Monday, July 09, 2007

Why Beautiful People Have More Daughters. Part 2.

Did you read the post below first? If so, you are ready for this one, in which I'm going to comment on the first three of the ten "politically incorrect" truths. The rest will be discussed in Parts 3. and 4. of this series.

First a caveat: Note that I am not an evolutionary psychologist, although I'm pretty good at statistics. This combination means that I can spot certain problems fairly easily but might miss other problems altogether.

It may also mean that I don't get a valid point. This is sad, but given the current incentive structure in academia I might wait a very long time for a real evolutionary psychologist (not Evolutionary Psychologist, see Part 1. below) to turn up and spend time and effort in the necessary refutations. Sadly, there is nothing for them in that kind of work. Promotions or tenure are not based on it, but on their own scientific work. That, in turn, is hardly ever discussed in the popular media because it's not controversial enough. -- In short, I'd love to stop talking about this crap. Could someone else take it on, please?

Then to the ten points. They all share two things: They pick something that in general is not the most common feature of modern life and they elevate it to a biological truth, and they ignore the most obvious (proximal) explanations in favor of a rather exaggerated evolutionary scheme. It is in the exaggerations that Evolutionary Psychologists most irritate me.

Here is the first of the politically incorrect points in the article:

1. Men like blond bombshells (and women want to look like them)

Long before TV—in 15th- and 16th- century Italy, and possibly two millennia ago—women were dying their hair blond. A recent study shows that in Iran, where exposure to Western media and culture is limited, women are actually more concerned with their body image, and want to lose more weight, than their American counterparts. It is difficult to ascribe the preferences and desires of women in 15th-century Italy and 21st-century Iran to socialization by media.

Women's desire to look like Barbie—young with small waist, large breasts, long blond hair, and blue eyes—is a direct, realistic, and sensible response to the desire of men to mate with women who look like her. There is evolutionary logic behind each of these features.

Men prefer young women in part because they tend to be healthier than older women. One accurate indicator of health is physical attractiveness; another is hair. Healthy women have lustrous, shiny hair, whereas the hair of sickly people loses its luster. Because hair grows slowly, shoulder-length hair reveals several years of a woman's health status.

Men also have a universal preference for women with a low waist-to-hip ratio. They are healthier and more fertile than other women; they have an easier time conceiving a child and do so at earlier ages because they have larger amounts of essential reproductive hormones. Thus men are unconsciously seeking healthier and more fertile women when they seek women with small waists.

Until very recently, it was a mystery to evolutionary psychology why men prefer women with large breasts, since the size of a woman's breasts has no relationship to her ability to lactate. But Harvard anthropologist Frank Marlowe contends that larger, and hence heavier, breasts sag more conspicuously with age than do smaller breasts. Thus they make it easier for men to judge a woman's age (and her reproductive value) by sight—suggesting why men find women with large breasts more attractive.

Alternatively, men may prefer women with large breasts for the same reason they prefer women with small waists. A new study of Polish women shows that women with large breasts and tight waists have the greatest fecundity, indicated by their levels of two reproductive hormones (estradiol and progesterone).

Blond hair is unique in that it changes dramatically with age. Typically, young girls with light blond hair become women with brown hair. Thus, men who prefer to mate with blond women are unconsciously attempting to mate with younger (and hence, on average, healthier and more fecund) women. It is no coincidence that blond hair evolved in Scandinavia and northern Europe, probably as an alternative means for women to advertise their youth, as their bodies were concealed under heavy clothing.

Women with blue eyes should not be any different from those with green or brown eyes. Yet preference for blue eyes seems both universal and undeniable—in males as well as females. One explanation is that the human pupil dilates when an individual is exposed to something that she likes. For instance, the pupils of women and infants (but not men) spontaneously dilate when they see babies. Pupil dilation is an honest indicator of interest and attraction. And the size of the pupil is easiest to determine in blue eyes. Blue-eyed people are considered attractive as potential mates because it is easiest to determine whether they are interested in us or not.

The irony is that none of the above is true any longer. Through face-lifts, wigs, liposuction, surgical breast augmentation, hair dye, and color contact lenses, any woman, regardless of age, can have many of the key features that define ideal female beauty. And men fall for them. Men can cognitively understand that many blond women with firm, large breasts are not actually 15 years old, but they still find them attractive because their evolved psychological mechanisms are fooled by modern inventions that did not exist in the ancestral environment.

There is so much in this one point to discuss, so much. But I'm going to limit myself to just a few points.

First, the preference for large breasts is not universal. People at different time periods and in different countries have focussed on different parts of the female body, from thighs (in Elizabethan England), to hips (in much of the Caribbean) to the nape of neck (in Japan at one time). If breasts are more in fashion now it may well have to do with the American domination through movies and popular culture in general.

Second, the 0.7 waist-to-hips ratio was initially established in a study done in the U.S.. Its supposed international applicability was based on the fact that some of the students used in the study had roots in various other countries. It's possible that later studies have been done to prove this one, but Anne Innis Dagg (in "Love of Shopping" Is Not A Gene) reports on several studies on nomadic and semi-nomadic tribes in Tanzania and Peru which found that the men in those tribes preferred women shaped big and tubular, not like an hour-glass, because the former shape was associated with a fatter woman and hence a better worker. Once some of these men got into contact with Western lifestyles their preferences changed. -- This suggests that it is very difficult to disentangle "evolutionary" explanations from the cultural hegemony the Western nations currently have.

