‘I want a girl just like the girl … that married dear old Dad.’

‘I want a girl just like the girl … that married dear old Dad.’ – mate selection

Jared Diamond

Wherever lusty young bachelors gather — be it in a UCLA locker room or a New Guinea jungle camp — the discussion often gravitates to women and sex. One evening while I was camping with some New Guinea men of the Fore tribe, the conversation took its usual turn, and they explained to me their taste in women: ”The most beautiful women are Fore women. They have gorgeous black skin, thick, dark frizzy hair, full lips, broad noses, small eyes, a nice smell, and perfectly shaped breasts and nipples. Women of other New Guinea tribes are less attractive, and white women are unspeakably hideous. Just compare them with our women to see why: white skin like a sick albino’s, straight hair like strings, sometimes even hair colored yellow like dead grass or red like a poisonous snail, thin lips and narrow noses like axe blades, big eyes like a cow’s, a repulsive smell when they sweat, and breasts and nipples of the wrong shape. When you gt ready to buy a wife, find a Fore if you want someone beautiful.”

One of the reasons I didn’t follow that advice was that I happen to find those ”unspeakably hideous” women attractive. But then, I was conditioned by my own society’s ideals, just as my Fore friends were by theirs. Darwin said that every people he knew about — Chinese, Hottentots, black Africans, Fijians, etc. — measure beauty by their own appearance. Are there really no universal rules of human beauty and sex appeal? If not, do we inherit our particular taste in spouses through our genes, or do we learn it by looking at other members of our society?

Those questions become more intriguing when one compares what turns different people on within the same culture. Think of the men or women you find sexually attractive. If you’re a man, do you prefer women who are blonde or brunette, for instance, tall or short, flat-chested or buxom, and with big or small eyes? Probably you don’t go for just anyone, but only certain types. Everyone can name friends who got divorced and then chose a second spouse who was the spitting image of the first one. A colleague of mine went through a long series of plain, slim, brown-haired, round- faced girl friends until he finally found one he got along with and married her.

The particular ideal that each of us pursues is an example of what is called a search image. (A search image is a mental picture against which we compare objects and people around us in order to be able to recognize something quickly, like a Perrier bottle among all the other bottled waters on the supermarket shelf, or one’s child from other kids at a playground.) How do we develop our private search image for a mate? Psychologists have tackled this question by examining many married couples, measuring everything conceivable about their physical appearance, and then try- ing to make sense out of who married whom. The answer isn’t one that would leap out at you immediately if you just looked at a few married couples. That’s because we don’t select our own mates for their bodies as carefully as we select the mates of our show dogs, race horses, and beef cattle. But we select nevertheless.

If you measure enough things about enough couples, the answer that finally emerges is unexpectedly simple: on the average, spouses resemble each other slightly but significantly in almost every physical feature. That goes not only for the traits you’d think of first, like skin and eye and hair color, but also for an astonishing variety of other traits, such as thickness of lips, breadth of nose, length of ear lobe and middle finger, circumference of wrist, distance between eyes, and lung volume. Experimenters have made this finding for people as diverse as Poles in Poland, Americans in Michigan, and Africans in Chad. If you don’t believe it, try noticing eye colors (or measuring ear lobes) the next time you’re at a cocktail party with many couples, and then use your pocket calculator to give you the correlation coefficient. (A correlation coefficient of plus one would mean consistently identical, minus one would mean consistently opposite, and zero would mean no relationship between the two values. Coefficients between spouses are typically plus 0.9 for religion and politics, plus 0.4 for personality traits, and plus 0.2 for physical traits. Between non- marital sex partners I’d expect lower coefficients for religion and politics, higher ones for physical traits, but tests of this prediction must await a future Ph.D. thesis.)

So, we tend to marry someone who looks like us. But hold on. The man who looks most similar to a woman is her fa- ther or brother, and the best matched mate for a man would be his mother or sister. Am I saying that people tend to marry their parent or sibling of the opposite sex? Certainly not: most of us obey the incest taboo. What I’m saying is that people tend to marry a person who looks like the parent or sibling of the opposite sex. Our behavior is summed up by a popular song of the 1920s:

I want a girl

Just like the girl

That married dear old Dad . . .

So the reason we tend to resemble our mates is that many of us are looking for someone who reminds us of our parent or sibling, who in turn resembles us. We begin to develop our search image of a future sex partner as children, and that image is heavily influenced by those of the opposite sex whom we see most often. That’s usually Mommy (or Daddy) and Sister (or Brother), plus close childhood friends. But if your wife isn’t a dead ringer for Mommy, you needn’t see a shrink about your pathological search image. After all, studies consistently show that factors like religion and personality affect our choice of spouse much more strongly than physical appearance. All I’m making is the obvious point that physical traits have some influence.

Also, since lots of independent physical traits enter into our search image, most of us end up with a mild average resemblance to our spouses in many traits, rather than with a very close resemblance in a few traits. This idea is known as the ”buxom redhead theory.” If a man’s mother and sister were both buxom redheads, he might grow up to consider buxom redheads very exciting. But redheads are relatively rare, and buxom redheads still rarer. Furthermore, the man’s preference even in a casual sex partner is likely to depend on other physical traits as well, and his preference in a wife will certainly depend on her views about children, politics, and money. Hence, in a group of sons of buxom redheads, a few lucky ones will find a girl like Mommy in those two re- spects, some will have to settle for buxom non-redheads, others for non-buxom redheads, and most for run-of-the-mill non-buxom non-redheads.

