Women marry believing that their husbands will change. Men marry believing that their wives will not change. They are both wrong.
—ANONYMOUS
HUMAN MATING IS rarely a once-in-a-lifetime occurrence. Divorce and remarriage are so common in the United States that nearly 50 percent of all children do not live with both of their genetic parents. Stepfamilies are rapidly becoming the norm, not the exception. Contrary to some beliefs, this is not a recent phenomenon, nor does it reflect a dramatic decline in family values. Divorce specifically and the dissolution of long-term mating relationships more generally are universal across cultures. Roughly 85 percent of Americans have experienced at least one breakup of a committed mating relationship.1 Among the !Kung of Botswana, 134 marriages out of 331 recorded ended in divorce—about 40 percent.2 Among the Ache of Paraguay, the average man and woman are married and divorced more than eleven times each by the time they reach the age of forty.3
People end committed relationships for many reasons. A spouse may start imposing new or larger costs, for example, or a better opportunity for a mate may come along. Staying in a bad relationship can be costly—lost resources, missed mating opportunities, physical abuse, inadequate care for children, and emotional abuse. These costs all interfere with successful solutions to the critical adaptive problems of survival and reproduction. New mating opportunities, superior resources, better child care, and better allies are some of the benefits that may flow to people who leave bad relationships.
Adaptive Problems Leading to Breakups
Many mates in ancestral times became injured and died before old age. Men, for example, sustained wounds or were killed in combat between warring tribes. The paleontological record reveals fascinating evidence of aggression between men. Pieces of spears and knives have been found lodged in the remains of human rib cages. Injuries to skulls and ribs are found more frequently on male than on female skeletons, revealing that physical combat was primarily a male activity. Intriguingly, more injuries are located on the left sides of skulls and rib cages, suggesting a greater prevalence of right-handed attackers. The earliest known homicide victim in the paleontological record is a Neanderthal man who was stabbed in the chest by a right-hander roughly 50,000 years ago.4 These highly patterned injuries cannot be explained as accidents. They demonstrate that injury and death at the hands of other people have been recurrent hazards in human evolutionary history.
Traditional tribes today do not escape the damage done by male aggression. Among the Ache, for example, ritual club fights occur only among men, and they often result in permanent disabilities and death.5 A woman whose husband goes off to a club fight can never be sure that he will return unharmed. Among the Yanomamö, a boy does not achieve full status as a man until he has killed another man. Yanomamö men display their scars proudly, often painting them bright colors to draw attention to them.6 Men have fought in wars throughout human history, exposing themselves to grave risks.
Violence at the hands of other men was not the only way an ancestral man could die. Hunting has always been a male-dominated human enterprise, and ancestral men risked injury, particularly when hunting large game, such as wild boar, bison, or buffalo. Lions, panthers, and tigers roamed the African savanna, inflicting injury or death on the unwary, the unskilled, the imprudent, or the unlucky. Some men accidentally plunged off cliffs or fell from trees. In human ancestral environments, since a woman’s husband had a chance of dying first or becoming so seriously injured as to cripple his ability to hunt or to protect her, it would have been highly adaptive for her to assess and encourage alternative mates.
Ancestral women never warred and rarely hunted. Women’s gathering activities, which yielded 60 to 80 percent of the family’s food resources, were far less dangerous.7 Childbirth, however, took its toll. Without modern medical technology, many women failed to survive the dangerous journey of pregnancy and childbirth. A man left mateless by his wife’s death would have had to start the search and courting process from scratch, unless he had psychological adaptations that anticipated this possibility and caused him to lay the groundwork for securing a replacement. It would have paid for both men and women not to wait until their mate’s death to start evaluating potential alternatives.
Injury, disease, or the death of a mate were not the only hazards to force ancestral mates to look elsewhere. A woman’s husband could lose status within the group, be ostracized, become dominated by a rival male, prove to be a bad father, prove to be infertile, fail as a hunter, start abusing her, initiate affairs, direct resources to other women, or turn out to be sexually impotent. A man’s wife could fail at gathering food, mishandle family resources, prove to be a bad mother, prove to be infertile, decline his sexual advances, cheat on him, or get pregnant by another man. Either sex could contract debilitating diseases or become riddled with parasites. Life events sometimes take a terrible toll on a mate full of vitality when initially chosen. Once a selected spouse decreases in value, alternatives become attractive.
