This chapter explores sex-specific trajectories in mate value and their behavioral consequences.

Changes over Time

An alpha male can lose dominance over time:

“Although there were four adult males in the troop, Yeroen was responsible for nearly 75 percent of all matings when the females came into estrus.

As Yeroen grew older, however, things began to change. A younger male, Luit, experienced a sudden growth spurt and started to challenge Yeroen’s status. Luit gradually stopped displaying the submissive greeting to Yeroen, brazenly showing his fearlessness. Once, Luit approached Yeroen and smacked him hard, and another time Luit used his potentially lethal canines to draw blood. Most of the time, however, the battles were more symbolic, with threats and bluffs in the place of bloodshed. Initially, all the females sided with Yeroen, allowing him to maintain his status. One by one they defected to Luit, however, as the tide turned. After two months, the transition was complete. Yeroen was dethroned and began displaying the submissive greeting to Luit. Mating changes followed. While Luit achieved only 25 percent of the matings during Yeroen’s reign of power, his sexual access doubled to 50 percent when he took over. Yeroen’s sexual access to females dropped to zero.”

As in chimpanzees, human status hierarchies are not static:

“With humans as with chimpanzees, nothing in mating remains static over a lifetime. An individual’s value as a mate changes, depending on gender and circumstances. Because many of the changes individuals experience have occurred repeatedly over human evolutionary history, we have evolved psychological adaptations designed to deal with them. A person who steadily ascends a status hierarchy may suddenly be passed by a more talented newcomer. A hunter’s promise may be cut suddenly short by a debilitating injury. An older woman’s son may become the chief of her tribe. An ignored introvert, long regarded as occupying the bottom rungs of desirability as a mate, may achieve renown through a dazzling invention that is useful to the group. A young married couple bursting with health may tragically discover that one of them is infertile. Ignoring change would have been maladaptive, impeding solutions to critical challenges. We have evolved psychological mechanisms designed to alert us to these changes and motivate us to take problem-solving action.”

Changes in a Woman’s Mate Value

“Because a woman’s desirability as a mate is strongly determined by cues to her reproductivity, that value generally diminishes as she gets older. The woman who attracts a highly desirable husband at age twenty will typically attract a less desirable husband at age forty.”

So a woman’s reproductive value generally diminishes as she ages. Accordingly, perceived female attractiveness declines with age.

“The effect of aging on a woman’s mate value shows up in the changing perceptions of attractiveness through life. In one study in Germany, thirty-two photographs were taken of women ranging in age from eighteen to sixty-four. A group of 252 men and women, from sixteen to sixty years of age, then rated each photograph for its attractiveness on a 9-point scale. The age of the subjects of the photographs strongly determined judgments of female attractiveness, regardless of the age or sex of the rater. Young women drew the highest ratings, old women the lowest. These age effects are even more pronounced when men do the ratings. The change in the perceived attractiveness of women as they move through life is not an arbitrary aspect of a particularly sexist culture. Rather, this change in perceptions reflects the universal psychological adaptations in men that equate cues to a woman’s youth with her value as a mate.”

Some mate preferences depend on individual circumstances:

“Consider the real-life case of a highly successful fifty-year-old business executive who had six children with his wife. She developed a debilitating disease and died young. He subsequently married a woman three years older than himself, and his new wife devoted a major share of her effort to raising his children. To this man, a younger woman who had less experience in child rearing and who wanted children of her own would have been less valuable and might have interfered with his goal of raising his own children. A fifty-three-year-old woman may be especially valuable to a man with children and less valuable to a man with no children who wants to start a family. To the individual selecting a mate, averages are less important than particular circumstances.

The same woman can have a different value to a man when his circumstances change. In the case of the business executive, after his children reached college age, he divorced the woman who had helped raised them, married a twenty-three-year-old Japanese woman, and started a second family. His behavior may have been ruthless and not very admirable, but his circumstances had changed. From his individual perspective, the value of his second wife decreased precipitously when his children were grown, and the attractiveness of the younger woman as his third wife increased to accompany his new circumstances.”

