Assortative Mating, Class, and Caste

I have an old blog post here about assortative mating and how it can mimic very strong selection. Greg and I are just finishing a manuscript on the issue, and we would be interested in any comments and criticisms you might have. It is posted here. Thanks.

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96 Responses to Assortative Mating, Class, and Caste

  1. vaniver says:

    “The difference is 4 standard deviations on the original scale.” It looks like 4 inches, which is 1.6 standard deviations on the original scale.

    “differences in genes her” -> “differences in genes here”

    “about15%” -> “about 15%”

    “both me and women” -> “both men and women”

    Figures 2 and 3 could use a clearer separation between parents and children, I think; I might drop the first row, and make it obvious that these are the children of the two classes in generations 1, 2, and 3 after the imposition of the mating rule. Alternatively, have a different way of showing descent from right class and membership in right class for mating this period (as done in two rows of Fig 1); the 0th generation in Fig 3 is particularly troublesome in this way, and it would be nice to see where the separating line between 10/11ths and 1/11th is on the bell curve in Fig 3.

    Similarly, I might point out in the “raw material” section that in the h=1 case, the child mean and parent mean is the same for every generation, which explains why most of the work is done in the first generation- by cutting out part of the population, and putting it in another group, you can dramatically alter the mean, but you haven’t created an engine for perpetual movement. It looks to me like most of the ongoing change is reducing the standard deviation of each group, rather than adjusting the means much, but I’m guessing from seeing three generations in a picture, not looking at the numerical output over many generations.

    “after two generations the difference between groups is roughly similar”: to me, it looks like the h=.5 three generations case is closer to the h=1 one generation case than the h=.5 two generations case. (The reason I point this out is to avoid any sort of expectation that the time it takes to do this is inversely linear in h, which looks wrong from the data you’ve presented here but is hard to say for sure.)

    “father’s and son’s income” seems weird to me; might it be “fathers’ and sons’ income”? Not confident in this.

    I typically see it as STEM, not Stem. (Also, it might be interesting to see what percentage of people who go to college marry someone who went to the same college as them; doesn’t make much actual difference for the caste story, except the number of castes, but is visible support.)

    Thoughts: I can see why you do computational results, rather than algebraic ones; truncated Gaussians are no fun to work with. There might be an assortative mating rule that does play nicely with mixture Gaussians, though- maybe the probability of mating depends on the distance, rather than just the class membership? (It does seem odd to lump together the 70.5 and 80 inch person, and the 69.5 and 60 inch person, and not the 69.5 and 70.5 inch person.)

    I think, though, that this might be amenable to the algrebraic approach if you treat this as a binary equal-strength additive gene model. I’ll think about that for a day or so and let you know if I find anything interesting.

    (Also, Firefox crashed on me, so I had to write this up twice. 😦 I have the maddening feeling that I missed one of the things I caught last time, but I found at least one thing I didn’t last time, so I guess it works out. )

    • harpend says:

      Thanks, made the corrections. I quit with the analytic approach because with the simplest Fisher model the phenotype is a convolution of the genic effects and the environmental effects. In order to proceed with the analysis one would have to deconvolute the phenotype distributions and it has been too many decades since I took math stat for me to face that.

      We sure would be interested if you come up with a different direction.

      • vaniver says:

        After looking at it closely, I’m not sure the direction is all that different. The discrete computational model I’ve come up with is more transparent, I think, but it’ll generate the same sort of results for the same sort of reasons. It’s easier to tell the steady state distribution for any particular setup, it’s easier to have more complicated rules (like doing assortative mating on a only partly heritable phenotype, given the rule to generate the phenotype), but you pay for that by having a discrete distribution instead of a continuous distribution. Thankfully, I think it scales well enough that a computer can easily handle models with genes in the hundreds or thousands, so the discrete approximation is going to be very close, but doing even a 3-gene model by hand is a giant pain.

        I’ve got no experience in computational biology, though, so no guarantee that it’s new, or that I didn’t do things the dumb way when a smart way’s available. I’ll code it up soon so you can play around with it; do you have a preference between Octave, Matlab, R, or something else?

      • harpend says:

        To Vaniver:

        Would love to see your writeup. My two toys of choice are Mathematica and Python/Scipy. I understand that the latter mimics matlab so that might be the best for communicating.

        Thanks……..