A mate’s decline in value and potential death represented only two of the conditions that might have diverted a person’s attention to alternatives. Another critical condition is an increase in one’s own desirability, which opens up an array of alternatives that were previously unobtainable. A man, for example, could sometimes dramatically elevate his status by performing an unusually brave deed, such as killing a large animal, defeating another man in combat, or saving someone’s child from harm. Sudden increases in a man’s status opened up new mating possibilities with younger, more attractive mates or multiple mates, who could make a current mate pale by comparison. Mating options mushroomed for men who managed to boost their status. Because a woman’s value as a mate was closely tied with her reproductive value, she usually could not elevate her desirability to the same extent that men could. Nevertheless, women could improve their mate value by acquiring status or power, showing unusual adeptness at dealing with crises, displaying exceptional wisdom, or having sons, daughters, or other kin who achieved elevated positions within the group. These possibilities for changes in mating value are still with us today.
Another important impetus to break up a mateship was the presence of more desirable alternatives. A desirable mate who had previously been taken could suddenly become available. A previously uninterested person could develop a strong attraction. A member of a neighboring tribe could appear on the scene. And any of these people could be sufficiently desirable to warrant breaking an existing marital bond.
In sum, three major general circumstances could have led an ancestral person to leave a long-term mate: when a current mate became less desirable because of a decrease in abilities or resources or a failure to provide the reproductively relevant resources expected in the initial selection; when the person experienced an increase in his or her own resources or reputation that opened up previously unobtainable mating possibilities; and when compelling alternatives became available. Because these three conditions are likely to have regularly recurred among our ancestors, it is reasonable to expect that humans evolved psychological mechanisms to evaluate the costs and benefits of existing relationships in comparison with the perceived alternatives. These adaptations would have been attuned to changes in the value of a mate, continued to identify and gauge mating alternatives, and led to the pursuit of backup mates or potential replacement mates.
Adaptations for Breaking Up
Ancestral conditions that favored breakups posed recurrent adaptive challenges over human evolutionary history. People who were oblivious to a decrease in their mate’s value, who were totally unprepared to find a new mate in the event of their mate’s death, or who failed to trade up to a higher-quality mate when offered the opportunity would have been at a tremendous reproductive disadvantage compared with those who perceived and acted on these conditions.
It may be disconcerting to acknowledge it, but most people continue to assess outside options while in a committed relationship. Men’s banter, when it does not center on sports or work, often revolves around the appearance and sexual availability of women in their social circles. Married women talk as well about which men are attractive, available, and high in status. These discussions accomplish the critical goals of exchanging information and assessing the mating terrain. It pays to monitor alternatives with an eye toward mating opportunities. Those who stick it out with an undesirable mate through thick and thin may receive our admiration, but their kind would not have reproduced as successfully in ancestral times and are not well represented among us today. Men and women evaluate alternative mating possibilities even if they have no immediate intention to act on them. It pays to plan ahead.
Mate preferences continue to operate during marriage, being directed not just at comparing the array of potential mates but at comparing those alternatives with the current mate. Men’s preference for young, attractive women does not disappear once they make a long-term commitment to a mate; nor does women’s attention to the status and prestige of other men. Indeed, one’s mate provides a handy standard for repeated comparisons. Research from my lab, spearheaded by Dan Conroy-Beam, discovered that happiness in a mateship is partly determined by the discrepancies between one’s partner’s mate value and the value of alternative mates in the local environment. People assess how well their mates stack up to the competition and become unhappy if their mates suffer by these comparisons.8 A decision to keep or get rid of one’s mate depends on the outcome of these calculations, which may not be made consciously.
A man whose increased status opens up better mating alternatives does not think to himself, Well, if I leave my current wife, I can increase my reproductive success by mating with younger, more reproductively valuable women. He simply finds other women increasingly attractive and his current relationship less satisfactory. A woman whose mate abuses her does not think to herself, My reproductive success and that of my children will increase if I leave this cost-inflicting mate. She thinks instead that she had better get herself and her children to safety. Our mateship dissolution adaptations operate without our awareness of the adaptive problems they solve.
