The Science of Large Breasts, and Other Evolutionary Verities

I blogged nearly a year ago about a study by the evolutionary psychologist Satoshi Kanazawa which argued that beautiful women sometimes marry unattractive men because of the following supply/demand gap: there are simply more good-looking women than there are good-looking men. One reason, Kanazawa said, is that beauty is a more valuable trait for a female, and is therefore accentuated in females via natural selection. Kanazawa and Alan Miller have now co-authored a book called Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire — Two Evolutionary Psychologists Explain Why We Do What We Do, to be published in September.

First of all, whoo!, long subtitle.

Second of all, there is a sizable excerpt of the book in the current Psychology Today, which includes ten bite-size “politically incorrect truths about human nature” that make the book sound like a blend of Why Do Men Have Nipples, Survival of the Sickest, and maybe … Mad magazine?

Here are the ten topics:

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

2. Humans are naturally polygamous;

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

4. Most suicide bombers are Muslim;

5. Having sons reduces the likelihood of divorce;

6. Beautiful people have more daughters;

7. What Bill Gates and Paul McCartney have in common with criminals;

8. The midlife crisis is a myth-sort of;

9. It’s natural for politicians to risk everything for an affair (but only if they’re male); and

10. Men sexually harass women because they are not sexist

In the excerpt, some of the explanations are far more compelling than others. I will chalk this up to the limitations of excerpting. Here, for instance, is Kanazawa and Miller’s explanation of why men like large-breasted women:

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.

Large breasts as a helpful indicator of age? Really?

I would think that, even during the Stone Age, if a man had to resort to judging a woman’s age by the relative sag of her breasts instead of a number of other signifiers, he probably wasn’t the kind of fellow who was going to successfully reproduce anyway.


Alsadius

How about going with the really obvious answer - evolutionarily successful men prefer women. Large breasts are the most obvious sign of a woman, since they're one of two obvious external differences between the genders(the other being male levels of hair, especially in eras with low levels of shaving). There are psychological tie-ins too, since men prefer women that look like women. It also explains why there's an upper limit on most guy's desired breast size, which the author's explanation does not. It's really not that hard to figure out.

discordian

I've always judged a woman's age by her hands.
Tightness of skin, veins, wrinkles on hands, spots... a lot harder to modify through surgery.

prosa

I'll avoid matters of a mammary nature to point out that the "most suicide bombers are Muslim" claim is incorrect. Japanese kamikaze pilots were the original suicide bombers and probably still hold the record for the most deaths caused by their activity (shouldn't Satoshi Kanazawa know that?) Today, the most active and by far the deadliest suicide bombers are the mostly Hindu Tamil separatists in Sri Lanka. I have read, though I do not remember the source, that over the past couple decades Muslims have accounted for well under half of all suicide bombers.

econ2econ

It's not that breast-size is tied to lactating ability, but rather it is indicitave of femininity, as #1 pointed out. Men are usually drawn to women who exhibit the strongest properties of femininity, which equals larger breasts, larger hips, softer features. Women are drawn to men who exhimit the strongest properties of masculinity, such as broad shoulders, square jaws, more body hair (brows and arms, with chest hair not so much anymore), tall frames, etc. These are the best outward indications of strong female/male hormones, which are desirable in reproductive terms.

giromide

What about big fake breasts versus big real breasts? I find the former odd and almost repulsive but find the later beautiful and aesthetic.

Ike Pigott

Giromide: - Why do you have to "find" them? They tend to reside in fairly conspicuous and consistent places. ;)

egretman

20% of men like women with big breasts. 20% of men like women with small breasts. The rest like something in between.

egretman

...god, that was the oldest joke in America.

frankenduf

I always thought the breast thing was freudian- but now, it seems the pseudo-evolutionary stories prevail- and what's with #1?- do we pretend to know what a "bombshell" is?- if so, then it's a tautology (men like hot women)- if not, why the descriptor?- say gentleman prefer blondes

kah

It is fun to make things up. My personal taste is for the "species differentiation" type of speculation, for what it's worth, which is zilch, but who cares. Here is how that line of hand-waving goes.

