do any housework. They are neglectful, failing to show up as promised. Finally, they have more extramarital affairs, suggesting that these men are unable or unwilling to commit to a monogamous relationship.65 Unkind men look out for themselves and have trouble committing to anything much beyond that.
Because sex is one of the most valuable reproductive resources women can offer, they have evolved psychological mechanisms that cause them to resist giving it away indiscriminately. Requiring love, sincerity, and kindness is a way of securing a commitment of resources commensurate with the value of the resource that women give to men. Requiring love and kindness helps women to solve the critical adaptive mating problem of securing the commitment of resources from a man that can aid in the survival and reproduction of her offspring.
Deal Breakers
The flip side of what women want is what women do not want—the proverbial deal breakers. Incest avoidance is one of the most important. Reproducing with a genetic relative creates “inbreeding depression,” which results in children with genetic abnormalities such as Down’s syndrome and lower levels of intelligence. Although most people experience the emotion of disgust when contemplating sex with close kin, women are especially repulsed. This gender difference follows from the facts of parental investment—the costs of making a poor sexual decision are typically higher for women than for men. Even the thought of tongue-kissing a sibling or parent typically evokes strong disgust in women.66 Alongside “beats me up,” “will have sex with other people when he is with me,” and “is addicted to drugs,” “is my sibling” is one of the most powerful deal breakers for women.67
Most deal breakers, however, are simply the inverses of the qualities that women desire—lacking resources, drive, ambition, or status; lacking intelligence; being undependable or emotionally unstable; being small, weak, or feminine in appearance; being unhealthy or asymmetrical; being mean or cruel; and lacking love specifically for the woman doing the mate selecting.
Do Women’s Desires Change When They Have Power and Resources?
Many years ago, I offered a different possible explanation for women’s preferences for men with resources, based on the so-called structural powerlessness and sex-role socialization of women.68 According to this view, because women are typically excluded from power and access to resources, which are largely controlled by men, women seek mates who have power, status, and earning capacity. Women try to marry upward in socioeconomic status to gain access to resources. Men do not value economic resources in a mate as much as women do because men already have control over these resources and because women have fewer resources anyway.
The society of Bakweri, from Cameroon in West Africa, casts doubt on this theory by illustrating what happens when women have real power. Bakweri women hold greater personal and economic power because they have more resources and are in scarcer supply than men.69 Women secure resources through their own labors on plantations, but also from casual sex, which is a lucrative source of income. There are roughly 236 men for every 100 women, an imbalance that results from the continual influx of men from other areas of the country to work on the plantations. Because of the extreme imbalance in numbers of the sexes, women have more money than men and more potential mates to choose from. Yet despite this greater latitude, Bakweri women persist in preferring to have a mate with resources. Wives often complain about receiving insufficient support from their husbands. Indeed, lack of sufficient economic provisioning is the most frequently cited divorce complaint of women. Bakweri women change husbands if they find a man who can offer them more money and pay a larger bride price. When women are in a position to fulfill their evolved preference for a man with resources, they do so. Having the dominant control of economic resources does not diminish this key mate preference.
Professionally and economically successful women in the United States also value resources in men. My lab’s newlywed study identified women who were financially successful, measured by their salary and income, and contrasted their preferences in a mate with those of women with lower salaries and income. Many of the financially successful women earned more than $100,000 per year in today’s dollars. These women were well educated, tended to have professional degrees, and had high self-esteem. Perhaps surprisingly, the study showed that successful women place an even greater value than less successful women on mates who have professional degrees, high social status, and greater intelligence, as well as desiring mates who are tall, independent, and self-confident. These women also express an even stronger preference for high-earning men than do women who are less financially successful. In a separate study the psychologists Michael Wiederman and Elizabeth Allgeier found that college women who expected to earn the most after college placed more importance on the financial prospects of a potential husband than did women who expected to earn less. Professionally successful women, such as medical students and law students, also assigned great importance to a mate’s earning capacity.70 Furthermore, men who were low in financial resources and status did not value economic resources in a mate any more than financially successful men did.71
Cross-cultural studies also find that women with their own economic resources value resources in a potential mate more, not less, than women lacking these resources. A study of 1,670 Spanish women found that high-resource women wanted mates with more status and more resources.72 A study of 288 Jordanians found the same thing, as did a study of 127 Serbians and an Internet study of 1,851 English women.73 Taken together, these results not only fail to support the structural powerlessness or sex-role hypothesis but directly contradict it.
