Sunday, November 25, 2007

Are tall women like Porsches?   posted by agnostic @ 11/25/2007 11:21:00 AM

We have already seen that female adult film stars are just average in height, while sexy celebrities are a half-sigma above-average. However, consider the heights of the 2007 Miss World contestants, whose median is 68.9 in (N = 106), a clearly significant difference from the US mean of 64.1 in. (where an SD = 3 in.), let alone the mean height of the second and third-world countries that most of the contestants come from. And though I can't find the original cite, many websites quote the Association of Modeling Agents as saying that female models should be at least 5'8. So, if tall women are not more attractive physically, as the first two data-sets suggest, but are more glamorous or prestigious, as the latter two suggest, there is a simple account of all of the data.

First, it's worth reviewing a few key facts about tall women and successful men, which come from Jensen & Sinha's (1993) excellent review of the physical correlates of intelligence. There is a positive correlation between height and IQ of roughly 0.2 -- however, all of this is due to between-family differences, as there is no within-family differences.

In other words, while members of tall families tend to be smart, within a given family, there is no relationship between height and IQ. Therefore, we can rule out some genetic causes such as pleiotropy, where a gene has effects on more than one trait; and genetic linkage, where genes for height may lie close to genes for IQ and be pulled along with them like teammates in a game of Red Rover. Common environmental causes like nutrition do not likely account for the pattern since most of the data comes from first-world populations not subject to much environmental stress, and also because the height-IQ correlation holds even among those with gifted IQs, who do no inhabit slums or want for basic nutrients.

Interestingly, the height-IQ correlation is entirely due to differences in leg length, since the correlation vanishes when sitting height is used instead of standing height. The simplest explanation that Jensen & Sinha propose is that there is cross-assortative mating between female leg length and male IQ. They summarize several studies which show that tall women, no matter what economic class they are born into, tend to climb the economic ladder more easily and marry higher-status husbands. That pools tall and smart genes into the same family, but any given kid of theirs doesn't get to pick and choose which parent he gets his height or IQ genes from, which explains why height and IQ are uncorrelated within families. Moreover, this is not a pattern only among the rich and bright: at every level of IQ, the pattern holds.

Jensen & Sinha suggest that men find tall women physically more attractive, and they mention the heights of Miss Universe contestants as support. But as we've seen, beauty pageant contestants and runway models are an entirely different group from adult film stars and sexy celebrities, who more accurately reflect what males find physically attractive. Therefore, to the extent that tall women are preferred as mates, it is probably so that the man can show her off as a hard-to-acquire status symbol, like a Porsche. This is an honest signal of high status since you don't have to conduct studies to know that a guy with a tall wife is far more likely to be a somebody than a nobody. That's especially true when the woman is not just tall, but taller than her mate, as shown in this gallery of famous shorter man / taller woman couples. We leave aside what makes a man high-status -- it could include wealth, power independent of wealth (as with Dennis Kucinich), and so on.

Broadcasting his status in this way might allow him to attract the attention of a large number of attractive onlooking females, who he may then seek on-the-sly copulations with. It may also allow him to be taken more seriously by his male colleagues and inferiors, and so to rise further in status: "Hey, that guy has a 6' tall wife -- he must be a real go-getter." Both of these effects serve to increase his reproductive fitness. And importantly, parading around your tall wife is a far less vulgar signal of status than, for example, driving up in an obscenely expensive car or sporting tons of jewelry. Consequently, the man does not suffer a loss of reputation as he would with those other signals, and because it is less conspicuous, he is less likely to draw the ire of those around him. He will provoke class envy in them, for sure, but he has to be careful not to enrage or offend them either, since social politics are central to his status.

Finally, because height is highly heritable, he may seek a taller wife more as a long-term wife than a short-term fling since he is concerned about the upward mobility of the children who he invests in. Mating with a tall woman will give his kids a leg up in the status competition. In the case of on-the-sly mating, he will not invest much in them later on, so he could be less worried about their social mobility -- just have a lot of them and hope some do well.


Jensen, A. & S. Sinha (1993). Physical correlates of human intelligence. In P. Vernon (Ed.), Biological approaches to the study of human intelligence, pp. 139-242.

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