      • vaniver says:

        I’ve uploaded my writeup and the first bit of code; I’d recommend running exhibit_class(), which will regenerate figure 2.
        At some point in the next week I hope to look at the other assortative mating rules I discuss in the writeup. (Exogamy is pretty boring.) There are a number of other nice features I’d like to add related to class changes- like the ability to track the percentage of people whose class differs from their parents, or class variances of parents and children- but I’m not sure how to reconcile that with the flexibility in the M matrix yet. (For example, if the M matrix is diagonalish, then there aren’t really “classes,” and we’re more interested in parent-child distance as a function with larger support, and that seems mostly determined by the gene model.)
        Also, there seem to be numerical stability issues after about 50 generations, which shouldn’t be an issue once I implement the equilibrium distribution finder.

  2. Eric says:

    How fortuitous… I was introduced to (and began reading) Coming Apart yesterday. I’m new to the subject. I also followed a new Twitter user based on a completely different subject. Today, that user linked to this.

    I think you meant to use “coarse” in the last paragraph, rather than “course.”

  3. As a general, background point to the phenomenon of assortative mating – I think it worth recognizing that (wife’s) parental choice seems to have been very important in choice of marriage partner in most historical societies – and this will likely have had a significant effect on past human evolution.

    http://charltonteaching.blogspot.co.uk/2013/09/parental-choice-determines-mating.html

    This could mean that male traits are being selected by in-laws, more than by wives.

    And this makes it much easier to understand why un-sexy traits such as conscientiousness and the ‘high systemizing’/ Asperger personality might have been amplified by their association with better economic performance – in-laws want good providers for their daughters (and bad providers would have left nearly zero offspring in the Middle Ages to to near total child mortality among the poor).

    This may also be relevant for Ashkenazi intelligence.

    Henry, I have an in press/ un-revised book chapter arguing some of this, if you want to mail me for a copy.

    • harpend says:

      Hi Bruce:

      In our model everything is neutral, but as Clark has shown there was strong selection in the middle ages for the traits you cite and assortment would have made the process a lot faster. Have to think about that……

      Would love to have a look at your chapter.

    • Matt says:

      And this makes it much easier to understand why un-sexy traits such as conscientiousness and the ‘high systemizing’/ Asperger personality might have been amplified by their association with better economic performance – in-laws want good providers for their daughters

      In-laws treating women as chattels to be sold of to the most economically successful man available seems about as likely, but would have the same kind of effects anyway (relaxation on the personal charm, warmth, sociability, kindness traits (hereafter “charm”) that women would choose naturally relative to economic success traits, even if these are all mostly correlated anyway).

      bad providers would have left nearly zero offspring in the Middle Ages to to near total child mortality among the poor

      If this effect were really strong to the point where arranged marriage traditions added marginal or no selective effect, then arranged traditions could end up resembling more a relaxation of selection on good personalities than additional selection for economic success.

      Assuming independence of “charm” and economic ability, if you had a situtation where only charming men marry, only the married have children and only the economically successful have surviving children, then

      – a smaller fraction of men would have surviving children than if all economically successful men could marry (those who are both charming and economically on the ball)

      – but their kids would have a large niche to expand into (less competition), and they would tend to be both charming and economically savvy. They’re going through two filters which select for two uncorrelated, things, producing a more “elite” (if less “aspie”) end group, not two filters, which are basically the same thing and where one of them is redundant.

    • Jack Morpher says:

      hy un-sexy traits such as conscientiousness and the ‘high systemizing’/ Asperger personality

      Me! me! me!

  4. Julian says:

    Great, would love to see you guys publish some more academic papers.

  5. Greying Wanderer says:

    If the ruling class of a society encourages maladaptive behavior they can increase the gap between themselves and the rest of society. The effect on the health and prosperity of the society as a whole is negative but in a sealed environment the relative effect for the ruling class within the society is positive.

    On the other hand if a society following that path isn’t in a sealed environment and is competing with a more Victorian type society i.e. one that aims to raise the average level of the society as high as possible, then the first kind of society will lose that competition e.g. America from the 1960s onwards.

  6. Niels says:

    From the Abstract: “according to a neutral trait, where trait is simply a direction in a high dimensional space, for example conscientiousness or intelligence or aggressiveness or earnings potential. ”

    It is a bold claim that intelligence or aggressiveness or earnings potential are neutral. It is also a claim that is not supported by the rest of the paper. Why don’t you just delete the examples completetly?

    • misdreavus says:

      Physicists love to construct scientific models that represent a simplified version of reality, just to establish some first principles, and then modify them as they see fit for the purpose of rigorous analysis and prediction of future outcomes.

      Yes, there are no spherical cows in nature, but who cares? There’s no such thing as totally random mating in any population, either, yet population genetics remains useful to this day. This is a strategy that biologists ought to be implementing on a regular basis. Yet sadly they don’t.

    • harpend says:

      Thanks, I rephrased the abstract to make it clear that these are the sorts of traits that might be relevant but saying we made no suggestion that they are neutral.

