Sex, Murder, and the Meaning of Life (10 page)

The same holds for human behaviors—natural does not mean good. Here are some things that evolutionary psychologists claim are natural: men's tendency to commit more homicides than women, women's inclination to be more unfaithful while they are ovulating, and, as I just discussed, prejudice against members of completely innocent people from Harlem or Sri Lanka triggered by fear or concern over disease. If there is a moral case for these behaviors, I have never heard it coming from an evolutionary psychologist. But they would claim that these behaviors are the result of natural processes, just like maternal love, the inclination to share, and a concern for justice. Thinking about the ways in which we are naturally nice demonstrates that evolutionary analyses do not lead to an especially negative view of human nature, just to a neutral view.

If you want to live in a nicer world, you need good, unbiased science to tell you about the actual wellsprings of human behavior. You do not need a viewpoint that sounds comforting but is wrong, because that could lead you to create ineffective interventions. The question is not what sounds good to us but what actually causes humans to do the things they do.

As it turns out, some of the findings coming out of evolutionary psychology labs suggest grounds for optimism. Babies are not born
knowing whom to regard as their enemies; they have to learn whom to associate with fear. In our research on angry faces, for example, we found that American students were not especially likely to associate Asian faces with threat. In fact, white people continue to homogenize Asian men when they are expressing an angry expression.

As Rob Kurzban, Leda Cosmides, and John Tooby have noted, our ancestors were very unlikely ever to come in contact with members of other races. Instead, they came into conflict with people living in the village just down the river—people who probably looked a lot like they did. In a very interesting study, Kurzban and his colleagues showed students a highly competitive basketball game in which opposing teams wore different-colored shirts. The observers never confused men and women with one another, but they did mix up black and white players if they happened to be on the same team. So it looks as if race is fairly easy to erase from people's minds. We saw that dynamic at work during the 2008 presidential election, when Republicans and Democrats alike were more likely to think of Joe Biden as a member of Barack Obama's tribe than of John McCain's.

So the bottom line is this: Not only can an evolutionary perspective help us understand why humans are so universally inclined to feel prejudice toward members of other groups, but it can also help us understand the factors that make the strength of those inclinations go up and go down. If you happen to believe that intergroup prejudice is a bad thing and hope to discover how to reduce it, as most psychologists do, then you should not close your mind to the actual underlying mechanisms. One could certainly ask whether the academics who wrongly accused a group of left-leaning evolutionary theorists of being similar to Nazis were especially sensitive, but don't get me started.

Instead, let me close this discussion on a more optimistic note. In thinking about evolution and prejudice, my colleague Mark Schaller likes to toss around a pair of quotations from Barbara Kingsolver
(who was a graduate student in evolutionary biology before she became a novelist):

So far, we have been hanging out in the gutter, talking about sex, aggression, and prejudice. Now we will shift our gaze higher, considering how the findings of evolutionary psychology reflect on two profoundly important philosophical questions about human nature and how the mind works. But if you prefer pondering the many puzzling aspects of sex and aggression to an abstract philosophical treatise, don't turn that dial yet. We will consider the question of human nature and the mind in light of some very interesting findings on male-female relationships—in this case, romantic affairs between younger women and older men. For decades, social scientists thought the phenomenon was a simple and obvious outgrowth of American culture. But the real reason turned out to be neither simple nor obvious. In fact, uncovering the root cause of men's and women's age preferences has involved something of a scientific mystery story, complete with a search for clues that took my colleagues and I around the world, and with bad police who wanted to halt the investigation.

B
ozeman, Montana, 1977. I'm a brand new assistant professor at Montana State University, land of
Zen and the Art of Motorcycle Maintenance
, where the snow-capped Bridger Mountains are visible from campus. I've just given a lecture to a faculty group about my research on human mate preferences, and it's the questionand-answer period. An anthropology professor in the audience is addressing me with a rather stern tone in her voice. Like many academics, she has acquired the peculiar custom of stating her “questions” in the form of lectures. These lectures-disguised-as-questions are usually delivered in a haughty and didactic tone, meant to set the speaker straight on some topic about which the questioner fancies himself or herself more expert.

In my talk, I had made a generalization about human mating strategies, which triggered a minisermon about the range of cross-cultural variations in human mating. The anthropologist seems quite adamant in her conviction that, as a psychologist who conducts laboratory experiments with a narrow sample of American college students, I have absolutely no justification for making any sweeping generalizations about humans as a species. When one looks across cultures, I am admonished, one finds an unlimited variety of male-female relationships. In other words, she is explaining why and how
anthropological research has proven that the mind is a blank slate. But has it really? Some research I conducted on dirty old men's preferences for younger women has made me increasingly dubious of this claim.

A few years after I left Montana State, I gave a lecture about interpersonal attraction to a singles' group in Phoenix, Arizona, and one of the older women in the group asked me why it was that men in her age group all seemed to be prowling around for “young chicks.” The other older women all chimed in with their agreement, and as evidence, they handed me a pile of singles' newspapers. Many of the ads were written by men who listed their own age as being in the forties or fifties but who were seeking relationships with much younger women.

I lugged the newspapers home and showed them to my longtime friend and colleague Rich Keefe. Rich had been in graduate school with me at ASU, where we had studied how to apply behavioral learning principles to clinical psychology. Like me, Rich had come to believe that psychology needed to be updated by evolutionary thinking. We began to look at the ads to see if the women's complaints held up, and if so, to ask what evolution could tell us about it.

