Breaking Up

“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.”

Why do individuals choose to leave long-term committed relationships?

“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. 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.”

In ancestral times, besides disease, homicide was a major cause of death.

“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.”

Beyond mortality and mate-value decline, additional forces favored the dissolution of long-term pair bonds:

“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.”

Thus, in ancestral environments, three primary reasons could lead to the voluntary disruption of a pair 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.”

To elaborate further,

“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 persist within marriage:

“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. A decision to keep or get rid of one’s mate depends on the outcome of these calculations, which may not be made consciously.”

Mate evaluation processes operate without conscious awareness:

“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.”

How are mates effectively rejected?

“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.”

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.”

Infidelity as a tactic for mate dissolution:

“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. 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.”

Infertility

“Infertility is exceeded only by infidelity as the most frequently cited cause of divorce across societies.”

Infertility and infidelity are the leading causes of divorce worldwide:

“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.”

Women have been found to employ the following breakup tactics:

“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.”

This tactic appears to be effective, as illustrated by the following case:

“The success of this tactic is illustrated by one woman’s account in the study on the breakup of mates. 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.”

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. 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.

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.” 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. Worldwide, adulterous wives are beaten, raped, scorned, verbally abused, and injured by enraged husbands. 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. 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. 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.“

Role of unkind behavior in inducing relationship dissolution:

“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.”

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.”

Implications for a Lasting Relationship

“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.”

The next chapter is titled “Changes Over Time.”