People typically need a clear, socially acceptable justification for leaving a long-term mate, one that explains the breakup to friends, to family, and even to themselves. They need a public rationale that preserves, or minimizes the damage to, their social reputation. Although some simply walk away from a relationship, people rarely use this straightforward solution. One effective tactic for expelling a mate, in evolutionary psychological terms, would be to violate the mate’s expectations, so that the mate no longer desired to maintain the relationship. That is, rather than leaving themselves, some people try to drive their partner to take that step. Ancestral men could withhold resources or give signals that investments were being channeled to other women. Women could decrease a man’s certainty of paternity by engaging in infidelities or simply withholding sex from him. Cruel, unkind, inconsiderate, malevolent, harmful, or caustic acts would be effective tactics for expelling a mate for both women and men because such acts violate the universal preferences held by both of them for mates who are kind and empathic. These tactics have in common the exploitation of existing psychological mechanisms in the other sex—adaptations that alert people to the possibility that they have chosen a mate unwisely, or that their mate has changed in unwanted ways, and that perhaps they should cut their losses.
The sex differences in benefits from long-term matings in ancestral times, whereby men’s benefits came from monopolizing a woman’s reproductive capacity and women’s from monopolizing a man’s investments, have profound implications for the causes of separation and divorce. They imply that men and women evaluate changes in their mates over time by very different standards. As a woman ages from twenty-five to forty, for example, she experiences a rapid decline in her reproductive value, although other components of her mate value may increase and compensate for the loss. During a comparable period a man may elevate himself in status and so enjoy an unanticipated avalanche of mating opportunities. Or he may suffer losses and become desperate to keep his current mate. Ancestral men and women broke up, however, for somewhat different reasons that go to the core of the adaptive problems that each gender must solve to mate successfully.
A major source of evidence on breaking up comes from the most extensive cross-cultural study ever undertaken on the causes of divorce. The evolutionary anthropologist Laura Betzig analyzed information from 160 societies and identified forty-three causes of conjugal dissolution recorded by ethnographers who had lived in the society or by native informants who resided in each culture.9 Various constraints, such as the lack of a standard method of gathering data and incomplete data, preclude calculation of the absolute frequencies of the causes of divorce. Nonetheless, the relative frequencies are readily available, and as the number of societies revealing a particular cause of divorce increases, the more likely it is that this cause is a universal cause of divorce. Topping the list of causes of divorce are two key events with direct relevance to reproduction—infidelity and infertility.
Infidelity
The most powerful indicator of a man’s failure to retain access to a woman’s reproductive capacity is her infidelity. The most powerful cue to a woman’s failure to retain access to a man’s resources is his infidelity. Among the forty-three causes of conjugal dissolution, ranging from the absence of male children to sexual neglect, adultery is the single most pervasive cause, being cited in eighty-eight societies. Among those that highlight adultery, there are strong gender differences in prevalence. Although in twenty-five societies divorce follows from adultery by either partner, fifty-four societies sanction divorce only if the wife is adulterous; in only two societies does divorce occur only following the husband’s adultery. Even these two societies can hardly be considered exceptions to the sexual double standard, because an unfaithful wife rarely goes without punishment. In both of these cultures, men are known to thrash their wife upon discovery of her infidelity and occasionally a woman is beaten to death by her husband. Unfaithful wives in these two cultures may not be divorced, but neither do they get off lightly.
The finding that a woman’s infidelity is a more prevalent cause of divorce is especially striking because men are more likely to be unfaithful.10 Alfred Kinsey, for example, found that 50 percent of the husbands but only 26 percent of the wives surveyed had been unfaithful.11 More recent studies find similar gender differences in infidelity rates.12 The sexual double standard in reactions to infidelity is not confined to American culture or to Western societies but is observed across the globe. Its pervasiveness stems from three possible sources. First, men have greater power to impose their will, so that women may be forced to tolerate infidelity in their husbands more often than men are forced to tolerate infidelity in their wives. Second, women worldwide may be more forgiving of their husband’s sexual indiscretions because sexual infidelity per se has been less costly for women than for men over human evolutionary history, unless also accompanied by the diversion of his resources and commitments. Third, women worldwide may more often be forced to tolerate a husband’s infidelity because of the prohibitively high costs of divorce, especially if they have children, who curtail women’s value on the mating market. For all these reasons, a wife’s unfaithfulness more often causes an irrevocable rift that ends in divorce.