As women age, reproductive success becomes less a matter of producing additional offspring and more a matter of nurturing existing children:

“From the wife’s perspective, as her direct reproductive value declines with age, her reproductive success becomes increasingly linked with nurturing her children, the vehicles that transport her genes into the future. From her husband’s perspective, her parenting skills constitute a valuable and virtually irreplaceable resource. Women often continue to provide economic resources, domestic labor, social status, and other resources, many of which decline less dramatically with age than her reproductive capacity and some of which increase. Among the Tiwi tribe, for example, older women can become powerful political allies of their mates, offering access to an extended network of social alliances and even helping their husbands acquire additional wives. But from the perspective of other men on the mating market, an older woman’s desirability as a prospective mate is generally low, not only because her direct reproductive value has declined but also because her efforts may already be monopolized by the care of her existing children and eventually her grandchildren.”

Changes in Sexual Desire

“One of the most prominent changes within marriage over time occurs in the realm of sex. Among newlywed couples, with each passing year men increasingly complain that their wives withhold sex. Although only 14 percent of men complain that their newlywed brides have refused to have sex during the first year of marriage, 43 percent express this feeling four years later. Women’s complaints that their husbands refuse to have sex with them increase from 4 percent in the first year to 18 percent in the fifth year. Both men and women increasingly charge their partner with refusing sex, although more than twice as many men as women voice this complaint.”

The transition to parenthood alters sexual frequency:

“The arrival of a baby depressed the frequency of sex even more: after the birth, the rate of intercourse averaged about one-third of what it had been during the first month of marriage. Although more extensive studies over longer time periods are needed to confirm this finding, it suggests that the birth of a baby has a long-lasting effect on marital sex, as mating effort shifts to parental effort.”

Changes in Commitment

Marital commitment is often experienced as declining over time, as reflected in reduced affection and attentiveness.:

“Women and men become increasingly distressed by their partner’s failure to show affection and attention, which suggests a lowered commitment to the relationship. Women are more distressed than men by declining affection. Whereas only 8 percent of newlywed women complain about their partner’s failure to express love, 18 percent of women voice this complaint by the time they are four years into the marriage.¹³ In comparison, only 4 percent of newlywed men are upset about their wives’ failure to express love, which doubles to 8 percent by the fourth year of marriage. Whereas 64 percent of newlywed women complain that their husbands sometimes fail to pay attention when they speak, 80 percent of women are disturbed by this behavior by the fourth and fifth years of marriage. Fewer husbands overall show distress about their partners’ inattentiveness, but the increase in this complaint over time parallels that of their wives, rising from 18 percent to 34 percent during the first four years of marriage.”

In addition, increasing inattention to a partner’s feelings is observed over time:

“Another indication of the withdrawal of commitment over time is one spouse ignoring the other’s feelings. Among newlywed women, 35 percent express distress about having their feelings ignored, whereas four years later this figure has jumped to 57 percent. The comparable figures for complaints by men are 12 percent in the first year and 32 percent in the fourth. These changes signify a gradual diminution of commitment to a spouse over time, which occurs for both sexes but is more upsetting to women than to men.”

Another source of tension over time is the increase in perceived demands for attention and commitment:

“While women are more disturbed about men’s increasing failure to show commitment through affection and attention, men are more distressed by their wives’ growing demands for commitment. Whereas 22 percent of newlywed men complain that their wives demand too much of their time, 36 percent of husbands express upset about this demand by the fourth year of marriage. The comparable figures for women are only 2 percent and 7 percent. Similarly, 16 percent of newlywed men express distress over their wives’ demands for attention, whereas 29 percent voice this complaint in the fourth marital year. The comparable figures for women are only 3 percent and 8 percent. Thus, although both genders show increasing distress about their partners’ demands for commitment, more men than women are troubled by these changes.”

In the context of jealousy, men intensify mate-guarding toward younger wives, whereas women’s mate-guarding is largely unrelated to their partner’s age:

“Husbands of younger women were more likely to glare at other men who paid attention to their wives and sometimes threatened them with bodily harm. In contrast, wives’ efforts to keep older husbands were just as frequent as their efforts devoted to keeping younger husbands. Regardless of the husband’s age, there was no difference in women’s vigilance, monopolization of time, and appearance enhancement tactics. The intensity of women’s efforts to guard their mates is unrelated to the age of the man, showing a marked contrast to men’s reliance on a woman’s age to calibrate the intensity of their guarding.”

