The Folly of Fools: The Logic of Deceit and Self-Deception in Human Life - Robert Trivers (2011)

Chapter 5. Deceit, Self-Deception, and Sex


Few relationships have more potential for deceit and self-deception than those between the sexes. Two genetically unrelated individuals get together to engage in the only act that will generate a new human being—sex, an intense experience that is at best ecstatic and at worst deeply disappointing, or when forced, extremely painful and damaging. The act is often embedded in a larger relationship that will permit the two to stay together for years or even life—long enough to raise children. Opportunities for misrepresentation and outright deception are everywhere, and selection pressures are often strong. Likewise, each partner’s knowledge of the other is usually detailed and intense and (absent denial) grows with time.

Sex itself is fraught with psychological and biological meaning at every depth. Are we misrepresenting our level of interest, sexual or romantic, our deeper orientation toward the other, positive or negative, or our very sexual orientation? To analyze deceit and self-deception between the sexes, we must first describe the underlying logic for the evolution of the sexes and relations between them, including sex. Then we can link this to sex differences in deceit and self-deception regarding extra-pair sex, uncertain paternity, the female monthly cycle, female sexual interest, fantasy, betrayal, and murder.

The key to the two sexes, as it is to sex, is the offspring they may produce—the very function of life. In the evolutionary context, there are only two variables we need to pay attention to—genes and parental investment. The offspring is only made up of the two. It receives its genes from both parents (roughly equally) and the investment (that is, labor and resources to build it) from both parents or, as is usually true of other species, from the mother alone. The genes it receives from each parent arrive at the same time—fertilization—but the parental investment may have started well before fertilization and will continue long afterward, split, as in the human case, between the two sexes in a complex, changing manner. But before we get into these complexities, why sex itself? Why bother?


Why sexual reproduction? Why not go the simple, efficient route and have females produce offspring without any male genetic contribution? Females typically do all the work; why not get all the genetic benefits? In other words, why males? There are, in fact, many all-female species, but they tend to be clustered in small animals (very small insects, mites, protozoa, and so on), with some notable exceptions, such as are found in some lizards and fish. And among those with larger body sizes, asexual species do not persist long over evolutionary time, they go extinct. Why these two facts?

The advantages of sex must come from the benefits of producing genetically variable offspring. Two human parents can—through the magic of everyday recombination—produce billions of genetically different offspring, while an asexual female is stuck with her own genome and the few mutations she can give each offspring. And why is it important to produce genetic variability? Logic and evidence strongly suggest that there are two important forces. By continually breaking up gene combinations, recombination permits genes to be evaluated in many different genetic combinations, instead of always being tethered to the same set of genes. This increases the rate at which beneficial genes can evolve. The major pressure for this, in turn, often comes from one’s parasites, which are numerous and costly, and rapidly evolve new means of attacking you. Parasites favor in their hosts both the production of genetically variable offspring and offspring with high internal genetic diversity (heterozygosity). This underlying genetic imperative of sex has important implications for mate choice and other aspects of sex, as we shall see.


Sex has been the dominant form of reproduction in most species for hundreds of millions of years. Two partly competitive morphs, males and females (defined by whether they produce sperm cells or egg cells), are caught in a stable frequency-dependent equilibrium over huge stretches of time in which the relative increase in the numbers of one sex makes the opposite sex more valuable, thus increasing its numbers, so that many species have evolved to produce the sexes in roughly equal numbers.

The two sexes, in turn, are described by their relative parental investment. Females produce expensive eggs so that the number of eggs is strictly limited by their cost. Males produce sperm so inexpensive that 100 million typically do not weigh even a gram, and a man at rest can generate that number in less than an hour. When additional investment is added, it is usually added on the female side, so that in general female parental investment exceeds that of the male. This is true even in our own species, where male parental investment is often substantial.