Knowing that infidelity causes conjugal dissolution, some people may use it intentionally to get out of a bad marriage. In a study of the breakup of mates, we asked one hundred men and women which tactics they would use to get out of a bad relationship. Subsequently, a different group of fifty-four individuals evaluated each tactic for its effectiveness in accomplishing the goal.13 One common method for getting rid of an unwanted mate was to start an affair, perhaps by sleeping around in an obvious manner or arranging to be seen with a member of the other gender in some other questionable situation.
Sometimes an actual affair is not carried out but is merely alluded to or implied. People use the tactics of flirting with others or telling a partner that they are in love with someone else so that the mate will end the relationship. A related tactic is to express a wish to date other people in order to be sure that the two of them are truly right for each other, a means of gracefully exiting from the relationship through a gradual transition out of commitment.
So widely accepted is infidelity as a reason to get rid of a mate that people sometimes exploit it, even if no actual infidelity has occurred. In Truk, for example, if a husband wants to terminate a marriage, he has merely to spread a rumor about his wife’s adultery, pretend to believe it, and leave her in indignation.14 Apparently, people care about justifying a marital dissolution to their social circles. Pretending that an affair has occurred provides this justification because infidelity is so widely regarded as a compelling reason for breaking up.
Infertility
Although ring doves tend to be monogamous—more so than many bird species—they experience a divorce rate of about 25 percent a season. The major cause of breaking a bond is infertility—the failure of the pair to reproduce.15 Pairs of ring doves that produce chicks in one breeding season are highly likely to mate again the next season; those that fail to reproduce in one season seek out alternative mates the next season.
Failure to produce children is also a leading cause of divorce for humans. Couples with no children divorce far more often than couples with two or more children. According to a United Nations study of millions of people in forty-five societies, 39 percent of divorces occur when there are no children, 26 percent when there is only a single child, 19 percent when there are two, and fewer than 3 percent when there are four or more. The toll on marriage caused by childlessness occurs regardless of the duration of the marriage.16 Children strengthen marital bonds, reducing the probability of divorce, by creating a powerful commonality of genetic interest between a man and a woman. Failure to produce offspring that transport the genes of both parents into the future deprives a couple of this powerful common bond.
Infertility is exceeded only by infidelity as the most frequently cited cause of divorce across societies. In the cross-cultural study of conjugal dissolution, seventy-five societies reported infertility or sterility as a cause of divorce. Of these, twelve specified the sterility of either the husband or the wife. But sterility, like adultery, appears to be strongly gender-linked. Whereas sterility ascribed exclusively to the man was cited as a cause of divorce in twelve societies, sterility ascribed exclusively to the woman was cited in thirty societies—perhaps reflecting another type of double standard by which women are blamed more than men. In the remaining twenty-one societies, it is impossible to discern whether or not sterility on the part of the man, the woman, or both was a cause.
Not all societies sanction divorce. Where divorce is not authorized, however, provisions are often made for separating a man and woman who do not produce children. In the Andaman Islands off the southern coast of Asia, for example, a marriage is not regarded as consummated unless a child is born.17 Many villages in Japan hold off recording a marriage until long after a wedding, and frequently the marriage is not entered into the family register in the village office until the first child is born.18 When marriages are not regarded as legally legitimate until children are born, infertility effectively becomes a cause of marital dissolution.
Old age is linked with lower fertility. This linkage is stronger in women than in men, but even though sperm quality and concentration per ejaculate declines somewhat with age, men in their sixties, seventies, and eighties can still sire children, and they do. Among the Yanomamö, one particularly productive man had children whose ages spanned fifty years. Among the Tiwi of northern Australia, older men frequently monopolize women thirty or more years younger and sire children with them. Although couples in Western culture tend to be more similar in age than those among the Tiwi and Yanomamö, it is not uncommon for a man to divorce a postmenopausal wife and start a new family with a younger woman.19
The difference in the reproductive biology of men and women leads to the expectation that older age in a wife will lead to divorce more often than older age in a husband. Although the cross-cultural study on conjugal dissolution did not find old age to be a frequently cited cause of divorce, it was cited in eight societies studied, and in all eight it was the old age of the woman, never the man, that caused divorce.20 When men divorce, they almost invariably marry younger women.
