Ten Politically Incorrect So-Called Truths About Human Nature: 1 – 5

When last we met Satoshi Kanazawa he was telling us that evolutionary psychology “proved” that black women were uglier than white women. Black women, he said, were bred to have more testosterone than white women, and therefore black women looked more like men, and were thus uglier. Read the linked article to discover why this hypothesis is nuts.

And then return here, because he’s back and better than ever in his Ten Politically Incorrect Truths About Human Nature from Psychology Today.

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

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.

Note first the logical truth that “mystery to evolutionary psychology” does not imply “mystery.” Many scientists have a difficult time accepting facts (true, observed verities) that do not fit neatly inside a formal theory. Beautiful hypotheses are preferred to ugly realities.

Then you have to admire the fertile imagination of evolutionary psychologists like Kanazawa. Out go banal explanations like larger breasts are easier to see, or that breast size preference is a changeable cultural artifact, and in comes a theory tangled and tortured to point to evolutionary causes.

Ignore that faces tell age better than any other marker. Marlowe asks us to believe that an early human man while considering early human women for mates—even though these ladies died early, probably in their twenties or thirties, long before age caused certain appendages to head south permanently—was able to say to himself, “Margaret Oog’s breasts are plumper than Sally Aargh’s, therefore I know that my descendants will be better able to judge the age of potential mates if I marry Margaret and pass on her mammary genes. I will disregard that Miss Oog’s shape excites my imagination now.”

Just think: any behavior that is evolutionarily encoded, and I do not doubt for a moment that such behaviors exist, must have started out as missing, as not a behavior. How did preference for larger breasts arise in the first place? And if it is so productive, why aren’t all women equipped with whoppers by now?

2. Humans are naturally polygamous

The history of western civilization aside, humans are naturally polygamous…We know that humans have been polygynous throughout most of history because men are taller than women.

It works like this: a wide-spread, deeply ingrained cultural practice, one which has existed through many eras in many place, is first declared “unnatural”, a word which means that the practice is aberrational. You next find an exception—and human cultural experience is ripe with these, so your search will often be rewarded—and then declare the exception the “norm.”

Lastly, you uncover a statistical correlation which proves the rarely practiced exception is actually the behavior that would reign if only…what? Well, apparently if only everybody would except the reasonings of evolutionary psychologists.

The correlation here is that “the degree of polygyny highly correlates with the degree to which males of a species are larger than females” and that “human males are 10 percent taller” than human females. Understand: non-humans males being taller than females in a certain species does not mean that this species automatically practices polygyny, but only that in those species where the males are taller than females more of those species than not practice polygyny. (I’m accepting this observation as true, though I doubt it: is it all species? Insects, fish too?) Not to be tedious, but correlation does not imply causation.

I’m going to repeat this so that it sinks in: whatever behavior we see of humans is the behavior we see of humans. Whatever we do is therefore natural. We do not “deviate” from what is evolutionarily optimal, we do what we do. A true evolutionary explanation must account for all ranges of a human behavior, or it must prove why it can only explain a small fraction of that range. Kanazawa’s hypothesis fails miserably here.

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

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.

We now learn that, in direct opposition to point #2, men actually benefit more from monogamy (and his reason is true). Would Kanazawa say that men derive enough benefit from monogamy that monogamy is a cultural trait that is selected by evolutionary pressures? What’s that? He has to take a phone call? Then let’s move on.

4. Most suicide bombers are Muslim

This is true, or has been true for the past fifty or so years. The fifty years before that were dominated by Japanese suicide bombers, right Satoshi? But these observations do not imply, and it is not true, that most Muslims are suicide bombers, nor was it the case that in the mid-twentieth century most Japanese were lofted and blasted by the divine wind.

Anyway, Kanazawa says that the reason more Muslims than non-Muslims are willing to blow themselves to Kingdom Come is not religion but that Islam

tolerates polygyny. By allowing some men to monopolize all women and altogether excluding many men from reproductive opportunities, polygyny creates shortages of available women…polygyny makes men violent, increasing crimes such as murder and rape, even after controlling for such obvious factors as economic development, economic inequality, population density, the level of democracy, and political factors in the region.

Yet again, the evils of polgyny are made manifest. The reader may begin to wonder how we as a species were able to breed so many of ourselves with polygyny being the “natural” state, thus encouraging so many single men to blow themselves up and engage is various forms of mayhem.

This example at least highlights the weak historical grasp of evolutionary psychology, for we remember that the earlier Japanese suicide bombers did not live in a polygynous society. And then we wonder of the women who have lately been torching themselves in Palestine and Tibet, who are not men lacking sexual opportunity. We could go on, but it is too depressing.

5. Having sons reduces the likelihood of divorce

Since a man’s mate value is largely determined by his wealth, status, and power…the father has to make sure that his son will inherit his wealth, status, and power, regardless of how much or how little of these resources he has.