For many millions of generations, male deception must primarily have concerned male genetic quality, since males offered nothing but their genes. It is generally believed that female choice has repeatedly favored signs of male quality that are reliable and hard to fake—size, symmetry, bright coloration, and complex song, to name but a few. Mating with such males usually produces genetically superior offspring. Sometimes high-quality males are temporarily in short supply and females may have been selected to advertise fertility to attract one quickly.

Of course, almost every trait is capable of being advertised or hidden. I once thought bodily symmetry was so often a marker of genetic quality (in plants, insects, birds, mammals, and so on) not only because it was a good measure but also because it was impossible to mimic. But the bluegill sunfish soon taught me otherwise. Males are brightly colored on both sides of their body and typically swim back and forth displaying both sides. But some asymmetrical males always swim showing only one side, the more colorful one. There are probably few females so dull they do not notice they are watching a “single-sider,” but they still do not know how asymmetrical he is—merely that he has something to hide. Such males do not do as well as two-siders but might do even worse if they revealed both their sides.

In everyday life, the importance of this first occurred to me when I was chatting with a young student who had a remarkably attractive face, and it seemed that whenever she wanted to impress herself fully on me, she turned so that both sides were shown equally and then gave a dazzling smile. The effect was very strong. So the rest of us, unconsciously and sometimes consciously, must be altering the frequency with which the two sides are displayed, with a bias to the more attractive side and to hiding asymmetry.

I would have thought by now that scientific work would have shown a series of general differences in the sexes regarding deceit and self-deception. I would expect females to be better at seeing through males than vice versa, on grounds of social expertise and amount of time devoted to social interactions, and I would expect males to be more self-deceived than females—more opportunities for benefit through self-inflation and overconfidence. I believe that women often make a deeper study of deception in their relationships than do men—self-deception, of course, is always another matter. I will never forget the sense of vulnerability I felt when I first realized my wife of eighteen months had been catching me in a series of lies without telling me. She was building up a library of my behavior for future use. I almost felt betrayed. Being simple-minded, the first time you lie to me, I am apt to point it out to you (unless there is a dominance problem).

Whether any of my speculations here are true, I have no idea, because there is no real scientific research on this subject. There is no evidence of women’s systematic ability to spot deception better or to propagate it more deftly. Nor is there a clear bias in self-deception when comparing the two sexes—except perhaps for overconfidence, where there surely appears to be a male bias.


To explore deception and self-deception between the sexes at first contact, it is helpful to know that in humans, female choice usually focuses primarily on a male’s status, resources, and willingness to invest as well as signs of genetic quality (especially when she is ovulating). The latter may be revealed by physical attractiveness (for example, facial symmetry and facial masculinity). So we expect males to misrepresent their standing on these attributes upward. They appear to have more to give than they actually do, they are more likely to give it than in fact they will, and their genes are better than they really are (this last one perhaps is the hardest to fake).

Male choice focuses on physical evidence of fertility and fecundity—youth, waist/hip ratio (curvaceousness), breast size and symmetry, and evidence of genetic quality, as in degree of facial symmetry and femininity. Finally, males place a value on female sexual monogamy (never mind their own tendencies).

Given the large initial difference in parental investment—at its extreme, a sperm cell weighing one-trillionth of a gram and a nine-month pregnancy producing a seven-and-a-half-pound baby—it is hardly surprising that men (compared to women) place relatively greater emphasis on short-term mating relations than on long-term. This leads to a large and consistent psychological difference between the sexes regarding sex itself. Men all over the world show a greater preference for sexual variety than do women. Men desire more sexual partners over various time intervals, are more likely to consent to sex with an attractive stranger, have twice as many sexual fantasies per unit in time, and are more likely to seek out prostitutes and to lower their standards in choice of women for short-term relationships. Women more than men report being deceived about partner ambition, sincerity, kindness, and strength of feeling. Only in willingness to have sex are women seen as more deceptive than men—hardly surprising given men’s interest in sex.

