Decoding Love Page 5

  Trivers’s brilliant insight was to realize the enormous ramifications of this simple difference. For a man, the ideal approach from an evolutionary standpoint—passing along his genes to as many children as possible—is to sleep with as many women as possible. And he shouldn’t worry too much about the quality of those women. Ugly women, pretty women, women with no teeth, women who can’t spell unilateral—it doesn’t matter. Having sex with them costs him very little effort, and all of them provide an opportunity to pass along his DNA. For a woman, though, the ideal approach is to be as selective as possible. With so few opportunities in a lifetime, she wants to ensure that she gets quality genetic material from the father. So, for her, it makes a great deal of difference whether the father is a bright, attractive, funny guy who likes to read Jane Austen or a slack-jawed, humor-less oaf who mistreats his dog. Hence, the battle of the sexes—a constant war between men who want to seduce with as little work as possible and women who want to resist until they are sure that the potential father is genetically superior and committed to help. As one research team writes, evolution favors males who are “aggressive sexual advertisers” and females who are “coy, comparison shoppers.”

  Ah, but wait! We have left out one crucial wrinkle: pair-bonding. In our case, the legal bond between man and wife, which changes the calculus considerably. With marriage, a man is tied to a woman for life. With divorce rates running at almost 50 percent, this isn’t really the case, but for theoretical purposes we’ll take the “until death do us part” seriously. So what happens to our Lothario under those conditions? It turns out that men become much more choosy as well—at least when it comes to long-term relationships (for short-term ones, most men are still pretty much willing to sleep with anyone). But that doesn’t undo all the evolutionary hardwiring related to the sperm and the egg. Even with the legal bond of marriage, men and women still find ample scope to express their natural inclinations: men as the promiscuous sperm producers and women as the precious egg holders. What this means is that conflict is built into the relationship between men and women, and pair-bonding is our attempt to contain that conflict.

  Of course, Trivers’s theory should come as welcome news to any women currently on the dating scene, because it means that women are firmly in control when it comes to the courtship phase of mating. Harvard anthropologist Irven Devore has even called males “a vast breeding experiment run by women.” This goes a long way toward explaining why men (particularly low-status males) have a lower life expectancy—they have to take more risks in order to pass along their genes. Women are probably reading this and thinking to themselves that all this Darwinian theorizing is great, but they don’t feel like they have much control at all. And it’s true that there are some mitigating factors. Because marriage at least theoretically implies a lifetime commitment, men are also choosy. In addition, demographics and culture can undermine female ascendancy. If women vastly outnumber men, for example, men become the scarce and precious commodity. So, in order to see the underlying control that women exert, I ask you to imagine a simple way that women could change the rules of American dating and marriage: they could refuse to have sex until they were married. No more one-night stands or even any long-term cohabitations. If this happened, all female complaints about men refusing to commit would instantly disappear. While many men are happy to date a woman for years at a time if they can still have sex, they would not be willing to do so if those relationships remained entirely chaste.

  WHAT HAPPENS WHEN CHEAP SPERM ARE ON THE PROWL

  Since Trivers’s revolutionary essay, study after study has demonstrated the significance of the sperm/egg distinction for human behavior (and all other creatures for that matter). Let’s start with sex. Given Trivers’s theory, you would expect to find extremely different attitudes about sex, and that is exactly what researchers have discovered. For any squeamish women reading this book who would like to believe that men are not the appalling sexual predators that they sometimes appear to be, I suggest that you skip the next few pages.

  Simply put, men have a much lower threshold for having sex. If you don’t believe me, let’s try a little experiment. If you are an attractive woman, walk up to a man on the street and ask him if he wants to have sex with you. Chances are he will say yes. How do I know? Researchers conducted a study of exactly this question. An attractive woman approached a man on a college campus and asked him one of three questions:

  1. Would you go out on a date tonight?

  2. Would you go back to my apartment with me?

  3. Would you have sex with me?

  Fifty percent of the men said they would go out on a date that night, which might seem somewhat low given what I have just said about parental investment theory. But remember that a date takes a certain amount of time and money with no promise of any sexual activity. Notice what happens to the numbers for the next two questions. Sixty-nine percent of men were willing to go back to the woman’s apartment, and a whopping 75 percent were willing to have sex with the woman (and that last number is probably low—the study noted that men who declined to sleep with the woman were usually apologetic and would often ask for a rain check or offer a reason, such as having a fiancée). Researchers then had an attractive man approach women and ask them the same three questions. When it comes to a date, women are the same as the men, accepting 50 percent of the time. From there, though, the disparity could not be starker. Only 6 percent of women were willing to go back to the man’s apartment, and not a single woman was willing to have sex with the man.