And why can he not ensure that this daughter not inherit his wealth, etc.? It does not matter one whit whether in fact men actually favor their sons, the question is why they do. The inheritance theory fails because women can, and have, been primary beneficiaries. Culture appears strongly influential or even (at times) determinative here.

Kanawaza’s evolutionary imagination’s starting point is that “demographers have discovered that couples who have at least one son face significantly less risk of divorce than couples who have only daughters.” Has this always been true? Is it only true in the USA? Did these demographers account for the differences in birth rate? (Kanazawa remembers this in point #6; see tomorrow.) More males are born than females without external aid, and with external aid the discrepancy is even larger. Why compare one son with families with no sons? Is there something different about women who cannot produce sons and the men who father them? In short, there is plenty of reason to doubt the observation that begins this journey.

Tomorrow: 6 – 10


  1. “even though these ladies died early, probably in their twenties or thirties,”
    I recall reading that in Roman times the average life expectancy was about 25 years. They had none of that nasty pollution, clean water, clear air, organic food and they died early.

  2. Statements without qualification … men prefer women with large breasts … are often used to mask a feeble argument.

    A weakly qualified statement would be a truism and therefore pointless. Some men prefer women with large breasts. Plus, large is subjective, ill defined and synonymous with big, great, huge, fat, bulky, hefty, outsized and enormous.

    A strong argument with numbers and all would be too boring for Psychology Today.

  3. Ray,

    The Romans weren’t much different in attitude than we are when it came to health. They, too, had their longevity fads. The upper income folk experienced life pretty much as we do though you have to wonder how they survived without cell phones and the internet. The richer ones lived longer than the poorer ones. A large modifier of average age is the rate of infant/childhood death.

    Speed, “Some men prefer women with large breasts”

    Speak for yourself but, yeah, large doesn’t always mean attractive. There must be a reason that one of the first things a man does is stare at the chest.

  4. Mathew point 1 needs many,many photographs illustrating the range between small and large.It also needs lots of video footage showing and comparing the gravitational responses of large vs small under controlled conditions (such as running along a beach)

  5. Satoshi seems to confounding cultural fads (i.e. divorce, fashion, religion, etc.) with instinctive (and hence genetic) behaviors (i.e. violence, sex, gluttony, etc.). We have instincts, but mostly we subdue them (some of us do anyway, at least partially).

    Whether or not, and to what degree, culture drives genetic evolution in Homo sapiens is an interesting question, however.

    The use of fire, for instance, is a cultural practice (dating back ~1,6 million years) that allowed humanity (and proto-humans) to survive some near extinction events — but not without loss of certain enzymes (that is, the DNA coding for creating them within human cells). We are the only species that cooks food, and as an evolutionary result, we are genetically limited in many respects to eating only cooked foods. Many (most) raw foods are indigestable to us, but not necessarily to other animals.

    It’s not always about mate selection. BTW, breast size may have more to do with childhood nutrition than genetics.

    Will the New Technology have a similar (to the harnessing of fire) evolutionary effect? Will humanity become genetically dependent on computers? We may have to wait a million years to find out, but one could speculate:

    1. In much less time, perhaps 100 years, the Computer Adept will have failed to reproduce due to their unattractive nerdism and social retardation.

    2. Humanity will have devolved to just the Computer Inept, and computers will go extinct because nobody will be left who knows how they work.

  6. Mike D.,

    Name something that must be cooked before being edible (vs. palatable). In general, cooking is a preservation process.

    If breast size is more related to nutrition then it would seem taste tests might be more reliable than optical observation.

  7. “Satoshi Kanazawa he was telling us that evolutionary psychology “proved” that black women were uglier than white women”: are you sure? I thought he was reporting the views of others.

    As for all this “life expectancy was 25” stuff: if that is life expectancy at birth, it will be dominated by deaths in infancy, so it won’t mean that most people died in their twenties.

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

    “How did preference for larger breasts arise in the first place?”

    The obvious candidate is some form of sexual selection but the detail is more uncertain.

    Other species such as chimpanzees and baboons advertise the inexact proximity of their fertile period with a swelling around their vaginas.


    It is likely that our ancestors also did this but we have lost this trait for some reason or another, or more likely a combination of reasons. I’m not completely sure whether our lineage lost the swelling before it acquired the breast fetish but it seems likely that the same neural circuitry in males may be excited in both cases.

    If we acquired bipedal locomotion first then this might partially explain the movement of the advertising to the chest area.

    In hunter-gatherer societies, breasts may have been a good indicator of general health, age, and fertility, so it may still be useful for males to respond to the signalling.

    “And if it is so productive, why aren’t all women equipped with whoppers by now?”

    Good question.