Likewise, there is selection for females to simulate orgasm, but rarely a pressure (or necessity) for males to do likewise. Women fake orgasms to massage the male ego and to bring an end to unwanted sex. Some men are completely fooled, many probably at least some of the time. The real orgasm is assumed to act positively regarding sperm movement, that is, sucking it inside. It also makes future sex with the same partner more likely.

One can, in turn, measure how much either sex is upset by particular deceptions of the opposite sex. As expected, women are more upset at male overrepresentation of resources and status than vice versa. But these are minor factors. Where women really get upset is in response to two related deceptions: men misrepresenting the depth of their feelings prior to first having sex and men failing to call or contact them after sex. That these behaviors may also involve self-deception, I have no doubt. In the early’60s, when I was a young man, I was conscious of something I called “false emotion.” I would meet a woman, develop a strong attraction, wheel out my full show, feel I was in love, have sex with her two or three times, and then find the entire attraction collapsing—indeed, often turning into aversion. The false emotion of romantic love must have been generated the better to induce the sex that ended it, but I was conscious of this only after the fact. The women, of course, were bitter.


One of the most important issues for a man occurs nine months after a sexual act is said to produce a brand-new child, of which he is claimed to be the father. But is he? The difference is critical, related by ½ or related by 0. Sex all but guarantees maternity, of course, but it does not guarantee paternity. Men are expected to be especially likely to be concerned with problems of parentage, as indeed they are. How about our powers of perception? There appears to be no difference between the sexes in ability to recognize whether children are the offspring of a given parent, but both sexes more easily spot relatedness through the mother, and each is better at spotting relatedness when the baby is of their own sex. There is, however, a striking sex difference in attribution of relatedness to newborns—women and their relatives overwhelmingly comment on resemblance to the father (more so for sons than daughters) and, as expected, putative fathers may be both taken along and somewhat skeptical of the claimed resemblance. Experiments in which people’s faces are morphed onto unrelated children so as to create an artificial resemblance show that men are affected by greater self-resemblance in claiming greater willingness to adopt, pay child support, forgive after something is broken, and so on—but women are not. Many societies have jokes on the subject. In Senegal: “Better to have an ugly baby who resembles you than a good-looking one who resembles your neighbor.” In Jamaica, to give a man a “jacket” is to father a child he takes as his own. The better the jacket fits (resembles him), the happier he will be. To “cut a man a waistcoat” is to produce a perfect mimic, since waistcoats have to be individually tailored to fit properly.

How can you know for sure that the child a woman carries is genetically your own? Of course, you can’t. Some men torture themselves over the possibilities, the hours when she was not around, phone calls with old friends, whatever. But I always believed the issue was overrated, because I did not believe it was possible for me to look at a child for long and not be able (without DNA tests) to know whether it was my own. There are enough dominant genetic markers in my lineage that the truth must be there in front of my eyes. If that is really true, then we are talking at worst about nine months or so of wasted investment, a trivial cost, put to a good social purpose. Let us put the matter behind us and go on with the rest of our lives. In other words, we need not spiral off into the fatal land of jealousy, but that is alas all too common, as the following suggests.


A man’s response to signs of his partner’s infidelity in an intimate relationship seems general the world over: anger and aggression, an attempt to suppress the behavior by threatening, beating, isolating, and sometimes murdering the woman. The result often is a thoroughly frightened and dominated woman, told that any attempt to flee will be met by murder, leading to a defensive form of imposed self-deception, where the woman often comes to believe her tormentor and blames herself. Genital cutting of women (to reduce desire), foot binding (to reduce mobility), and claustration (to isolate socially) all serve to reduce female choice in advance of temptation, though I doubt they are usually rationalized this way within the societies that practice them.