Structural powerlessness has an element of truth in that men in many cultures do control resources and sometimes do exclude women from power. But the theory cannot explain several facts: men strive to exclude other men from power at least as much as they do women; the origins of the male motivation to control resources remain unexplained; women have not evolved bigger, stronger bodies to acquire resources directly; and men’s preferences in a mate remain entirely mysterious. Evolutionary psychology accounts for this constellation of findings. Men strive to control resources and to exclude other men from resources to fulfill women’s mating preferences. In human evolutionary history, men who failed to accumulate resources failed to attract mates. Men’s more powerful status and resource acquisition drives are due, at least in part, to the preferences that women have expressed over the past few million years. To paraphrase the evolutionary anthropologist Sarah Hrdy, “Men are one long breeding experiment run by women.”
Sexual Orientation and Mate Preferences
As mentioned in Chapter 1, the origins of same-sex sexual orientation remain largely a mystery. The mate preferences of women who self-identify as lesbian, however, are better known. In 2007, Richard Lippa published the largest study on this topic, reporting the mate preferences of 2,548 lesbian women and comparing them to those of 82,819 heterosexual women.74 He found two clusters of findings. First, many of the mate preferences of the two groups were quite similar. Both valued health, kindness, industriousness, sense of humor, and similar values in a mate. Lesbian women differed from heterosexual women, however, in placing less importance on fondness for children, parenting abilities, and religion. Interestingly, although both groups placed tremendous importance on honesty and intelligence, lesbian women valued these traits even more strongly.
Another study examined individual differences among lesbian women, focusing on differences between those who self-identified as “butch” and as “femme.”75 Butch women tended to be more masculine, dominant, and assertive; femme women tended to be more sensitive, cheerful, and feminine. The femme tended to express a stronger desire to have children and placed more importance on the financial resources of a potential romantic partner. Butch lesbians tended to place less emphasis on the financial resources of a potential partner but experienced greater jealousy over rival competitors who were more financially successful.
Thus, in many ways lesbian women are somewhat similar to heterosexual women in their mate preferences, but differ in a few of the qualities desired. More importantly, there are large individual differences among self-identified lesbians, and these variations caution against sweeping generalizations.
Context-Dependent Shifts in Women’s Desires
In addition to a woman’s personal economic power, several other circumstances cause predictable changes in which men she desires. These include whether other women find a man attractive, whether she is seeking a committed partner or casual sex, and her own mate value.
One of the most successful beer commercials of all time depicts a well-dressed man with a bottle of Dos Equis in his hand. Depending on the version, there are either two or three very attractive women surrounding him. This commercial might appeal to men because it implies that they will enhance their attractiveness to women if they drink this brand of beer. But being surrounded by beautiful women also makes the man more attractive to women. Animal biologists have given this phenomenon the clunky name mate copying. From fish to birds, females use the apparent preferences of other females as critical information about a potential mate’s mate value. Mate copying has also been found in humans in my lab (in a study led by Sarah Hill) and in four other labs. Women find men surrounded by other women especially attractive if those women are themselves physically attractive and if they seem attentive to, and interested in, the man.
Temporal context—whether a woman is seeking a sexual hookup or a committed partner—also influences desire. In long-term mating, women prioritize character traits such as kindness, dependability, and emotional stability, as well as qualities that signal excellent future status and resource potential, such as ambition, industriousness, and education. For casual sex partners, however, these qualities become considerably less important. Instead, women emphasize physical attractiveness, desirability to other women, and higher levels of masculinity—qualities that might be linked with “good genes,” a topic we cover in greater depth in Chapter 4.
Finally, women’s own level of desirability influences their desires. It may not come as a shock that women who are 8’s are generally choosier than women who are 6’s or 5’s. More desirable women have more bargaining power on the mating market, and they can elevate their standards. Women with high mate value in Canada, America, Croatia, Poland, Brazil, and Japan have been found to list a longer set of sought-after traits in their personal ads. They want higher levels of resources, education, and intelligence; higher social status; good parenting skills; good partner skills; and a raft of other traits. What may be less intuitively obvious is that women with high mate value are especially drawn to masculine men compared with their lower-mate-value counterparts. This disparity has been found for vocal masculinity as well as facial masculinity. One speculation for this preference shift pivots on the finding that masculine men tend on average to be less faithful than less masculine men. Perhaps only a woman who is high in mate value herself feels that she can control the wandering eye of an attractive, masculine man by reminding him that he risks losing her.
Effects of Women’s Desires on Actual Mating Behavior
Mate preferences cannot evolve unless they affect actual mating behavior at least some of the time. Of course, people cannot always get what they want. Most must settle for someone less than their ideal mate. A raft of scientific studies demonstrate, however, that women’s desires do influence their actual mating decisions.