Why is trait X attractive? Because it is disproportionately extreme in humans. Why is this good? Two reasons. One, when you see it you can tell you are not accidentally mating with a different species. Two, if you reinforce it by mating with it you are helping to drive the human species farther into a successful ecological niche.

What does this have to do with the example at hand? Large breasts in non-lactating females are extreme in humans, not in other apes.

egretman

it's a tautology (men like hot women)

Yes, and how to explain the flat-breasted super model? The whole thin-is-in phenomenon? And the fact that upper socio-economic women actually get breast reductions so as not to appear "cheap".

Some of these 10 topics makes one wonder if neocons are abandoning the political arena (where they have done so well!?) and are now entering the pop-psychology field. Just another continuance of their philosophy that "any new idea must be a good idea."

econ2econ

Because straight men don't run the fashion and modeling industries. Body size has long been a pysical expression of wealth. It used to be that the fatter you were, the wealthier you were (as the poor couldn't afford to eat well). Now being thin is an expression of wealth, as it shows you can afford pricier "health" food, personal trainers, etc. It's also an indication of youth, as young women who haven't had children usually have better bodies. So maybe there's some sort of virginity desire at play there, too.

It's the same thing with tanning. It used to be that if you were pale, you were considered rich, as you could afford to be inside all day, and the workers in the field were the ones who got tan. When vacationing to exotic locales became popular among the wealthy, it became popular to be tan. There appears to be a reversal of that now as skin cancer threats have prompted most educated people to refrain from tanning, and tanning is now seen as a "trashy" kind of look. There are some exceptions among the Hollywood crowd, but most of them are using the spray-on tanners now.

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vikramadith

Some of the things mentioned in that site are ridiculous to say the least. But the one about Muslims turning to suicide bombers so that they could get sex was the funniest one! HAHA. Seriously, the ones who recently botched up an attack in UK were Doctors for crying out loud! In India, that would have given them the pick of the chicks for marriage. Why grow a beard and drive a burning jeep after that?

egretman

vikramadith, you have bumbled your way into an essential truth far beyond your wit and wisdom that any of us could have reasonably expected you to possess.

As a result, could you help us with this other bit of wisdom, "are simply more good-looking women than there are good-looking men." In particular, could you help me decide if Kanazawa is truely capably of deciding what a good-looking man is for all women?

kitman

I read once somewhere (probably shouldn't believe me already) that men are attracted to a woman's breasts because it reminds them of their buttocks and hence her reproductive organs.

EorrFU

I would think that large breasts are a sign of fertility. Since breast size tends to increase when breast feeding it is an external sign that the woman has probably had a child and not necessarily a way to determine age.

andrevalente

Even the premise that men like women with large breasts is debatable, or at least culture dependent. In many cultures (e.g., South America) men like women with small breasts.

egretman

Why do women accentuate their breasts?

You might as well ask why a peacock has all those feathers? Why pimps drive flashy cars? Or why insects put out pheromones?

Oh...wait...we already know the answer to all these questions. The only real question left in evolution is this,

Why was Laura ever attracted to George?

DigitalAutumn

the one about Muslims turning to suicide bombers so that they could get sex was the funniest one! HAHA. Seriously, the ones who recently botched up an attack in UK were Doctors for crying out loud! In India, that would have given them the pick of the chicks for marriage. Why grow a beard and drive a burning jeep after that?

Your failure here is that you've failed to show any correlation between marriage and having sex.

DigitalAutumn

I would think that large breasts are a sign of fertility. Since breast size tends to increase when breast feeding it is an external sign that the woman has probably had a child and not necessarily a way to determine age.

While we're being amateur biologists (isn't this what we're supposed to read the books for?) I'll point out that breast size increase during nursing is not universal, and it is not permanent. So, it would be a brief and redundant (since the child would be right there) indicator.

Also, breast size variety before pregnancy is so wide, the change in an individual's breast size during pregnancy wouldn't seem to be enough to allow a male to determine anything from it. In other words many women have larger breasts pre-pregnancy than many other women post-pregnancy. So it would be a poor indicator.