The law is stacked as well. It was a historic and cross-cultural universal for “unauthorized” sexual contact with a married woman to be a crime (for both the man and the woman), with the husband as the victim. In some parts of the United States, the very sight of adultery was, until very recently, considered sufficient justification for murder—of either party—by the husband. What all this means is that extramarital sex or the mere suspicion of it can be very dangerous to the woman (and the other man). Very powerful selection pressures—murder and imprisonment, for example—may be associated with deception regarding extra-pair relations. My own (very limited) experience is that one can hardly deny from consciousness other ongoing relations, so that extra-pair relations inevitably involve conscious deception, and self-deception must at best serve self-confidence in the face of possible accusation.

Consider homicide. In many American cities, sexual jealousy is the second or third leading cause of murders, and in many societies it is the first. In Detroit, one-third of all murders in 1972 were “crime specific” (as part of a robbery, for example), but of the remaining, fully one-fifth were due to sexual jealousy. The detailed breakdown is of some interest (total N = 58). Men were four times as likely as women to instigate jealous actions leading to murder. In roughly equal numbers, men killed their partner or the other male and were almost as often killed themselves by the woman (sometimes aided by a relative of hers). Two men murdered their unfaithful homosexual lovers—no problem of uncertain paternity there! When a partner was unfaithful, women were somewhat more successful, killing one of the adulterers in nine instances while being killed by the mate in only two.

In Canada, 55 percent of all wife-beating court cases involve at least some jealousy. Men respond to possible infidelity with anger, drunkenness, threats, and sexual arousal. The last is a most interesting subtlety. In many species of more or less monogamous animals, the sight of one’s own female having sex is sexually arousing to the male. Even ducks being raped by groups of males are often re-raped by their mate immediately afterward, presumably to introduce sperm in competition with that just introduced. So it is a feature of male psychology that evidence or fantasies of mate involvement with others may be sexually arousing. I have never found the reverse to be true. Women respond to extra-pair copulations with tears, feigned indifference, and efforts to increase their attractiveness. Men get angry and drunk.

Men are, of course, prone to self-deception in evaluating their partner’s extra-pair activities. The lower their self-image, the greater their expected suspicion, if not full-blown paranoia. The lower his intrinsic quality, the greater is her temptation. Given that he is of lower putative genetic quality, she may more easily dominate him, so that he may not dare voice his suspicions for fear of being dropped entirely. A second reason men may practice self-deception arises from their own guilt. Many times I have seen men accuse their innocent partners of exactly what they themselves are up to, another case of denial and projection, the accusations presumably serving mostly as camouflage.


A woman’s biology changes in very interesting ways during her monthly cycle, with many implications for deceit and self-deception. Women are more attractive at the time of ovulation—they appear to be physically more symmetrical and their waist/hip ratio is slightly more curvaceous. They also derogate the looks of other women more than at other times in the cycle. Are they (unconsciously) comparing other women to themselves and derogating other women because they themselves are relatively more attractive when ovulating, or are they adding a degree of derogation so as to accentuate their own superior appearance when it most matters? I would imagine the latter, but the evidence is not sufficient to say.

Women appear to be more sexual in general at the time of ovulation but with a distinct bias toward more genetically attractive men and extra-pair sex. In several clubs in Vienna where partners were studied over many months, a woman was less likely to show up with her partner near her time of ovulation while displaying more skin (wearing less clothing). At time of ovulation, women’s preferences for men’s faces shift toward those that are relatively more masculine and symmetrical, signs of genetic quality but not paternal investment. (Women’s preference also shifts toward slightly darker men and less hairy ones.) If employed as a lap dancer and not on the pill, a woman earns 30 percent more per hour when ovulating than when not (excluding during menstruation, when she earns even less). If she is on the pill, then there are no differences in her earnings across the monthly cycle.

Changes across the cycle can reflect underlying subtle genetic tensions between the sexes. A particularly striking result shows that the more a woman matches her partner’s genes at critical major histocompatability loci involved in defense against parasites—which is a disadvantage in that it lowers offspring survival—the less likely a woman is to have sex at ovulation, the more often she has (verbally) coerced sex, and the more often she fantasizes about sex with another man (including prior partners) while having sex. But twelve days later, when she is not ovulating, there is no effect of gene matching on her sexual behavior and fantasies (compared with women who do not match). Men show no effects of matching their partner on the major histocompatability loci at any time. They are out of the loop.