  7. The Dell Curve, should be bell. (Still reading and enjoying)

  8. Andrew Sabisky says:

    Perhaps chronotype would be a better example of a more truly neutral trait that is assortatively mated for?

    • harpend says:

      Perhaps. What is chronotype?

      Thanks

      • Andrew Sabisky says:

        Morningness-eveningness aka circadian rhythms (are you a lark or night owl?). Chronotype is significantly heritable (circa 50% from memory) but it seems intuitively unlikely that either morningness or eveningness is an adaptive trait. There’s not much research on ethnic differences in this area but they appear to be negligible. Loose genetic castes of larks and owls have, I guess, probably emerged because of assortative mating, which does appear to occur for chronotype (http://www.ncbi.nlm.nih.gov/pubmed/22044180)

  9. ziel says:

    I found the paper quite interesting, compelling, and accessible.

    A couple typos:
    “Unfortunately for our model of assortative mating the analogous accounting is very difficult
    to get right so we study instead an analogue of heritability that we call h, is the fraction
    of matings that are assortative.” I think you should leave out the “is” after “call h, ” or insert a “which”.

    4th paragraph, 2nd sentence in “Applications” section – “The are serious…”

    While reading I was curious about the effect of regression to the mean and didn’t find it mentioned. For example, would it tend to mitigate the impact of assortative mating at all? Would its effect be too trivial to the impact? When would the populations transition from regression to the new mean? Or is it completely irrelevant (indeed so irrelevant as to not even be worthy of a mention)?

    • harpend says:

      “While reading I was curious about the effect of regression to the mean and didn’t find it mentioned. For example, would it tend to mitigate the impact of assortative mating at all? ”

      It is an important issue but the analysis in this kind of model gets so messy that we are doing an end run around it with our h. With regression to the mean the change due to exchange between classes is simply discounted by regression to the mean. But how to do the accounting of the variances and covariances induced by our process is right no above our heads.

      Our h is the fraction of possible assortative matings that actually occur. So with h=.4, 60% of mates come from the tail of the neighbor distribution and 40% are just random from the same group. This mimics heritability of .4, keeps the moments accountable, etc.

  10. SpaghettiMeatball says:

    Henry, off-topic question, but how accurate are ideas in this post: http://majorityrights.com/weblog/comments/the_evolution_of_blond_hair_and_blue_eyes_among_nordics/p100Read/P100/

    and Peter Frost’s ideas on the same issue in your opinion?

    • SpaghettiMeatball says:

      Also, a good question is how “crazy” are the people on some of these HBD sites?

      • misdreavus says:

        The #1 intellectual in the HBDsphere is Mencius Moldbug. That right there tells you everything you need to know about this movement. LMAO!

        “Dark enlightenment” my left foot, more like “dark embarrassment” if you ask me.

      • panjoomby says:

        i for one am quite looney on everything except HBD issues.

      • Sandgroper says:

        Barking.

      • harpend says:

        “Also, a good question is how “crazy” are the people on some of these HBD sites?”

        I see that your question set off a discussion of Mencius Moldbug, a site I have never read. I have run into sites that are full of people whom I would not wish to have for neighbors. The people and sites I associate with “HBD” are Razib Khan, Steve Sailer, John Derbyshire, Bruce Charlton, hbd* chick, Satoshi Kanazawa, Jason Malloy, Peter Frost, and so on. These are all worth following. None of them are crazy or apparently crazy. The amren website is worth an occasional glance and Jared Taylor is a gentleman and an honest fellow. The posts on amren on the other hand sometimes are meaner and snarkier than what I want to read.

        The other problem with much hbd writing is that authors confound race and class or something else. The sociology in toto of the US Black population is pretty disastrous but we all need to distinguish between Black people and Black underclass people. Children of Black lawyers in Georgetown are likely not out on the streets punching random passersby.

      • JayMan says:

        @harpend:

        “The other problem with much hbd writing is that authors confound race and class or something else. The sociology in toto of the US Black population is pretty disastrous but we all need to distinguish between Black people and Black underclass people. Children of Black lawyers in Georgetown are likely not out on the streets punching random passersby.”

        My wife agrees. And so do I…

      • Pincher Martin says:

        “Also, a good question is how “crazy” are the people on some of these HBD sites?”

        They’re crazy, but not numerous. If HBD ever becomes popular, however, you should expect their numbers to multiply.

        But crazy people get involved in nearly everything, including mainstream political movements, so I don’t know why the respectable members of the HBD community should be more responsible for their loons than other groups are responsible for theirs.

