The Dangerous Passion

The Dangerous Passion: Why Jealousy Is Necessary in Love and Sex
by David M. Buss, Ph.D.

Why do men and women cheat on each other? How do men really feel when their partners have sex with other men? What worries women more — men who turn to other women for love or men who simply want sexual variety in their lives? Can the jealousy husbands and wives experience over real or imagined infidelities be cured? Should it be? In this surprising and engaging exploration of men's and women's darker passions, David Buss, acclaimed author of The Evolution of Desire, reveals that both men and women are actually designed for jealousy. Drawing on experiments, surveys, and interviews conducted in thirty-seven countries on six continents, as well as insights from recent discoveries in biology, anthropology, and psychology, Buss discovers that the evolutionary origins of our sexual desires still shape our passions today.

According to Buss, more men than women want to have sex with multiple partners. Furthermore, women who cheat on their husbands do so when they are most likely to conceive, but have sex with their spouses when they are least likely to conceive. These findings show that evolutionary tendencies to acquire better genes through different partners still lurk beneath modern sexual behavior. To counteract these desires to stray — and to strengthen the bonds between partners — jealousy evolved as an early detection system of infidelity in the ancient and mysterious ritual of mating.

Buss takes us on a fascinating journey through many cultures, from pre-historic to the present, to show the profound evolutionary effect jealousy has had on all of us. Only with a healthy balance of jealousy and trust can we be certain of a mate's commitment, devotion, and true love.

Chapter 1

Jealousy is not only inbred in human nature, but it is the most basic, all-pervasive emotion which touches man in all aspects of every human relationship.

— Boris Sokoloff, 1947,
Jealousy: A Psychological Study

Every human alive is an evolutionary success story. If any of our ancestors had failed to survive an ice age, a drought, a predator, or a plague, they would not be our ancestors. If any had failed to cooperate with at least some others in the group or dropped below a minimal position in the social hierarchy, they would have met certain death by being cast out from the group. If even one had failed to succeed in choosing, courting, and keeping a mate, the previously inviolate chain of descent would have irreparably broken, and we would not be alive to tell the tale. Each of us owes our existence to thousands of generations of successful ancestors. As their descendants, we have inherited the passions that led to their success — passions that drive us, often blindly, through a lifelong journey in the struggle for survival, the pursuit of position, and the search for relationships.

We usually think of passion as restricted to sex or love, the burning embrace or constant craving. But it has a broader meaning, referring to the drives and emotional fires that propel us in our quests through life. They sometimes glow quietly, but at other times they burst into full flame. They range from tranquil devotion to violent eruption. Their expression yields life's deepest joys, but also the cruelest suffering. And although we commonly think of passion as a force opposed to reason and rationality, something to be tamed or overcome, passions when properly understood have a crystalline logic, precise purpose, and supreme sensibility.

The drives that stir us out of bed at dawn and hurl us headlong into our daily struggles have two sides. On the positive side, passions inspire us to achieve life's goals. They impel us to satisfy our desire for sex, our yearning for prestige, and our quest for love. The dazzling plays of Shakespeare, the mezmerizing art of Georgia O'Keeffe, and the brilliant inventions of Thomas Edison would not exist if passion had not stirred them from repose and impelled creation. Without passion, we would lie listless in bed, for there would be no motivation to do anything at all.

But passions carry a darker, more sinister side. The same passions that inspire us with love can lead to the disastrous choice of a mate, the desperation of unrequited obsession, or the terror of stalking. Jealousy can keep a couple committed or drive a man to savagely beat his wife. An attraction to a neighbor's spouse can generate intoxicating sexual euphoria while destroying two marriages. The yearning for prestige can produce exhilarating peaks of power while evoking the corrosive envy of a rival and a fall from a greater height. The Dangerous Passion explores both the destructive and triumphant sides of human desires.

Together with many colleagues, my research over the past decade has centered on exploring the nature, origins, and consequences of the passions of men and women, with a special focus on jealousy, infidelity, love, sex, and status. Our goal has been to seek a deeper understanding of what makes men and women tick, the desires that drive people to heights of success or depths of despair, and the evolved mechanisms of mind that define who we are. This book illuminates the dark side of sexual treachery, the mysterious puzzle of romantic love, and the central role of jealousy in our intimate relationships.

Some argue that these mysteries should be left alone, pristine and untrammeled, shielded from the harsh glare of scientific scrutiny. But is the woman who has her freedom and sense of safety crushed by a jealous husband better off unequipped with the knowledge of how to prevent her torment? Is the man obsessed by unrequited love better off failing to understand the underlying reasons for his rejection? Ignorance may sometimes be bliss, but it can also cause needless anguish. My hope is that revealing the underlying logic of dangerous passions will be intellectually illuminating, provide one path for understanding the distress we experience at the hands of our lovers and rivals, and just possibly improve in some small measure the tools for coping with the untamed demons in our lives.

At the center of The Dangerous Passion is an exploration of a hazardous region of human sexuality — the desires people experience for those who are not their regular partners and the jealous shield designed to combat its treacherous consequences.

The Green-Eyed Monster

Think of a committed romantic relationship that you have now, or that you had in the past. Now imagine that your romantic partner becomes interested in someone else. What would upset or distress you more: (a) discovering that your partner is forming a deep emotional attachment, confiding and sharing confidences with another? or (b) discovering that your partner is enjoying passionate sex with the other person, trying out different sexual positions you had only dreamed about? Both scenarios are distressing, of course, but which one is more distressing? If you are like the majority of women we surveyed recently in the United States, the Netherlands, Germany, Japan, Korea, and Zimbabwe, you will find the emotional infidelity more upsetting. The answer seems obvious, at least to women. The majority of men, however, find the prospect of a partner's sexual infidelity more agonizing. The gulf between the sexes in emotional reactions to infidelity reveals something profound about human mating strategies.