In evolutionary terms, it makes perfect sense that infertility and infidelity are the most prevalent causes of divorce worldwide. Both represent the strongest and most direct failures to deliver the reproductive resources that provide the evolutionary raison d’être for long-term mating. People do not consciously calculate that their fitness suffers from these events. Rather, infidelity and infertility are adaptive problems that exerted selection pressure on human ancestors for a psychology attuned to reproductive failures. Just as having sex tends to lead to the production of babies even though the people involved may have no awareness of the reproductive logic involved, so anger leads a person to leave an unfaithful or infertile mate, with no conscious articulation of the underlying adaptive logic being required. The fact that couples who are childless by choice are nonetheless devastated by infidelity shows that our psychological mechanisms continue to operate in modern contexts, even those far removed from the selection pressures that gave rise to them.
Sexual Withdrawal
A wife who refuses to have sex with her husband is effectively depriving him of access to her reproductive value, although neither mate necessarily thinks about it in these terms. Since sex throughout human evolutionary history has been necessary for reproduction, depriving a man of sex may eliminate the reproductive dividends on the investment that he has expended in obtaining his wife. It may also signal that she is allocating her sexuality to another man. Men have evolved psychological adaptations that alert them to this form of interference with their sexual strategies.
In the cross-cultural study on conjugal dissolution, twelve societies identified the refusal to have sex as a cause of conjugal dissolution. In all these societies the cause was attributed exclusively to the wives’ refusal, not the husbands’.21 My lab’s study of the breakup of mates also found sexual refusal to be a major tactic for getting rid of unwanted mates. Women described their tactics for breaking up variously as refusing to have physical contact with their mate, becoming cold and distant sexually, refusing to let her mate touch her body, and declining sexual requests. These tactics were employed almost exclusively by women.22
The success of this tactic is illustrated by one woman’s account in the study on the breakup of mates.23 She complained to a friend that her repeated attempts to break off with her husband had failed. She wanted advice. Further discussion revealed that, although she seriously wanted to get rid of her husband, she never had refused his sexual advances. Her friend suggested that she try it. A week later she reported that her husband had become enraged at her sexual refusal and, after two days, had packed his bags and left. They were divorced shortly thereafter. If women give sex to get love and men give love to get sex, then depriving a man of sex may be a reliable way to stop his love and hasten his departure.
Lack of Economic Support
A man’s ability and willingness to provide a woman with resources are central to his mate value, central to her selection of him as a partner, central to the tactics that men use to attract mates, and central to the tactics that men use to retain mates. In evolutionary terms, a man’s failure to provide resources to his wife and her children should therefore have been a major gender-linked cause of breakups. Men who are unable or unwilling to supply these resources fail to fulfill a key criterion on which women initially select them.
Provisioning failure by men is a cause of divorce worldwide. In the cross-cultural study on conjugal dissolution, twenty societies cited inadequate economic support as a cause of divorce, four cited inadequate housing, three cited inadequate food, and four cited inadequate clothing. All these causes were ascribed solely and exclusively to men. In no society did a woman’s failure to provide resources constitute grounds for divorce.24
The seriousness of a man’s lack of economic provision is illustrated by the report of a woman in her late twenties who participated in a study of marital separation:
My husband lost a series of jobs and was very depressed. He just couldn’t keep a job. He had a job for a couple of years, and that ended, and then he had another for a year, and that ended, and then he had another. And then he was really depressed, and he saw a social worker, but it didn’t seem to be helping. And he was sleeping a lot. And I think one day I just came to the end of the line with his sleeping. I think I went out one night and came back and he hadn’t even been able to get out of bed to put the children to bed. I left them watching television and there they were when I came back. The next day I asked him to leave. Very forcefully.25
In contemporary America, women who make more money than their husbands tend to leave them. One study found that the divorce rate among American couples in which the woman earns more than her husband is 50 percent higher than among couples in which the husband earns more than his wife.26 Men whose wives’ careers blossom sometimes express resentment. In a study on the causes of divorce among women, one woman noted that her husband “hated that I earned more than he did; it made him feel less than a man.” Women also resent husbands who lack ambition. Another woman noted: “I worked full-time, while he worked part-time and drank full-time; eventually, I realized I wanted more help getting where I’m going.”27 Women eject men who do not fulfill their preference for a mate who provides resources, especially when they can earn more.