So we expect more pressure on women to act deceptively at the time of ovulation. In this case, the woman engages in a voluntary, conscious kind of self-deception—temporary fantasy—that she is unlikely to wish to share with her partner. She may start developing a private life of fantasy that recurs each month, perhaps tempting her to more overt actions at this time in the future. In any case, a private life is carved off from her partner, acting over a few critical days every month. It would be most interesting to know whether some men notice that when their partner is most attractive to them, she is least sexually interested in them. And how do they respond, if at all?

Smell is an important part of sex. A woman’s sense of smell is more acute than a man’s, and this is especially true at her time of ovulation, where her sensitivity to certain sex-related compounds may increase a hundredfold and her ability to discriminate men’s bodily symmetry based on smell hits a peak. I am often astonished at how naive young men are regarding the olfactory dimension of life. I hear the same story from students: “I was due to meet my girlfriend later but this woman was hot for me, so I enjoyed some sex, nothing special, nothing to detract from my lady, but as soon as I saw her, it was like she knew right away something was up.” I then ask these young men whether they had thought to bathe after having sex. No, hadn’t occurred to them—perhaps this was their problem. They were living in one olfactory world, their partner in another. Of course, there may be no escape—a good student of your behavior may ask you why you just bathed at this odd time of day.

This difference in the olfactory dimension can be extended to many other aspects of mental life. Women are better at reading facial expressions, but men are better at picking out hostile images in a crowd. Sounds may be processed in different sections of the two brains, and it is a remarkable fact that in a variety of mental tasks, women’s brains tend to act more symmetrically than men’s—that is, the two hemispheres are used more equally in solving a given task. Since symmetry is so often an advantage in life and mental life in particular—for example, depth perception and location in vision and hearing both result from the use of bilateral information simultaneously—one’s initial assumption must be that women thereby gain an advantage over men. The corpus callosum connecting the brain’s two hemispheres in women is relatively larger than in men, meaning information is more easily shared and symmetrical functioning more likely.


Several lines of evidence suggest that men deceive themselves about women’s sexual interest in them. Women report that men are more likely to believe that a woman has greater sexual interest in him than she really has, rather than less. By contrast, women show no bias in how they rate men’s interest in them (high or low). Experimental evidence provides congruent evidence. By logic, men may gain more from such a perceptual bias than do women. They will catch more women with actual interest while making more false projections in the process. Assuming there is not much cost to the errors (the woman turns him down, he departs), the bias will give a net benefit. Of course, a reputation for overeagerness could add to the cost. This might result in a self-deceived bias toward greater interest while simultaneously thinking of oneself as “cool”—relatively restrained toward others.

There is evidence that women’s behavior may heighten male illusion of female interest. When in experiments the two sexes are introduced for the first time for a ten-minute videotaped session together, female courtship behavior is higher in the first minute (e.g., nodding) but unassociated with any actual interest. Such behavior is associated with interest only in the later stages (four to ten minutes), so that women appear to display interest before they develop it. This will give men the illusion of interest before it develops and, indeed, female nodding behavior in the first minute predicts male talking in the later stages.


It has long been argued that denying one’s homosexual impulses will cause one to project them onto others. It is as if we detect some homosexual content in our immediate world, and denying our own portion, we go looking for it in others. That this homosexual denial can lead to homosexual aggression is not surprising, because someone else’s homosexual content may be a direct threat to our own hidden identity—do we respond, in spite of ourselves, to an attractive young man with a bouffant hairdo and a woman’s perfume? We had better attack him before anyone notices our arousal. This is also sometimes called a reaction-formation. What is attractive to the self but unacceptable is disdained and denied for self but attacked aggressively when seen in others. A man thereby supports his image of heterosexuality by attacking homosexuals.