It’s not just the case, then, that Fore men prefer Fore women over California women, and vice versa: our search images are much more specific. However, these insights still leave questions unanswered. Did I inherit or did I learn my search image for someone like Mommy? If I were offered the choice of sex with my sister or a strange woman, I would certainly reject the offer of my sis- ter and probably my first cousin, but would I prefer my second cousin over a strange woman (because the cousin probably resembles me more)? There are some crucial experiments that would settle these questions — e.g., keeping a man in a large cage with his female first, second, third, fourth, and fifth cousins, counting how many times he had sex with each, and repeating the experiment with many men (or women) and their cousins. Such experiments are hard to do with humans, but they’ve been done for several animal species, with instructive results. I’ll give just two examples: the cousin-loving quail and the perfumed mice and rats.

Consider first the case of Japanese quails, which are either brown or white. The preferences of male quails have been tested by putting a male in a cage with two females and observing with which female the male spent more time or copulated (see chart, opposite page). It turns out that males preferred whichever color of female they grew up with. When a brown-loving male was given a choice between brown females that he had never seen before (although some were his relatives from whom e had been separated before hatching), he preferred his first cousin to his third cousin or an unrelated female, but he also preferred his first cousin to his sister. Evidently, as male quails grow up they learn the appearance of the sisters (or mother) with whom they’re reared, then seek a mate who’s very similar but not too similar. Like other things in life, inbreeding seems to be good in moderation. For instance, among unrelated brown females, a male prefers an unfamiliar one to one he grew up with (a ”pseudo sister,” who pushes the male’s not-too- much-incest button).

Mice and rats also learn in childhood what to look for in a mate, but they choose by smell more than by appearance. When infant female mice were reared by parents sprayed repeatedly with Parma violet perfume, on reaching adulthood they sought out Parma- Violet-scented males in pref- erence to unscented males. (”I want a boy, just like the boy that smells like dear old Dad.”) In another experiment, infant male rats were reared by mothers whose nipples and vagina were sprayed with lemon- scented citral, and each male on reaching adulthood was put in a cage with a lemon-scented or an unscented female rat. The encounters were video- taped and played back to note the times of key events. It turned out that males with scented mothers mounted and ejaculated more quickly when placed with scented females than unscented ones, while males with unscented mothers preferred unscented females (see chart, above). Obviously, the males had learned to be sexually excited by Mommy’s smell; they didn’t inherit the knowledge.

What do these experiments show? The message is clear: animals of those species learn to recognize their parents and siblings as they grow up, then are programmed to seek out an individual fairly similar to the parent or sibling of the opposite sex — but not Mommy or Little Sister herself. They may inherit some search image of what constitutes a rat, but they evidently learn their search image of who in particular is a beautiful, eligible rat.

We can immediately appreciate what experiments are needed to get unequivocal proof of this theory for humans. For example, we could take an average happy American family, spray Daddy every day with Parma Violet, spray Mommy’s nipples daily with lemon oil while she’s nursing, and then wait twenty years to see whom the sons and daughters marry. Alas, we’d be frustrated by the many obstacles to establishing Scientific Truth for humans. But some observations and accidental experi- ments still let us tiptoe toward the truth.

Take the incest taboo. Scientists debate whether it’s instinctive in humans or learned. However, this article is concerned with a separate question: Given that we somehow acquire an incest taboo, do we learn to whom to apply it, or do we inherit that information in our genes? Normally, we grow up with our closest relatives (parents and siblings), so our subsequent avoidance of them as sex partners could equally well be genetic or learned. But adoptive brothers and sisters also tend to avoid incest. And children raised together on Israeli kibbutzim almost never marry each other. A study of 2,769 people brought up on kibbutzim revealed not only no marriages between individuals cared for in the same peer group since birth, but no adolescent or adult heterosexual activity either. However, there were 13 marriages involving peer-group members separated before the age of six. Thus, we learn that the incest taboo applies to a person with whom we were brought up in ear- ly childhood, regardless of whether that person was a true sibling.

We also appear to learn the part of the search image that tells us whom to seek, not just the part that tells us whom to avoid. For instance, a friend who is 100 per cent Chinese but grew up in a white community found herself attracted only to white men, despite having moved as an adult to

an area with many Chinese men. Think to yourself: What sort of men or women do you find physically attractive, and where did you develop that taste? I’d guess that most of you, like me, can trace your preference to what your parents or siblings or childhood friends look like.

So don’t be discouraged by those old generalizations about sex appeal — gentlemen prefer blondes, men seldom make passes at girls who wear glasses, etc. Each such ”rule” applies only to some of us, and there are plenty of men out there whose mommies were myopic brunettes. Fortunately for my wife and me — both of us brunets requiring glasses, born of brunet, glasses-wearing parents — beauty is in the eye of the beholder.

COPYRIGHT 1986 Discover

COPYRIGHT 2004 Gale Group