Changes in Men’s Mate Value

“While women’s desirability as mates declines predictably with age, the same does not apply to men’s. The reason is that many of the key qualities that contribute to a man’s value are not as closely or as predictably linked with age. These components include a man’s intelligence, cooperativeness, parenting proclivities, political alliances, kin networks, coalitions, and, importantly, ability and willingness to provide resources to a woman and her children.”

Male and female mate value follow markedly different age-related trajectories:

“Men’s value in supplying resources, indicated by cues such as income and social status, shows markedly different changes with age than women’s reproductive value. There are two important differences: men’s resources and social status typically peak much later in life than women’s reproductive value, and men differ more markedly from one another in the resources and social status they accrue. Men’s resources and status sometimes plummet, sometimes remain constant, and sometimes skyrocket with increasing age, whereas women’s reproductive value declines steadily and inexorably with age.”

Male social status is typically acquired later in life rather than in youth:

“In no known culture do teenage boys enjoy the highest status. Among the Tiwi tribe, men are typically at least thirty years old—and often middle-aged—before they are in a position of sufficient status to acquire a wife or two. Young Tiwi men lack the political alliances to garner much status.”

This pattern is also evident in Western societies:

“In the decade between the ages of twenty-five and thirty-four, men’s income attains only two-thirds of its eventual peak. Not until the decades from ages thirty-five to fifty-four does men’s income in the United States achieve its peak. From age fifty-five on, men’s income declines, undoubtedly because some men retire, become incapacitated, or lose the ability to command their previous salaries. These income averages conceal great variability, because some men’s resources continue to increase throughout their old age, whereas other men remain poor throughout their lives.”

Men and women of similar age tend to differ in mate desirability:

“Because older men tend to have more status and resources than younger men, men and women of the same age differ on average in their value as mates. In the same decade between the ages of sixteen and twenty-five when women peak in fertility and reproductive value, men’s income and status are typically the lowest that they will be in their adult lives. When most women between the ages of thirty-five and forty-four are rapidly approaching the end of their reproductive years, most men in the same decade are just approaching the peak of their earning capacity. To the extent that the central ingredients of desirability are a woman’s reproductive value and a man’s resource capacity, men and women of comparable age are not typically comparable in desirability.”

Earlier Death of Men

Low mate desirability in men is associated with increased risk-taking behavior:

“In short, men low in desirability, as indicated by being unemployed, unmarried, and young, seem especially prone to risk taking, which sometimes becomes lethal. The point is not that killing per se is necessarily an adaptation but rather that men’s evolved sexual psychologies are designed to respond to dire mating conditions by increasing the amount of risk they are willing to take.”

A Mating Crisis—Especially for Educated Women

Skewed sex ratios have consequences that extend beyond mate choice. Changes in the balance between men and women across the lifespan alter mating strategies, intensify competition, and can increase the risk of coercive behavior among men with low mate value:

“The existence of large numbers of men who are unable to attract a mate may also increase sexual aggression and rape. Violence often becomes the strategy of people who lack resources that would otherwise elicit voluntary compliance with their wishes. Rape is sometimes perpetrated by marginal men who lack the status and resources that women seek in long-term mates. Furthermore, the likelihood of war is apparently higher in societies with a high ratio of males than in societies with a low ratio of males, supporting the theory that competition among males intensifies at times of a surplus of males.

Changes in the ratio of men to women throughout life cause corresponding shifts in mating strategies. Adolescent men often live in a world where available women are in scarce supply, because women prefer mature men with position and affluence. Young men’s strategies reflect these local conditions of female scarcity, because they engage in highly risky competition strategies, committing the vast majority of violent crimes of sexual coercion, robbery, battery, and murder. In one study, for example, 71 percent of the men arrested for rape were between the ages of fifteen and twenty-nine. These are crimes of coercion against women whom men cannot attract or control through positive incentives.