Recent work supports this kind of dynamic. In the United States, A-1 heterosexual men by Kinsey criteria—no homosexual behavior, no homosexual thoughts or feelings (or so they say)—were divided into those who were relatively homophobic, that is, upset and hostile toward homosexuals, and those who were relatively relaxed and unconcerned.

The fun part came when these men got to watch three six-minute erotic movies—a man and a woman making love, two women, and two men—while a plethysmograph attached to the base of each penis measured penile circumference very precisely. In addition, after the film, each man was asked how erect and how sexually aroused he had been. An interesting result emerged. Relatively homophobic and non-homophobic men responded similarly to the heterosexual and lesbian films, strong arousal to each, but more so for the heterosexual. It was only the male homosexual film that revealed a divergence. Non-homophobic men showed a small but insignificant increase in penis size, but homophobic men showed steady penis size growth throughout, reaching two-thirds the level seen in their response to the two women. Interviews afterward showed that everyone had an accurate view of the degree of his penile enlargement and arousal (which were highly correlated), except for the homophobic men viewing the male-homosexual scenario. They denied their tumescence and arousal. Whether they were actually conscious of this is unknown.


There are two extreme forms of deception in a relationship where sex and love are concerned. The sex is great and you have to fake the love, or the love is real but you have to fake the sex. By the time we are thirty, we have all been in these situations. When we have to fake the sex, we often invoke fantasy, a prior partner, an imagined partner, an imagined sexual act. Whatever gets us off. Note that these relations are especially dangerous to the partner. If the partner is unaware of your own true reactions, he or she will be unprepared for the betrayal that so likely awaits. On the other side, it may be much harder to fake love when there is strong sexual interest. Low-love relationships are apt to be more volatile, open hostility coexisting with passionate sex.

The simple answer to the question about the effect of self-deception in a marriage is that it depends on the kind of self-deception. Self-deception of a positive, couple-reinforcing form appears to be beneficial, while self-deception associated with resolution of one’s own cognitive dissonance in the conventional self-serving ways appears to have the opposite effect—over-affirmation versus distancing. The aphorism that you should go into marriage with both eyes open and, once in it, keep one eye shut captures part of the reality. When you are deciding whether to commit, weigh costs and benefits equally; when you have committed, try to be positive and not dwell on every little negative detail.

Consider first the positive form of self-deception. Couples last longer if they tend to overrate each other compared to the other’s self-evaluation. This has an appealingly romantic ring—“I love you, darling, more than you love yourself, and thereby uplift you.” Effects work on both sides. The more you overrate the other, the longer you stay together, and vice versa. Assuming long life together is a benefit, over-valuation is beneficial.

People have a bias toward seeing improvement in the relationship over time even if this is achieved by exaggerating how bad the past was (compared to evaluations of the present). Once the past is misremembered, the memory of progress is established and relationships with greater memories of improvement last longer. It is important to emphasize that we can’t discriminate cause and effect. Self-deception may improve relationship satisfaction and duration, or it may accompany other factors that do. Perhaps success breeds self-deception (of the positive sort).

Evidence suggests that marital satisfaction declines linearly over time, but people have a biased memory—they remember early declines in satisfaction but more recent increases that offset the early decreases. In one study, both spouses reported steady increases in relationship satisfaction over two and a half years while none could be detected. By the end of the time, though, memories were readjusted so as to remember no improvement in the more distant past, only in the more recent.

In contrast, processes of self-justification within individuals make unity between the two more difficult so that, in the extreme, self-justification may be seen as an “assassin” of marriage. That is, active processes of self-justification appear to work against marital unity in a major way. Again, we do not know cause and effect. Is self-deception causing the disruption, or only facilitating it?