Several social scientists had previously analyzed data from singles' advertisements and had noted that women, on average, sought men a few years older than themselves and that men sought women a few years younger than themselves. This was one of the few known exceptions to a social-psychological law called the similarity-attraction principle—the general tendency for people to desire friends and romantic partners who are carbon copies of themselves. For example, liberal, Jewish, nonsmoking mountain-bikers are usually seeking a partner with the same interests and attributes rather than hoping to expand their horizons by dating conservative, Baptist, chain-smoking
Harley riders. Earlier researchers expected that the same rule would hold for age preferences, that older men and women should prefer older partners.

When they discovered that age preferences violated the similarity rule, the researchers blamed American cultural norms for the discrepancy. For instance, sociologist Harriet Presser suggested that there was a “norm” that “a husband should be, or at least appear to be, mentally and physically superior to his wife. Not only should he be taller than she (for the appearance of superiority) but also older (which gives him the advantage of more time to become better educated and more experienced).” Along similar lines, psychologist Leticia Anne Peplau and sociologist Steven Gordon put it this way: “American culture encourages sex-linked asymmetries in the characteristics of dating and marriages” in which, for example, “women are traditionally taught to seek a man who is taller, older . . . more occupationally successful.”

Around the same period, Julie Connelly published an article in
Fortune
magazine in which she used the term “trophy wives” to refer to attractive younger women who were the second wives of older, powerful American executives. When social scientists were called on to explain the phenomenon, they ascribed it to something about modern American culture. One sociologist, for example, attributed the trophy wife syndrome to cultural images in the media, which depicted the ideal man as a successful businessman in his late forties or fifties, and the ideal woman as an ingenue in her twenties or early thirties.

Keefe and I seriously doubted that the older man–younger woman phenomenon was really a product of American cultural norms or modern media images. We thought instead that it could be explained in light of a couple of universal biological differences between women
and men. First, women undergo menopause, a complete cessation of fertility, during their forties. Men do not. On the other hand, women are highly fertile during their twenties, and the features men find attractive in women, such as rounded hips, full breasts, and lustrous hair, are indirect cues to that fertility. A strong innate bias for those fertility cues would easily account for the older men's preference for younger women. On the other side, we suspected that women are seeking men who could contribute indirectly to their children by providing food, protection, and other resources. To the extent that men continue to accumulate resources and social status with age, women would be expected to prefer older men.

Our theory did more than just reexplain the existing findings; it had new and testable implications. If we were right, and men were seeking fertility, then the preference for younger women would be very strong only in older men, not in very young men (because for men in their late teens and twenties, their age mates are highly fertile). But to test our ideas, we had to look at age preferences in a different way. Earlier researchers had simply clumped together advertisers of all ages and reported an average age discrepancy for each sex. We instead separated the advertisers into age categories, and this revealed a pattern more complex than men wanting slightly younger women and women wanting slightly older men. Indeed, the pattern Keefe and I discovered fundamentally contradicted the standard social science explanations of why men and women act like they do.

Women's preferences were not the problem: Keefe and I found that women were acting just as earlier researchers had described. Women were looking for somewhat older men, and this general pattern persisted throughout their lives. We were actually surprised to find that the preference for slightly older men even persisted among women in their sixties, when there are a lot fewer older men to choose from.

The men's preferences, however, shifted dramatically according to the age of the guys. The youngest men, despite the supposed societal
expectation that they should look for younger women to dominate, were instead interested in a range of women. A typical guy of twenty-five was interested in women as young as twenty and as old as thirty. In a later study, we found that teenage boys were most attracted to women slightly older than themselves—college-age women. Teenage boys expressed this preference even though they realized the older women were unlikely to reciprocate their interest. But as men aged, this preference for partners their own age progressively shifted to an interest in women younger and younger than themselves. A typical forty-five-year-old guy wanted nothing to do with women his own age; instead, his preferences ran to women five to fifteen years younger. And men of fifty-five were even more extreme in their desire for younger women. In this sample from the late 1980s, men who came of age listening to Elvis Presley were eying the girls on their way to U2 concerts, while the women of the same rockabilly generation were hoping to woo a codger from the Frank Sinatra era.

As one critic suggested, the singles' ads might represent nothing more than fantasy. Who cares what people say, the argument went; whom do they actually pair up with? Maybe the president of the Acme Widget Corporation can attract a younger woman, but the average Joe down on the receiving dock can only dream. So Keefe and I collected a random sample of marriages from Phoenix, the city from which I had gotten the first samples of singles' ads. In a pattern exactly matched to the singles' ads, age discrepancies between men and the women they married got bigger with the man's age. Younger men married women near their own age, and a reasonable number of young men married women slightly older than themselves. Older men married women increasingly younger than themselves—just like the rich and powerful CEOs of Fortune 500 corporations.

Stated simply, then, our findings suggested that people's apparent age preferences are not ultimately about age at all. Because women contribute their own bodily resources to the offspring, men are seeking
cues linked to fertility and health. Because men contribute indirect resources to the offspring, women are seeking cues linked to the ability to acquire those resources. Men's resource acquisition and women's fertility are correlated with age, but age itself is not the driving force.