Conflict Among Multiple Wives
Polygyny is a widespread practice across cultures. An analysis of 853 cultures revealed that 83 percent of them permitted polygyny. In some West African societies, 25 percent of all older men have two or more wives simultaneously.28 Even in cultures in which polygyny is not allowed legally, it sometimes occurs. One study estimated that there are 25,000 to 35,000 polygynous marriages in the United States, mostly in western states.29 Another study of 437 financially successful American men found that some maintained two separate families, each unknown to the other.30
From a woman’s perspective, a major drawback of her husband taking additional wives is that resources channeled to another wife and her children are denied to her and her children. Although co-wives may derive significant benefits from one another’s presence, such as help with raising children, often one wife’s gain is another wife’s loss. The cross-cultural study on conjugal dissolution found polygyny to be a cause for divorce in twenty-five societies, largely because of conflict among the man’s co-wives.
Conflict among co-wives may have been an adaptive problem that polygynous men in ancestral times had to solve to maintain control over their wives. The problem was how to keep all wives happy so that none left; defection would deprive the man of significant reproductive resources. Some polygynous men adopted strict rules about resource distribution, offering each wife equal attention and equal sex. Among the Kipsigis in Kenya, wives of polygynous husbands have their own plots of land, which are divided equally among them by the husband.31 Kipsigis men maintain a separate residence apart from their wives, and they alternate the days spent with each wife, carefully allocating time equally. One writer on ancient Islamic cultures in the Middle East concluded: “You should have four wives if your fortune warrants it, and if you can give each one of the four the same attention, like sum for her necessaries, and a separate household.”32 All these tactics tend to minimize conflict among co-wives. Sororal polygyny, in which co-wives are sisters, also tends to minimize conflict, suggesting that genetic relatedness creates a convergence in the interests of women.33
Despite men’s efforts to keep peace among co-wives, women in societies such as Gambia often leave their husbands when they indicate that they plan to acquire a second wife, even though polygyny is legal.34 Wives find it difficult to share their husband’s time and resources with other women.
Cruelty and Unkindness
Worldwide, one of the most highly valued characteristics in a committed mate is kindness. It signals a willingness to engage in a cooperative alliance, an essential ingredient for success in long-term mating. Disagreeable people make poor mates. Mates who are irritable, violent, abusive, derogatory, beat children, destroy possessions, neglect chores, and alienate friends impose severe costs psychologically, socially, and physically.
Given these costs, cruelty, maltreatment, and ruthlessness rank among the most frequent causes of marital breakup in the cross-cultural study on conjugal dissolution, cited in fifty-four societies. In all cultures these traits are exceeded only by adultery and infertility as causes for splitting up.35 According to one study of marital dissolution, 63 percent of divorced women reported that their husbands abused them emotionally, and 29 percent reported that their husbands abused them physically.36
Unkindness and psychological cruelty may in some cases be related to events that occur during the course of a marriage, particularly adultery and infertility. Infertility, for example, often sparks harsh words between mates in tribal India. One Indian husband said: “We went to each other for seven years till we were weary, and still there was no child; every time my wife’s period began she abused me saying, ‘Are you a man? Haven’t you any strength?’ And I used to feel miserable and ashamed.”37 Eventually, the couple divorced.
Adultery also provokes cruelty and unkindness. When a Quiche woman commits adultery, her husband is likely to nag, insult, scold, abuse, and even starve her.38 Worldwide, adulterous wives are beaten, raped, scorned, verbally abused, and injured by enraged husbands.39 Thus, some forms of unkindness are evoked by reproductively damaging events that occur within the marriage. Cruelty and unkindness, in other words, may in part be symptoms of other underlying causes of divorce. Psychological adaptations and behavioral strategies become activated to solve these costly problems.