What we do know is that patterns of self-justification can be diagnostic. In trying to predict which couples would stay together three years later, scientists enjoyed surprising success based on studying the interaction between the two people during recorded sessions. Those who rewrote history in a more thoroughly negative way were predicted to break up. On this basis alone, the scientists correctly predicted all seven marital breakups, while incorrectly predicting three breakups that did not occur. They correctly predicted the other forty non-breakups, for a remarkable overall correct prediction rate of 94 percent. Though none discussed separation, some couples already talked as if they had forgotten why they married in the first place and were deep into processes of self-justification that appeared to function to reduce the dissonance of being in a bad marriage (while, of course, doing nothing to repair it). Other students of marriage claim to notice that when the ratio of positive to negative acts toward the partner drops below 5:1, the marriage is in trouble.


Fantasy is an inviting and treacherous activity. It is deeply rooted in our biology. From our earliest years, we practice it spontaneously, with great pleasure, and it is easily encouraged by others. We create an artificial world and then choose to live in it. The fantasy typically replaces reality in a positive way—things would be better if the fantasy were true. For example, our five years of 24/7 work in the laboratory is, in fact, Nobel-quality work. As we do it, we can enjoy the return benefits sure to come our way later. Short of inducing fraud on our part, the fantasy may, in fact, improve the quality of our work. What the actual trade-off in additional fantasy-fueled labor and output is really worth, measured in other lost opportunities, is another matter, especially as the fantasy fails to pan out.

And what about the downside? Consider a romantic fantasy. That woman far away is, in fact, your wife-to-be, if not (in full delusional mode) your very soul mate. Now you can pour it on full time in the lab, certain that your romance and (future) sexual life are taken care of. You may send a portion of your earnings to your beloved every week and tell her that since you cannot show your love to her more directly, you take joy in showing it by sending her money. She will be pleased. She will be so pleased she may encourage you in your fantasy. In fact, she may have created it almost single-handedly in the first place.

Jamaicans have a term for this form of manipulation, called having a “boops.” A boops is typically an older man who supports a young woman—her rent, electricity bill, runaround expenses, perhaps a small car—while receiving minimal sexual favors in return, only the fantasy of what soon will be his. In the optimal case, he receives no sex at all—the more fevered to keep his imagination and the more rewarding his behavior. Once caught up in his fantasy, he hardly wishes to question it. Contrary evidence that in other situations would put you immediately on guard or at least warrant some study is easily brushed aside (say, failure to receive any Christmas present at all while lavishing major ones on her). As one psychiatrist put it, “You do not want little, niggling details of reality to interfere with a good fantasy.”

Now that someone else is driving your fantasy, it may carry you far from your true interests. Yes, you do wonderful lab work for six months, but if you have really bought into your fantasy, you are suffering numerous immediate costs and must someday suffer a painful de-fantasization in order to reconnect yourself with your actual interests. There can be no doubt that sexual and romantic fantasies, unfulfilled, must rank as among the most costly. Not only is a greater portion of your potential reproductive success on the line, but so is your vulnerability.


If deceit and self-deception in the family have the deepest effects on one’s life, then those concerning sex are the most painful. There is nothing like sexual betrayal for pure pain—nothing like learning a loved partner is betraying you left, right, and center to split your soul in two. Deception and self-deception coming from early family life may be associated with pain akin to chronic arthritis, but with sexual betrayal, the pain is more like being hit by a truck. I believe this is true for both sexes.

There are at least three elements to this. First, the reversal in fortune can be very large—a child assumed to be your own is not, a life of love assumed to be two-sided goes in one direction only. Second, the (so-called) betrayal often rests on a bed of lies, of willful deception that may have gone on for months or years. You have played your part in all of this, by believing the lies—often with active self-deception or at the very least with failure to show due diligence.