Third, the blonde thingy. The authors write: "Blond hair is unique in that it changes dramatically with age. Typically, young girls with light blond hair become women with brown hair. Thus, men who prefer to mate with blond women are unconsciously attempting to mate with younger (and hence, on average, healthier and more fecund) women. It is no coincidence that blond hair evolved in Scandinavia and northern Europe, probably as an alternative means for women to advertise their youth, as their bodies were concealed under heavy clothing."

Ok. If this explanation works, how come are the Inuit women not mostly blonde, too? Their clothing covered sagging breasts even better than the Scandinavian clothing. Then that stuff about blond hair changing to brown hair and so on, to show age. Actually, a lot of Scandinavian blond hair doesn't change at all with age, until the final whitening. And black hair shows aging pretty convincingly, too, in the sense of gray hair. But the oddest part of this explanation is the idea that all this selection took place in women but caused by men.

Sigh. This is really boring. When I was growing up in Finland what was really exotic was dark brown or black hair. Now that got you dates! I suspect that blond hair is valued in other countries, because it is relatively rare. Oh, and on the blue eyes. They were boring in Finland, because they are the most common types of eyes there.

Let's move to the second politically incorrect fact in the article:

2. Humans are naturally polygamous

The history of western civilization aside, humans are naturally polygamous. Polyandry (a marriage of one woman to many men) is very rare, but polygyny (the marriage of one man to many women) is widely practiced in human societies, even though Judeo-Christian traditions hold that monogamy is the only natural form of marriage. We know that humans have been polygynous throughout most of history because men are taller than women.

Among primate and nonprimate species, the degree of polygyny highly correlates with the degree to which males of a species are larger than females. The more polygynous the species, the greater the size disparity between the sexes. Typically, human males are 10 percent taller and 20 percent heavier than females. This suggests that, throughout history, humans have been mildly polygynous.

Relative to monogamy, polygyny creates greater fitness variance (the distance between the "winners" and the "losers" in the reproductive game) among males than among females because it allows a few males to monopolize all the females in the group. The greater fitness variance among males creates greater pressure for men to compete with each other for mates. Only big and tall males can win mating opportunities. Among pair-bonding species like humans, in which males and females stay together to raise their children, females also prefer to mate with big and tall males because they can provide better physical protection against predators and other males.

In societies where rich men are much richer than poor men, women (and their children) are better off sharing the few wealthy men; one-half, one-quarter, or even one-tenth of a wealthy man is still better than an entire poor man. As George Bernard Shaw puts it, "The maternal instinct leads a woman to prefer a tenth share in a first-rate man to the exclusive possession of a third-rate one." Despite the fact that humans are naturally polygynous, most industrial societies are monogamous because men tend to be more or less equal in their resources compared with their ancestors in medieval times. (Inequality tends to increase as society advances in complexity from hunter-gatherer to advanced agrarian societies. Industrialization tends to decrease the level of inequality.)

How can you say "the history is western civilization aside, humans are naturally polygamous?" Who created western civilization? Vulcans? I don't have much to say about this point, except to note that despite the promising beginning (HUMANS are naturally polygamous) the rest of the text is all about men being naturally polygamous.

The authors also define sexual relations as institutional or legal relations, which leaves out all adultery (and begs the question what the prehistoric form of all this might have been). In the chimpanzee world the females turn out to be quite "adulterous", getting impregnated by strange males behind the back of the dominant guy of their group or by any male in the group. As Evolutionary Psychologists are usually keen to apply chimp research to humans (and did so just a little earlier) it is odd that it's not happening here. Probably because the thesis being pursued here would not benefit from it, such as this argument: "Only big and tall males can win mating opportunities." Note that this assumes all mating opportunities are decided between males in fights. The females do nothing at all. They just stand there, like barrels of beer. They never take lovers.

The next point is still on polygyny:

3. Most women benefit from polygyny, while most men benefit from monogamy

When there is resource inequality among men—the case in every human society—most women benefit from polygyny: women can share a wealthy man. Under monogamy, they are stuck with marrying a poorer man.

The only exceptions are extremely desirable women. Under monogamy, they can monopolize the wealthiest men; under polygyny, they must share the men with other, less desirable women. However, the situation is exactly opposite for men. Monogamy guarantees that every man can find a wife. True, less desirable men can marry only less desirable women, but that's much better than not marrying anyone at all.

Men in monogamous societies imagine they would be better off under polygyny. What they don't realize is that, for most men who are not extremely desirable, polygyny means no wife at all, or, if they are lucky, a wife who is much less desirable than one they could get under monogamy.

This theory assumes that what matters for women in marriage is only material wealth and that the only way women can get access to such wealth is through marriage.

If one man is ten times wealthier than other men, then being one of that man's nine wives would make a woman better off, financially speaking, than marrying one of the other men as the sole wife. The problem with this argument is that there is nothing to guarantee that the man will allocate the proportionate share of wealth to each of his nine wives (men tend to have all the power in polygynous marriages), and that it ignores the competition for resources by those other wives. It also ignores the competition for fathering resources between the children of different wives and the bad effects this might have on the children. (One recent study on African polygynous families found that the children did worse healthwise than the father's resources indicated.)

I've actually been rather nice in that paragraph, because another interpretation of the argument seems to be that a slice of a husband is every bit as good as a whole husband. But if that is really true, then the surplus men in a polygynous society could simply get together and have one wife between them.

The major point here is that to understand who benefits from polygyny requires much more careful definitions about the parameters of the model. What is marriage for, in short.

This post continues (and continues) later.