In other cases, unkindness is a personality characteristic of one spouse that is stable over time.40 In my lab’s study of newlywed couples, we examined the links between the personality characteristics of one spouse and the problems they caused their mates. The wives of disagreeable husbands expressed distress because their husbands were condescending, physically abusive, verbally abusive, unfaithful, inconsiderate, moody, insulting, and self-centered.41 The wives of disagreeable men complain that their husbands treat them as inferiors, demand too much time and attention, and ignore their wives’ feelings. They slap their wives, hit them, and call them nasty names. They have sex with other women. They fail to help with the household chores. They abuse alcohol and insult their wives’ appearance. Not surprisingly, spouses of disagreeable people tend to be miserable with the marriage, and by the fourth year of marriage many seek separation and divorce.
Given the premium that people place on kindness in a mate, it is not surprising that one of the most effective tactics for getting rid of a bad mate is to act mean, cruel, caustic, and quarrelsome. Men and women say that effective tactics for getting mates to leave include treating them badly, insulting them to others publicly, intentionally hurting their feelings, creating a fight, yelling without explanation, and escalating a trivial disagreement into a fight.
Cruelty and unkindness are used worldwide as a tactic for expelling a mate. Among the Quiche, when a husband wants to get rid of his wife, often because of her infidelities, he makes her position unbearable through a variety of means: “The undesired wife is nagged, insulted, and starved; her husband scolds and abuses her; he is openly unfaithful. He may marry another woman or even outrage his wife’s dignity by introducing a prostitute into the house.”42 All these cruel acts reflect the opposite of the kindness that is central to men’s and women’s universal preferences in a mate.
Mate Ejection Tactics
Extricating oneself from a committed mateship can be diabolically difficult. The rejected partner might not want to let go. Family and friends sometimes apply pressure to stay together. Shared children complicate the disentangling. And in our modern environment, divorce laws and intertwined finances can extend the process of separation from months to years.
Some evolutionary psychologists argue that we have evolved specialized mate ejection adaptations to facilitate breakups.43 Although the scientific study of mate ejection tactics is in its infancy, it has yielded a few key insights. One tactic is simply to tell the partner straighforwardly that both should start seeing other people. Another is to begin having sex with others and let the partner find out—a tactic judged to be one of the most effective, albeit potentially dangerous. Variants include having sex with a partner’s friend, being seen at social gatherings with other potential mates, or leaving evidence of an affair in plain sight so that a partner will discover it.
A third tactic is withdrawal of various kinds of resources. Some mates simply cease showing affection, stop saying “I love you,” and stop having sex with the partner. Some stop defending the partner when insulted by others or derogated publicly. Withholding benefits inherent in the mateship sometimes causes the partner to leave for greener mating pastures. Predictably, men are more likely than women to stop giving gifts and other economic resources to the partner as a means of mate expulsion. Women are more likely than men to refuse to have sex with their partner and decline their partner’s sexual advances.
The flip side of withholding benefits is inflicting costs. Both men and women become more irritable with their partners and pick fights over small things. When verbal abuse sometimes escalates to physical abuse, such as slapping or hitting, a partner may flee to escape incurring these costs. Because cruelty and unkindness are key causes of dissolution, people sometimes ramp up these unsavory tactics to hasten a breakup.
In the modern environment, a common tactic is “ghosting”—ceasing all communications, such as texting or emailing. Some remove the partner as a “friend” from their Facebook page or change their Facebook status from “in a relationship” to “single.” These behaviors send strong rejection signals to the partner and also have the effect of communicating to the broader social network that the relationship is over.
All mate ejection tactics carry potential costs, which range from reputational damage to an ex seeking revenge. The cliché “hell hath no fury like a woman scorned” turns out to apply at least as much to men. Indeed, men are more likely than women to seek revenge using abhorrent tactics such as stalking or posting nude photos of their ex on revenge websites.44 Consequently, those who initiate breakups often attempt to curtail these costs. Saying, “It’s not you, it’s me,” and “I think we should be ‘friends,’” are classic efforts in this direction and are sometimes successful.
Regardless of whether someone is getting ejected or doing the ejecting, both face new adaptive problems after a breakup—problems that require coping strategies.