Finally, the deceptions reach in all directions. Many lies in life are largely between you and the liar. Sexual lies inevitably encompass others, sometimes dozens of others who know a side of your life that you do not, increasing the degree of public shame. For a truly extreme example, consider the dreadful case of Elin Woods, who had to endure the knowledge that her husband, Tiger, had sex regularly with a waitress who worked across the street—at a diner they frequented—seduced the daughter of a next-door neighbor, a family she had known for several years, employed numerous people to hide his sexual life who also interacted directly with her, and then—to top it all off—let a billion people in on the secret. Arnold Schwarzenegger has now pulled off his own stunt along these lines, also available for full public enjoyment.

Why is sex so often associated with shame? One reason is that sexual activity often acts against self-interest directly—the damaged self. This includes, in principle, masturbation, bestiality, homosexuality—all sexual behavior that fails to benefit self. Unrelated individuals will have no direct self-interest but relatives will—their self-interest is directly harmed by your sexual misbehavior, as may be their reputation. So they may feel special pressure to shame you.

In principle, your inappropriate sexual behavior can upset many individuals.

Again the contrast with the family offers insight. We could have grown up under complete subjugation while being sold an ideology of equality, but usually we fall somewhere along a continuum of relative domination and misrepresentation. But infidelity (like pregnancy) is not spread along a continuum. You either are unfaithful or you are not—pregnant or not. The reversal of fortune is often absolute.

Perhaps you say to yourself, “What’s the appropriate reward for someone who has lied to me, disrespected me, and plundered from me for two years?” and strangulation comes to mind. But should you not strangle yourself as well? Every deception was received and ignored by you. Your own self-deception was manipulated against you, probably both consciously and unconsciously by your partner. The two of you made that bed and lay in it.

There is often some kind of relationship between the family situation you grew up in and the one you find yourself in. Surely some of the resemblance is both genetic and through imitation. But there are also logically related effects of a different kind. Chris Rock, the American comedian, likes to joke that every woman has “a daddy problem” and you, her current partner, have to pay the price. Imagine dating a woman and taking her one day from an abusive relationship with her father. At first she will be happy, but with any hint that a man strong enough to do that could dominate her worse than her father in other ways, you have a problem on your hands.

Sexually induced pain is presumably greater the more intimate a couple have been—probably independent of the chance of propagation. Why? Imagine a sex life of relatively modest physical commitment—an embrace, a few kisses, the man climbs on top, and the two enjoy a good copulation. Contrast this with lovemaking that involves the intimate exploration of and numerous loving acts toward the body of the other person, and vice versa. After betrayal, the second is the much more painful of the two, loss in the pleasure of intimacy being the greater and also suggesting greater long-term love lost. And the greater intimacy is more painful to your imagination on both sides—he now has done those things with someone else, giving you a stabbing pain, and you also did such-and-such with him and he has gone elsewhere.

There is little doubt that pain from a relationship is among the worst of pains. With physical pain, you can almost always do something to ease it, but with emotional pain, you have to wait until it eases itself. The pain is felt on the inside and the outside—there is a social dimension that only adds to the personal. Remember that betrayal often links your partner to a web of lies involving many others—people who knew but did not speak, and so on.

Another very painful part of the interaction is that when evidence suggests that a long-term relationship is hopeless, the best strategy may be to cut the relationship in half, discard the other person, and minimize interactions, but this in itself is very painful, as if you are cutting yourself in two. Grown up between the two of you may be multiple lines of communication, now severed, so that you suffer extreme social deprivation. Two or three phone calls a day give way to oppressive silence. The sharing of joys, of minor insights, of hopes and fears, all fall by the wayside. The desire to reestablish contact—even hostile contact—is almost overwhelming. You find yourself talking to the person, and not usually in a nice way, either. If you engage in spiteful behavior or fantasize about payback time, you risk being caught in a passionate embrace, not warm but passionate, time-consuming, painful, costly, and negative.

We now have come full circle, from some of the most tender, loving, and physically exciting moments in our lives to some of the bitterest memories, as victims of lies, treachery, and even public shaming. From love to murderous impulses. This transformation is not created by self-deception but is fed by it at every stage.