The explanation for sex differences in jealousy lies deep in the evolutionary past of the human species. Consider first a fundamental sex difference in our reproductive biology: fertilization takes place inside women's bodies, not men's. Now, internal female fertilization is not universal in the biological world. In some species, such as the Mormon crickets, fertilization occurs internally within the male. The female takes her egg and literally implants it within the male, who then incubates it until birth. In other species, fertilization occurs externally to both sexes. The female salmon, for example, drops her collection of eggs after swimming upstream. The male follows and deposits his sperm on top, and then they die, having fulfilled the only mission in life that evolution gave them. But humans are not like salmon. Nor are we like Mormon crickets. In all 4,000 species of mammals, of which we are one, and in all 257 species of primates, of which we are also one, fertilization occurs internally within the female, not the male. This posed a grave problem for ancestral men — the problem of uncertainty in paternity.

From an ancestral man's perspective, the single most damaging form of infidelity his partner could commit, in the currency of reproduction, would have been a sexual infidelity. A woman's sexual infidelity jeopardizes a man's confidence that he is the genetic father of her children. A cuckolded man risks investing years, or even decades, in another man's children. Lost would be all the effort he expended in selecting and attracting his partner. Moreover, he would lose his partner's labors, now channeled to a rival's children rather than his own.

Women, on the other hand, have always been 100 percent sure that they are the mothers of their children (internal fertilization guarantees that their children are genetically their own). No woman ever gave birth and, watching the child emerge from her womb, wondered whether the child was really hers. One African culture captures this sex difference with a phrase more telling than any technical summary: "Mama's baby, papa's maybe." Biology has granted women a confidence in genetic parenthood that no man can share with absolute certainty.

Our ancestral mothers confronted a different problem, the loss of a partner's commitment to a rival woman and her children. Because emotional involvement is the most reliable signal of this disastrous loss, women key in on cues to a partner's feelings for other women. A husband's one-night sexual stand is agonizing, of course, but most women want to know: "Do you love her?" Most women find a singular lapse in fidelity without emotional involvement easier to forgive than the nightmare of another woman capturing her partner's tenderness, time, and affection. We evolved from ancestral mothers whose jealousy erupted at signals of the loss of love, mothers who acted to ensure the man's commitment.

But who cares who fathers a child or where a man's commitments get channeled? Shouldn't we love all children equally? Perhaps in some utopian future, we might, but that is not how the human mind is designed. Husbands in our evolutionary past who failed to care whether a wife succumbed to sex with other men and wives who remained stoic when confronted with their husband's emotional infidelity may be admirable in a certain light. Perhaps these self-possessed men and women were more mature. Some theories, in fact, propose that jealousy is an immature emotion, a sign of insecurity, neurosis, or flawed character. Nonjealous men and women, however, are not our ancestors, having been left in the evolutionary dust by rivals with different passionate sensibilities. We all come from a long lineage of ancestors who possessed the dangerous passion.

Jealousy, according to this theory, is an adaptation. An adaptation, in the parlance of evolutionary psychology, is an evolved solution to a recurrent problem of survival or reproduction. Humans, for example, have evolved food preferences for sugar, fat, and protein that are adaptive solutions to the survival problem of food selection. We have evolved specialized fears of snakes, spiders, and strangers that are adaptive solutions to ancestral problems inflicted by dangerous species, including ourselves. We have evolved specialized preferences for certain qualities in potential mates, which helped to solve the problems posed by reproduction. Adaptations, in short, exist in modern humans today because they helped our ancestors to combat all of the many "hostile forces of nature," enabling them to successfully survive and reproduce. Adaptations are coping devices passed down over millennia because they worked — not perfectly, of course, but they helped ancestral humans to struggle through the evolutionary bottlenecks of survival and reproduction.

Jealousy, according to this perspective, is not a sign of immaturity, but rather a supremely important passion that helped our ancestors, and most likely continues to help us today, to cope with a host of real reproductive threats. Jealousy, for example, motivates us to ward off rivals with verbal threats and cold primate stares. It drives us to keep partners from straying with tactics such as escalating vigilance or showering a partner with affection. And it communicates commitment to a partner who may be wavering, serving an important purpose in the maintenance of love. Sexual jealousy is often a successful, although sometimes explosive, solution to persistent predicaments that each one of our ancestors was forced to confront.

We are typically not conscious of these reproductive quandaries. Nor are we usually aware of the evolutionary logic that led to this dangerous passion. A man does not think, "Oh, if my wife has sex with someone else, then my certainty that I'm the genetic father will be jeopardized, and this will endanger the replication of my genes; I'm really mad." Or if his partner takes birth-control pills, "Well, because Joan is taking the pill, it doesn't really matter whether she has sex with other men; after all, my certainty in paternity is secure." Nor does a woman think, "It's really upsetting that Dennis is in love with that other woman; this jeopardizes my hold on his emotional commitments to me and my children, and hence hurts my reproductive success." Instead, jealousy is a blind passion, just as our hunger for sweets and craving for companionship are blind. Jealousy is emotional wisdom, not consciously articulated, passed down to us over millions of years by our successful forebears. One goal of The Dangerous Passion is to bring to the surface the deep roots of the inherited emotional wisdom we possess.

Copyright © 2000 by David M. Buss

About the Author

David M. Buss, Ph.D., is a professor of psychology at the University of Texas, Austin, and previously taught at Harvard University and the University of Michigan. He is the author of the highly praised The Evolution of Desire and is internationally known for his expertise on sex, emotions, and the strategies of human mating. He lives in Austin, Texas.