  I know some of the women reading this book are already thinking that the study isn’t valid because there is a fear factor for women accepting invitations from strangers that men don’t have to worry about. Well, the researchers realized the same thing and conducted a second study. This time, the men and women were contacted by a close personal friend who vouched for the stranger’s character. Then the friends asked one of two questions:

  1. Will you go on a date with the stranger?

  2. Will you go to bed with the stranger?

  Under this scenario, 91 percent of women and 96 percent of men were willing to go on a date—again fairly similar. But only 5 percent of women were willing to sleep with the stranger, while fully half of the men were willing to do precisely that (sight unseen!). All of this is exactly what evolutionary theory would predict. If women are choosier in general, they should be particularly choosy when it comes to a one-night stand.

  A whole slew of different statistics confirms this sexual difference between men and women. According to a University of Chicago survey, 54 percent of men think about sex once a day, while only 19 percent of women do, and 40 percent of men masturbate once a week, while only 10 percent of women do. According to another study, 85 percent of twenty- to thirty-year-old men think about sex every fifty-two seconds (which makes you wonder how men manage to accomplish anything), while women think about it once a day unless they are ovulating, when that number rises to three or four times a day. The numbers vary from study to study, but in every single one men think about sex much more than women do.

  Men also show a much stronger desire for sexual variety. In one study, college students were asked how many sexual partners they would like to have over various time intervals. Over the next year, women said they would prefer on average to have one sexual partner, while men wanted six. Over three years, women wanted two sexual partners, compared to ten for men. And over a lifetime, the average woman wanted four or five, while the average man wanted eighteen.

  This desire for variety is so extreme in men that it can lead to some bizarre behavior. In 1995, Hugh Grant was dating super-model Elizabeth Hurley, and he still felt the need to solicit oral sex with a prostitute, although his subsequent arrest had no effect on his film career (which suggests that most Hollywood moguls must have an instinctive sympathy for the occasional need to solicit a blow job). There are countless recent examples of men, ranging from Bill Clinton to Eliot Spitzer, taking mi
nd-boggling risks for sexual variety that are almost impossible to explain according to any sort of rational calculation. I think only evolutionary psychology has a satisfying answer, which is that some deep, instinctual drive created by thousands of generations of evolution—in this case, a man’s greater desire for sexual variety—was guiding their behavior. Even the clichéd idea of a man’s midlife crisis is an expression of this evolutionary urge. According to new research, a man suffers from a midlife crisis not because he is getting older but because his wife is. By coming to the end of her reproductive life, she ignites a deep-seated desire in him to attract a younger, reproductively active woman.

  Perhaps the best indicator of differences in attitudes toward sex comes from a study of sexual fantasies by Donald Symons and Bruce Ellis, which explored what each sex dreamed about when they were freed from the usual societal constraints. Both men and women reported having and enjoying fantasies about sex, but the content of those fantasies was completely different. Men fantasized much more often and were much more explicit and more visual in their fantasies. Women, on the other hand, were more likely to include context and feelings, and they experienced emotional arousal (men’s fantasies turned more on physical arousal). The women’s fantasies were also more likely to contain affection and commitment. Perhaps the starkest difference, though, was in how they imagined their partners in the fantasies. Women were much more likely to include a familiar partner, and when it came to the number of different partners, men left women in the dust. Thirty-seven percent of the men reported that they had fantasized about more than one hundred different people, a threshold achieved by only 8 percent of women. A good proxy of these differences can be found in the kind of erotica that both sexes choose. Pornography—with its explicit visual content and large number of women to choose from—is almost entirely directed at men. Romance novels—with their emphasis on emotional connections and on the relationship between one man and one woman—are almost entirely directed at women.

  SEX ON THE BRAIN

  It’s not just that men have a much greater willingness to have sex or that they seek a much wider variety of sexual partners. Their minds are also biased to perceive sexual interest from women when there may in fact be none. One of my favorite headlines from The Onion is, “Area Man Going to Go Ahead and Consider That a Date.” Any woman who has had a friendly conversation with a man only to have that man later accuse her of leading him on will know what The Onion is talking about. In a number of studies, men consistently interpreted actions on the part of women (such as smiling) as an indication of sexual interest. You can find this quick trigger interpretation even in mundane encounters. In another study, men and women listened to various taped conversations. Some of them were erotic, but many of them were routine. Although nearly all the participants became aroused during the erotic conversations, some of the men also became aroused during the regular conversations. And not only did they become aroused—their response was stronger than the female response to the erotic conversations. It’s enough to make a woman hesitant to offer up a neutral hello in conversation, for fear of sending men into a sexual frenzy.

