Sex, Murder, and the Meaning of Life (11 page)

To someone with any background in evolutionary biology at all, our explanation might sound self-evident. But at the time, most social scientists did not think much about a link between human courtship and reproduction. And when we started talking about our findings in these evolutionary terms, we were often met with derisive sneers and claims that our account was obviously wrong, along with arguments that our findings could be explained in terms of the “norms of American culture.”

Of course, there are norms in American society indicating that it is less typical and appropriate for a woman to pair off with a younger man than with an older man. But even if a behavior is consistent with a norm, that is no proof that the norm caused it. Sometimes a norm is prescriptive (Thou shalt not marry someone under the age of consent, for example), sometimes a norm is simply descriptive (men fantasize about sex more frequently than women do, but not necessarily because they were told they had to do so).

It is easy to generate alternative explanations for almost any phenomenon. The trick is finding evidence that reflects on those opinions. In the remainder of this chapter, I will describe our search for further evidence that could distinguish between the normative and evolutionary explanations for sex differences in age preferences, as well as a few surprises that we discovered along the way.

The data we had found so far was interesting but insufficient to dismiss the possibility that all modern Americans, teenage boys as well as aging CEOs, are influenced by exposure to similar cultural norms
and that the mass media were the vehicles for disseminating those norms. One way to address the “modern media” hypothesis was to examine marriage data from before the advent of television. To that end, we examined data from Phoenix marriages for the 1920s. Television was invented during the 1920s but was not commercially available until the 1940s, and fewer than 1 percent of homes had a television before 1950. The first TV station in Arizona was not even licensed until 1949. But Keefe and I found that marriage patterns were the same in the good old days, long before Ricky Ricardo fell in love with Lucy. Indeed, the pattern from the tubeless '20s matched perfectly with the one we had found in all the data from the 1980s, including the CEO marriages.

It was still possible, though, that the phenomenon might be linked to a different element of American culture, something that predated the modern media age—materialism perhaps, or individualism, or any of a host of other features of American society. To determine whether some common American cultural element underlies this pattern of behavior, we began to examine similar data from other societies. Our colleague Guus Van Heck from the University of Tilburg sent us data from singles' ads in newspapers in the Netherlands, and Ute Hoffman and Kirstin Schaefer of the University of Bielefeld sent us the numbers from singles' ads in Germany. In both cases, the data revealed the same sex-differentiated pattern we had seen in the United States. And the pattern was again not limited to Euro singles' fantasies or to the modern media age; Sarynina Nieuweboer uncovered the same pattern in actual marriages in Amsterdam from the seventeenth, eighteenth, and nineteenth centuries.

But it was still possible to argue that the Netherlands, Germany, and the United States all have European-based cultures and might therefore be subject to many of the same normative pressures. We were fairly confident that this was not a limited cultural pattern, but we needed to prove it. So we looked next at several non-European
societies. We began with marital advertisements from Indian newspapers, which my colleague Steve West first brought to our attention. The Indian marital ads indeed painted a picture of a very different society, with very different cultural norms about marriage. The ads were commonly placed by family members acting on behalf of the unmarried individual, and the ads specified characteristics related to caste, subcaste, and subdenomination of the Hindu or Muslim faith. They also typically requested horoscope information. For example, one ad placed in Bombay's
Times of India
stated:

Despite the abundant cultural differences apparent in these Indian marital ads, we nevertheless found the same pattern of sex differences we had found in North American and European samples. When an Indian woman's relatives advertised to find her a husband, they asked for a slightly older man regardless of her age. As Indian men aged, their relatives sought women who, relative to the men, were progressively younger and younger.

But wait. India is not a European society, but it was for a time under the rule of Britain. Although the marital ads demonstrated that British rule had not eradicated many of the central features of Indian culture—such as the caste system and the emphasis on the Hindu Zodiac—a skeptic could still argue that the preference for young women to marry older men was a result of British rule. That possibility, however, seems increasingly unlikely in the face of evidence from a range of cultures; similar age differences in mating patterns have now been reported among Brazilians, African pastoralists, and Pacific Islanders. For example, Nenita Estrera and her students sent us data on marriage ages recorded from 1913 to 1939 in a remote
Philippine fishing village called Poro. Poro marriages fit perfectly with the modern American pattern, and with the Dutch, German, and Indian data. Indeed, older men on Poro married even younger women than their counterparts in America, a detail that poses a particular problem for those who would attribute the phenomenon to American media images. It became clear that the phenomenon of older men marrying younger women is not limited to American culture or to the modern era.

As a younger fellow, incidentally, I had high hopes of not growing into a dirty old man. As it turns out, I failed miserably, but in a way that made me one more data point in this survey. My first wife, whom I married in my early twenties, was born the same year as I was—a fellow member of the generation of college students who listened to Jimi Hendrix and Frank Zappa at 33⅓ rpm. My second wife, whom I married in my late thirties, was a decade younger, educated with ZZ Top and Steely Dan playing in the background. My third (and I hope my last) wife, whom I married in my mid-fifties, is still another decade younger, from the generation that gave the world Vanilla Ice and the Smashing Pumpkins.

I began this book describing how a random work-avoiding visit to the school bookstore led to a revolutionary change in my worldview—when I stumbled across Jane Lancaster's evolutionary account of primate social behavior and the emergence of human culture. Many years later, after I had published my findings on the universal attraction between older men and younger women, I was rummaging through the anthropology section of a used bookstore. I chanced to pick up a dusty old ethnography, titled
The Tiwi of North Australia
, by the anthropologists C. W. M. Hart and Arnold R. Pillig. I am fairly certain that the other bookstore customers heard me gasp as I began reading about this group
of aboriginal Australians. The Tiwi's customs seemed to call for another worldview disruption, for they seemed to challenge my view that the attraction to younger women was universal, and to support the view that the mind was a completely blank slate.