As meAs women get older, men loosen the grip of guarding, and a higher and higher proportion of women pursue extramarital affairs, reaching a maximum as women approach the end of their reproductive years. Whereas for men affairs are often motivated by the desire for sexual variety, for women affairs are motivated more by emotional goals and may represent an effort to switch mates while they are still reproductively vibrant. Women seem to know that their desirability on the mating market will be higher if they leave their husbands sooner rather than later. After menopause, women shift their effort toward parenting and grandparenting, aiding the survival and reproduction of their descendants rather than continuing to reproduce directly. Women pay for their reproductive strategy of early and rapid reproduction in the currency of a shorter period of fertility.”

Late reproductive years are associated with an increased likelihood of mate switching among women.

“Given all the changes that befall men and women over their lifetimes, it is remarkable that in fact 50 percent of them manage to remain together through thick and thin. The lifelong convergence of interests between two genetically unrelated individuals may be the most extraordinary feat in the evolutionary story of human mating. Just as we have evolved mechanisms that draw us into conflict, we have adaptations that enable us to live harmoniously with the other sex. My lab’s massive cross-cultural study, for example, found that as men and women age they place less value on physical appearance in a mate and more value on enduring qualities such as dependability and having a pleasing disposition—qualities important for long-term mating success. The adaptations that promote this strategic harmony between the sexes, just as much as the mechanisms that produce strife, stem from the adaptive logic of human mating.”

That in some cases relative harmony between the sexes is achieved and long-term cooperation is sustained is a remarkable achievement.

This leads directly to the next and final chapter of The Evolution of Human Desire, “Harmony Between the Sexes.”

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Short Summary:

Human mating dynamics are fundamentally dynamic across the lifespan, shaped by changing status, reproductive capacity, resources, and individual circumstances. Neither dominance nor desirability is fixed: as illustrated in chimpanzees and humans alike, shifts in age, health, status, and opportunity can rapidly alter mating success. Evolution has therefore favored psychological mechanisms that monitor such changes and motivate adaptive responses.

For women, mate value is closely tied to reproductive capacity, which declines predictably with age. This decline is reflected in consistent cross-cultural patterns of perceived attractiveness, largely driven by evolved male preferences for cues to fertility and youth. As direct reproduction becomes less viable, women’s reproductive success increasingly depends on parental and grandparental investment, as well as social, economic, and political contributions—resources that may retain or even increase their value within an established family but reduce desirability on the broader mating market.

Male mate value follows a very different trajectory. Because it is linked more strongly to status, resources, alliances, and competence—qualities that often peak later in life—men’s desirability varies widely and less predictably with age. Social status is rarely attained in youth and typically accumulates through adulthood, a pattern observed in both small-scale societies and modern Western economies. As a result, men and women of the same age are often not comparable in mate desirability, with women peaking earlier in reproductive value and men later in resource capacity.

These shifting asymmetries influence sexual behavior, commitment, jealousy, and conflict within long-term relationships. Over time, sexual frequency tends to decline, particularly after the transition to parenthood, as mating effort gives way to parental effort. Partners increasingly report reduced affection, attentiveness, and emotional responsiveness, alongside growing tension over perceived demands for commitment. Men tend to be more distressed by increasing demands, whereas women are more distressed by declining affection.

Sex differences also emerge in jealousy and mate guarding. Men calibrate guarding intensity strongly to a woman’s age, intensifying efforts toward younger wives, whereas women’s mate-guarding behavior is largely independent of a man’s age. In contexts of low mate value—especially among young, unemployed, unmarried men—risk-taking increases, sometimes lethally, reflecting evolved responses to poor mating prospects rather than violence as an adaptation per se.

At the population level, skewed sex ratios and mating inequalities can intensify competition, coercion, and social instability. At the individual level, changing circumstances can radically alter mate preferences, leading to mate switching, particularly among women approaching the end of their reproductive years. After menopause, women typically redirect effort toward kin investment rather than further reproduction.

Despite these pervasive sources of conflict, divergence, and instability, a striking fact remains: a substantial proportion of men and women sustain long-term pair bonds. With age, both sexes increasingly prioritize traits such as dependability, emotional stability, and cooperativeness—qualities that support enduring partnerships. The ability of two genetically unrelated individuals to achieve relative harmony and long-term cooperation stands as one of the most remarkable outcomes of human mating psychology.

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After reviewing the final chapter, I will turn to an overall review of the book, highlighting what caught my attention most.