  With this in mind, women should keep a wary eye on their male friends. Remember the debate from When Harry Met Sally about whether or not men and women could be friends? Well, science has likely found an answer—they can’t. Or at least men can’t. According to the work of evolutionary psychologist April Bleske, men are twice as sexually attracted to their opposite-sex friends as women, and they consider potential sexual encounters with opposite-sex friends as 100 percent more beneficial. They also overestimate how attracted their female friends are to them. Again, this bias makes perfect sense from a Darwinian perspective. The male brain is not designed to maximize accuracy but to maximize mating opportunities. It’s in the man’s evolutionary self-interest to see more sexual interest than may actually be there. The downside is only social embarrassment. The upside is the possibility of another opportunity to pass along his genes. In this case, the male bias is not a design flaw but a distinct advantage. In fact, the more intelligent the man, the more likely he is to exhibit what one researcher has called the “she wants me” bias. In one study, men were asked to predict how women would respond to a personal ad soliciting no-strings-attached sex. The most intelligent men wildly overestimated how interested women would be. Revealing again how women are wired in fundamentally different ways than men, the most intelligent women show a very different sort of bias—they assume that a man will be far more distressed by a partner’s sexual affair than is actually the case.

  PROMISCUITY, THY NAME IS MAN . . . AND WOMAN

  Of course, these fundamentally different attitudes toward sex set the stage for an enormous amount of conflict. Given men’s desire for a greater number of sexual partners and a social system built around marriage and monogamy, you would expect a fair amount of infidelity, and that’s exactly what we do find. David Buss, a leading researcher of evolutionary psychology, has estimated that 30-50 percent of American men have at least one affair over the course of their marriage. Even worse, it does not appear that the state of a man’s marriage has much to do with whether or not he is unfaithful. According to a survey, 56 percent of men involved in an affair still described their marriage as “very happy,” which is probably the most distressing marital statistic I have ever come across. Before women storm off in a huff and decide to foreswear men altogether, though, they should know that they lag only slightly behind men. Buss estimates that 20- 40 percent of American women will also have one affair during their marriage. Another researcher has estimated that the chances of at least one partner being unfaithful may be as high as 76 percent! As you can see, the estimates for the actual amount of adultery vary widely. Apparently, we not only like to cheat on one another, we also like to cheat on studies about adultery.

  Women’s affairs do differ from men’s. According to another survey, most women who had affairs said that they were “very unhappy” in their marriages. Women were also much more likely to form emotional commitments. While 44 percent of the men in one study claimed that they had little or no emotional involvement with their affair partner, only 11 percent of women felt no emotional investment.

  These affairs are not simply matters of the bedroom but matters of the birthing room as well. Using a number of studies, scientists have estimated that roughly 10 percent of children are not fathered by their legal father. For obvious reasons, this question has not been studied in any systematic way, and other studies have produced numbers ranging from 5-30 percent. All of this has led one researcher to claim that adultery has been grossly underemphasized as a factor in human evolution.

  Of course, when compared to the animal kingdom, we aren’t doing too badly because studies have revealed that even in the wild there is a great deal more cheating going on than anyone had imagined. Very few mammals are monogamous. One type of ape, the gibbon, was thought to be monogamous, but once scientists developed DNA testing, they found that gibbons also cheated on their partners. Many bird species form couples, which were once held up for admiration as exemplars of lifelong monogamy, but further research has shot down that heartwarming story. After using DNA testing for the birds, researchers discovered that roughly 30 percent of the offspring were not sired by the ostensible “father.” In some bird species, the number of offspring who were not sired by the “lifelong partner” reached as high as 76 percent. Even birds apparently covet thy neighbor’s wife. Scientists now believe that monogamy among birds is not due to any sort of romantic bond but is the result of the male’s attempt (often futile) to protect his paternity rights by guarding the female.

  These paternity numbers came as a shock to most researchers. Although scientists have long thought that males are eager to spread their seed, they assumed that the role of the female was almost entirely passive. One researcher even claimed that copulation was “essentially a service or favor that women render to men.” The fact that females (including women) were also
promiscuous came as a major revelation (that this was a revelation says a great deal about the power of our cultural biases to shape our thinking). We know why men are interested in multiplying sexual partners. Think back to the sperm and the egg. Sperm is cheap, and sleeping around increases the chances that the man can pass along his genes. But why are women also sleeping around? The egg is the precious resource, and the number of children a woman can produce is relatively small.