As the authors of the Tiwi account noted:

A society in which men were more attracted to postmenopausal women than to young fertile women was shocking for more than one reason. It posed a problem not only from the perspective of evolutionary psychology, but also from the perspective of Biology 101. How could the members of such a society reproduce themselves?

I began to dig more carefully into the Tiwi ethnography. A closer examination revealed that Tiwi society was distinct in a number of interesting ways. But although young Tiwi men do in fact marry older women, they are, like men in other societies, attracted to young women as sexual partners. Indeed, Tiwi men are obsessed with younger women. A big problem in Tiwi society was keeping unmarried young men away from young women, and there were stern rules designed to accomplish this end. If a young guy was caught messing around with a young woman, he could be gored with a hunting spear, or he could be expelled from the group (which at that time in northern Australia may have been tantamount to a death sentence).

Why all the concern about separating the young men and women? The answer lies in two other features of Tiwi society, and those features also resolve the more troubling biological question of how the Tiwi reproduce themselves if all the young men are married to elderly women.

First, let us ask, Where are the fertile young Tiwi maidens while all the young men are marrying elderly women? Are they waiting around till they reach forty-five or fifty years of age for an opportunity to marry a twenty-five-year-old man, who will take no bride before she fully matures? No. The young maidens are all already married. In fact, all the females in Tiwiland marry quite young—at birth, in fact! Whom do they marry? The old powerful patriarchs—who rule with a firm hand and use their extensive power to monopolize every single one of the young women. When a Tiwi girl is born, she is immediately betrothed. Her father chooses her husband, and according to anthropologists Hart and Pillig, the old man considers her “an asset . . . to be invested in his own welfare.” What makes the daughter such an asset is this: The society is polygynous, and older men mostly betroth their young daughters to other patriarchs, who are in a position to reciprocate when one of their wives has a daughter. So the older men exchange younger women with one another, and the young blokes, with no daughters to offer, are out of the game, completely excluded from obtaining young wives who could bear them daughters.

As in all societies, young Tiwi men are nevertheless attracted to young Tiwi women, and young women do sometimes fall for young men (who are probably much more physically attractive than their elderly husbands). This allows the occasional young man to steal some contact with a young woman. But the Tiwi patriarchs are ever alert for such incursions into their monopoly on fertile women, and they enforce severe punishments on any young Romeo caught running around with a fertile young Juliet. The standard punishment is this: The young man must stand in the center of the village and allow the elder cuckold to throw a spear at him. The young fellow can jump out of the way, but then the elder gets another shot, and another, until he scores a hit. Another troubling twist for the young man: If he keeps jumping completely out of the way, the other elders pick up their spears to help their fellow patriarch save face, and
then the young man confronts a shower of spears coming at him. Ideally, the young fellow allows the wronged old man to hit him in the leg, sheds some blood, and the case is closed. But sometimes he does not jump in the right direction, and the spear pierces his upper body, so the young fellow can die from the wounds. (Even a leg wound was no laughing matter in a time and place with neither antiseptics nor antibiotics.)

The harsh patriarchal sanctions explain why younger men and women do not marry, but not why young men and older widows marry. Other features of the social system help solve the puzzle. To allow themselves to control all the young brides, the older men enforce a rule requiring that all Tiwi females (but not all males) be married. So as I mentioned, a girl is betrothed to an older man as soon as she is born. But there is another side to the female marriage rule: As soon as an older man dies, his widow or widows must remarry. The powerful older men, who frequently have numerous young wives, are not interested in marrying the older women. So who is an elderly widow going to marry? At this point, a younger man steps up. What's in it for him? By marrying a widow, the young man builds alliances with her relatives, and he gets the right to determine whom her younger daughters marry if they become widowed early (remember, all the young girls are also officially married to elderly guys, so when an old fella kicks off, he may leave some fertile younger wives as well as the older ones). Once a young man marries a widow, then, he is in the game. His status goes up, and he becomes eligible to acquire younger wives.

So instead of overturning the evolutionary life history model, the Tiwi pattern suggests a dynamic interaction between an evolved psychological mechanism (men's attraction toward women in the years of peak fertility) and local social ecology (a geriatric patriarchy that monopolizes younger women for themselves, in combination with a rule that all women must be married).

The Tiwi case is just one example demonstrating that the human mind is hardly a blank slate when it comes to absorbing and constructing cultural practices. Although human societies vary in numerous ways, those variations are not infinite and are not random, and they do not typically violate general principles that apply to all animal species. Although there are a few intellectual holdouts, most social scientists today would agree that the mind is not well characterized as a completely blank slate. But despite the general agreement that John Locke's old metaphor is outdated, it has kept its appeal as a simple and memorable image. We ought to replace it with an image that is equally straightforward and understandable.

John Tooby and Leda Cosmides have suggested one interesting alternative: the mind as a jukebox. Compared with a blank slate, a jukebox is pleasingly interactive; what comes out of a jukebox is determined not solely by what is inside, nor by outside inputs alone (pressing F6 does not result in a tune unless there is a record inside corresponding to that button). The jukebox has one limitation, though: Many cultural norms are not straightforward, automatic consequences of pushing a particular set of preordained buttons. There is some flexibility, and the potential for unexpected combinations of different norms, as we saw in the case of the Tiwi.