One source of evidence comes from personal ads. Which ads placed by men get more “hits,” clicks, or “right swipes” from women? Age is a key predictor. More mature men get more hits than younger men, although women generally set the limit at ten years older than themselves. Men who indicate higher levels of income and education get more hits, a trend that has been replicated in Poland as well as the United States.76
A study of 21,973 men found that those higher in socioeconomic status were more likely to attract wives.77 Poor men are more likely to remain bachelors. Among the Kipsigis of Kenya, men with land resources are more likely to attract wives, and men with a lot of land attract multiple wives.78 American men with resources are more likely to marry physically attractive women. And women worldwide in all cultures across the globe tend, on average, to marry men who are somewhat older than they are.79
Women’s desires in a mate also influence men’s behavior, precisely as predicted from the logic of sexual selection theory. Studies of mate attraction find that men display resources such as cars, houses, gifts, and expensive dinners to attract women. And men derogate their rivals verbally by impugning their status, ambition, physical prowess, and resources. Even in online dating ads, men are more likely than women to exaggerate their income, education level, and height, rounding up by about 10 to 20 percent. In all these ways, women’s mate preferences influence actual mating behavior, both their own and that of the men seeking to attract them.
Women’s Many Preferences
We now have the outlines of an answer to the enigma of what women want. Women are judicious, prudent, and discerning about the men they consent to mate with because they have so many valuable reproductive resources to offer. Those with valuable resources rarely give them away indiscriminately. The costs in reproductive currency of failing to exercise choice were too great for ancestral women, who would have risked beatings, food deprivation, disease, abuse of children, and abandonment. By contrast, the benefits of exercising choice—in nourishment, protection, gene quality, and paternal investment in children—were abundant.
Committed mates may bring with them a treasure trove of resources. Selecting a long-term mate who has the relevant resources is clearly an extraordinarily complex endeavor. For women, it involves at least a dozen distinctive preferences, each corresponding to a resource that helps them solve critical adaptive problems.
That women seek resources in a long-term mate may seem obvious to the casual observer, but until the thirty-seven-culture study, that preference had not been scientifically documented worldwide. Moreover, because men’s resources and resource acquisition skills often cannot be directly discerned, women’s preferences are keyed to other qualities that signal the likely possession, or future acquisition, of resources. Indeed, women may be less influenced by money per se than by qualities that lead to resources, such as ambition, drive, status, intelligence, emotional stability, and mature age. Women scrutinize these personal qualities carefully because they reveal a man’s potential.
Potential, however, is not enough. Because many men with a high resource potential are themselves discriminating and are at times content with casual sex, women are faced with the problem of commitment. Seeking love and sincerity are two solutions to the commitment problem. Sincerity signals that the man is capable of commitment. Acts of love signal that he has in fact committed to a particular woman.
To have the love and commitment of a man who could be easily defeated by other men in the physical arena, however, would have been a problematic asset for ancestral women. Women mated to small, weak men lacking in physical prowess would have risked damage from other men and loss of the couple’s joint resources. Tall, strong, athletic men with V-shaped torsos offered ancestral women protection. In this way, their resources and commitment could be secured against incursion. Women who selected men in part for their strength and prowess were more likely to be successful at surviving and reproducing.
Resources, commitment, and protection do a woman little good if her husband sickens or dies, or if the couple is so mismatched that they fail to function as an effective team. The premium that women place on a man’s health ensures that husbands will be capable of providing these benefits over the long haul. And the premium that women place on similarity of interests and traits with their mate helps to ensure the convergence of mutually pursued goals. These multiple facets of current women’s mating preferences correspond precisely with the multiple facets of the adaptive problems faced by our women ancestors thousands of years ago.
Women, of course, do not evaluate potential mates one trait at a time. Men come as whole packages of qualities that must be accepted or rejected altogether.80 This inevitably requires trade-offs. A kind man may be willing to devote his entire life to one woman and have great potential as a father but may have fewer resources to provide. A strong, healthy, attractive man may be a sterling provider of resources and good genes but may be more tempted to be unfaithful. Moreover, many circumstances create shifts in women’s mate preferences—her personal resource acquisition ability, whether she is seeking a long-term mate or a casual sex partner, close kin in proximity, the sex ratio in the mating pool, and the presence of other women who are attracted to a particular man. The reason men have been baffled for so long about what women want is that women’s mate preferences are inherently complex, multifaceted, and context-dependent, reflecting the large number of intricate adaptive challenges our ancestral mothers confronted repeatedly over the long course of human evolutionary history.
Ancestral men were confronted with a different set of adaptive problems. So we must now shift perspective to gaze at ancestral women as potential mates through the eyes of our male forebears.