    The trait is influenced by hormone levels so variation may be inevitable if hormone levels are variable. Explaining why it would be sensitive to hormone levels may be more complicated than hormones being a decent proxy for being in a female body. I believe there are theories on why sexual advertising will usually have a degree of honesty.

    Or perhaps the trait is not under strong selection and is effectively drifting.

    2. Humans are naturally polygamous

    There are fairly few species that can be described as faithfully monogamous and humans are not in the most faithful category.

    Sexual dimorphism in size and strength are not the only clues that suggest that suggest monogamy has not been universal in our history but it is a strong one with a solid theoretical backing. If females put more calories and time into bringing up a child then there is good reason for strong competition by males and this will reward males that are larger than the species average. When the female of a species is larger it is usually because there is a economy of scale on the egg production but I believe that the same sort of selection causing males to be larger can also cause females to be larger and more aggressive in a few species where males spend more calories and time on care, and the females deal out the same sex aggression.

    Another clue that monogamy has not been universal is that humans, like chimpanzees but not gorillas, produce way more sperm than is necessary. I believe that there are also genetic reasons which suggest that males have had a greater range of fertility success than females.

    There are also theories on why humans practise “concealed ovulation” which may increase a female mate choice more than her regular partner will know.

    “Not to be tedious, but correlation does not imply causation.”

    It is not just correlation we are talking about here, we have a pattern and a mechanism. In polygamous species such as elephant seals, the smaller males really do seem to be at a reproductive disadvantage. In monogamous species with 2 parent families there is far less sexual dimorphism.

    “A true evolutionary explanation must account for all ranges of a human behavior, or it must prove why it can only explain a small fraction of that range”

    That’s your own definition.

    “We now learn that, in direct opposition to point #2, men actually benefit more from monogamy”

    He said that most men, not all men or men collectively benefit from monogamy. Which would be true, and not in contradiction with #2, if by this he meant that men of average and below average attractiveness would have better reproductive opportunities if their more attractive competition was limited to one mate.

    4. Most suicide bombers are Muslim

    I tend to disagree with Kanazawa on the importance of polygyny in suicide bombing. So many of the suicide bombers have had excellent prospects for careers and mates but an excess of males could have been helpful for Jihad and repopulation when a fraction of the males die in each generation.

    5. Having sons reduces the likelihood of divorce

    “Culture appears strongly influential or even (at times) determinative here.”

    And where does culture come from? Culture is never independent of human nature.

    Regarding status, in different times and places it may have been difficult or impossible to pass on a status or trade to a daughter. In the past, and possibly current times, I believe that women tend to settle further away from their birthplaces and their trade may often be described as “homemaker.

    It is worth being suspicious of this demographic data. I remember Judith Rich Harris once corrected a serious miscalculation used on the “birth order effect” and found that, when family size was accounted for, firstborns are no longer disproportionately successful in the ways previously claimed.

  9. DAV wrote, ” … one of the first things a man does is stare at the chest.”

    1. What is the first thing? The second?
    2. “a man” is one out of about 3.5 billion.

    You make my point about unqualified (or poorly qualified) statements.

  10. gene machine,

    I’ll just answer two.

    #2. We did not need evolutionary psychologists to tell us of non-monogamous behavior. What truth is more obvious than this? But it does not follow that because men are larger than women that polygyny is true. The two might appear together more often than not, but so what. We still have not answered, by noticing a correlation, why polygyny follows.

    #5. “Culture is never independent of human nature.” Amen. It is the teasing out that which is genetic, and determined or mostly determined, from that which is invented, free or mostly free, that is the purview of biologists. My point is that folks like Kanazawa are doing a mighty poor job of it. People like him delight in “shocking” truths, i.e. those things that go against common sense but are known only to initiates. I have the suspicion that he longs to hear, perhaps via a New York Times, words along the lines of, “Guide us, O Kanazawa!”

  11. dearieme,

    True, but we’ve also read, many times, that a couple of hundred thousand years ago, when humanity was young and just learning their genetics, that people died young, not just on average, but young period.

  12. Speed,

    good point. It’s just as dumb as saying grass is green or the sky is blue. Much better to tediously qualify them and all similar: grass is often green and sometimes the sky is blue.

  13. Ray,

    The Romans had plenty of polution. Poo is the worst form of polution there is. They may have had the best water and sweage system of its era (and better than most other cities would have 1000 years later). But, by modern standards it was pretty filthy.

  14. DAV,

    Wild foods which must be cooked to remove poisons and become digestible to humans:

    Proto-wheat, proto-corn, proto-rice, taro, manioc, camas, indeed most wild grains and roots. Cooking also improves the digestibility of most meat and kills bacteria.

    Recommended reading: Wrangham, R.W. (2009) Catching fire: how cooking made us
    human. Basic Books, New York.

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