Tactics for Coping with Breakups
Breaking up a romantic relationship is among the most traumatic life events people experience. In studies of stressful life events, it always ranks in the top five. Only experiences such as the death of a child or the death of a spouse are seen as more stressful. Friendship networks can become strained, and plunging into the mating market anew can be frightening. Breakups can threaten one’s social status since our mates are often seen by others as key contributors to the esteem in which we are held. Moreover, breakups often end the flow of benefits to which we have become accustomed, be they economic, sexual, or social.
The scientific study of coping tactics has just broken ground.45 Women and men alike often try to remain friends with their exes so that the benefits of the relationship do not cease entirely or to minimize the chances of the former partner seeking revenge. Some do the opposite, however, and avoid the ex entirely. Women more than men tap their friendships to discuss the former relationship, hash out its details, mull over what went wrong, and ruminate over future prospects. Both genders sometimes seek sex with others. As one woman we interviewed put it, “The best way to get over a man is to get under another one.”46
Women are more likely than men to go shopping as a coping tactic.47 Shopping for new clothes or makeup can enhance a woman’s self-esteem and increase her physical attractiveness, paving the way for reentry into the mating market.
Some cope with breakups by seeking solace in alcohol or drugs. Some ruminate endlessly, prolonging their pain by keeping tabs on their former partner’s whereabouts or dating activities and monitoring their online presense. And some start stalking their ex in an attempt to remate with them, to interfere with their ex’s attempts to remate, or simply to seek revenge.48
Eventually, most people move on, reenter the mating market, and begin the process of mate selection, mate attraction, and courtship all over again.
Implications for a Lasting Relationship
The major causes of marital dissolution worldwide are those that historically caused damage to reproductive success by imposing reproductive costs and interfering with preferred mating strategies. The most damaging events and changes are infidelity, which can reduce a husband’s confidence in paternity and deprive a wife of some or all of the husband’s resources; infertility, which renders a couple childless; sexual withdrawal, which deprives a husband of access to a wife’s reproductive value or signals to a wife that he is channeling his resources elsewhere; a man’s failure to provide economic support, which deprives a woman of the reproductively relevant resources inherent in her initial choice of a mate; a man’s acquisition of additional wives, which diverts resources from a particular spouse; and cruelty and meanness, which involve abuse, defection, affairs, and an unwillingness to continue a cooperative alliance.
The implications of these fundamental trends in human mating psychology for a lasting relationship are profound. To maximize the chances of preserving a long-term bond, couples would do well to remain faithful; produce children together; secure ample economic resources; act kind, generous, and understanding; and attend to their mate’s sexual and emotional desires. These actions do not guarantee a successful relationship, but they increase the odds substantially.
Unfortunately, not all damaging events and changes can be prevented. Environments impose hostile forces that no one can control, such as infertility, old age, decreased sexual desire, disease, status loss, social ostracism, and death. These forces can crush a mate’s value irrevocably, despite the best intentions. Alternative potential mates sometimes offer to provide what is lacking, so evolution has shaped psychological mechanisms that dispose people to leave their mates under these circumstances—mate-switching adaptations.49
Adaptations that function to attend to the shifting circumstances of mating cannot be easily turned off. In ancestral times, it frequently paid reproductive dividends in the event of the loss of a mate to be prepared by maintaining alternative prospects and to trade up when possible. Those who were caught unprepared, who failed to play in the field of possibilities, or who were unwilling to leave a reproductively damaging mate were less likely to produce descendants. Because the costs incurred and the benefits bestowed by a current mate must always be evaluated relative to those available from alternative mates, the psychological mechanisms of mate switching inevitably include comparisons. Unfortunately for lifelong happiness, a current mate sometimes falls short and fails to measure up to attractive available alternatives.
Most of these hostile forces are still with us today. A mate’s status can rise or fall, infertility traumatizes otherwise joyful couples, infidelities mount, and the sadness of aging turns the youthful frustration of unrequited love into the despair of unobtainable love. These events activate adaptations that evolved to deal with breakups, causing people to avoid threats to their reproduction. These mechanisms cannot be easily turned off. They cause people to seek new mates and sometimes to break up repeatedly as adaptively significant events emerge over the lifetime.