        In fact, I would bet there’s a pretty strong correlation between the growth of an ideology or meme and the number of crazies who attach themselves to it in some disreputable manner. If that’s the case, then the number of loons who linger on the periphery might be a sign of that idea’s current strength in society.

    • misdreavus says:

      I dunno what Greg thinks. But that entire website is revolting. Not because of its “racism” (I don’t give a damn about that), but because the authors are such incorrigible nitwits. I shouldn’t even have to explain why. Just read some of the fine “literature” they have to offer — the Ahnenerbe couldn’t have done a better job if they tried. (Yes, they are goddamn Nazis, and I can actually prove it.)

      This is neither here nor there. But J Richards, by the way, left majorityrights.com in a rage to establish a new website dedicated fully to the purpose of “eradicating the Jewish problem” — I believe it was called “judenfrei” or something along those lines. (The site is since defunct, but I believe you can retrieve it again through the internet archive.) Some of his most memorable claims include the notion that Ashkenazi Jews haven’t really been selected for higher intelligence, but rather a extreme prediction for criminality, and that this fully explains their economic and social ascendancy in most Western nations. In other words, that IQ difference is just another conspiracy by them Jooz who control Washington, academia, and the Fed.

      And people wonder why “HBD” has yet to gain any mainstream acceptance in American society. Perhaps this explains part of the trend. You’ve got bona fide Nazis here, religious insurrectionists there (idiots who think they are more Catholic than the Holy Pontiff in Rome), people who subscribe to the masculinist counterpart to radical feminism, Southern secessionists, paleocons with an axe to grind against everyone else, and 19th century amateur anthropologists. That leaves _who_ exactly with sane or rational motives?

      There are a few.

      • ziel says:

        I’m fully sympathetic to the notion that the left part of the bell curve should be insulated from the findings of HBD. I know a number of such individuals whose crude prejudices are are informed by real-world interactions. But the last thing they need is scientific confirmation of their biases.

        But in an enlightened society, one would hope that the further right-side of the bell curve would have a grasp of these concepts and would craft careful policies to deal with reality in a humane and productive manner. You’d hope to see smartly designed quotas, restrictive immigration, the building of strong communities, and steps to greatly reduce fecundity among the worst elements (a policy I’d think would be a lot easier than it sounds).

        But instead among the elite we find status-seeking snark battles and vote-buying pandering. And it’s a mostly asymmetric battle – nearly unlimited direct rabble-rousing on one side of the HBD debate while the other side plays off indirect metaphors. It’s a big mess. Sites like Majority Rights merely take advantage of the vacuum in the discussion to counter the Sharptons and Piers Morgans in an equally ignorant voice.

      • SpaghettiMeatball says:

        Yeah, I know. Leftist crazies might be entertaining, but they have nothing on the other side.

      • SpaghettiMeatball says:

        My favorite line from the whole post: “Black Africans would appear to have been in a position to improve their looks, too, given their high rates of promiscuity, but like their abysmally low IQ, they do not seem to have evolved a better aesthetic sense, and retain some of the most primitive facial features around.”

        Hmm, so getting boners depends on your IQ now. Something I didn’t know.

      • JayMan says:

        “And people wonder why “HBD” has yet to gain any mainstream acceptance in American society. Perhaps this explains part of the trend. You’ve got bona fide Nazis here, religious insurrectionists there (idiots who think they are more Catholic than the Holy Pontiff in Rome), people who subscribe to the masculinist counterpart to radical feminism, Southern secessionists, paleocons with an axe to grind against everyone else, and 19th century amateur anthropologists.”

        All very true.

        “That leaves _who_ exactly with sane or rational motives?

        There are a few.”

        Ummm? :p

      • ziel says:

        SpaghettiMeatballs – now what you’ve done is engage in the very kind of pointless snark I was referring to. You quoted a risibly stupid comment from that ridiculous blog, but somehow completely failed to understand it. Nowhere does it remotely claim that “getting boners depends on your IQ ” – it doesn’t say “as a result of their abysmally low IQ” but it says “like their abysmally low IQ” – there’s no cause and effect implied – it’s a simile, not a syllogism. It doesn’t make any sense, but in no way says what you’re claiming it says.

        But that is exactly the kind of snark that the so-called intelligentsia uses in what passes for discussion on this topic – and they will no doubt use some similarly non-sequiturian attacks on Greg and Henry for this paper.

      • harpend says:

        “In other words, that IQ difference is just another conspiracy by them Jooz who control Washington, academia, and the Fed.”

        It is worse than this. Apparently the world is a cube with 4 sides but we only perceive one of them. The jooz, somehow, control the other 3 so they have better access to our money. See http://www.timecube.com .

      • Toad says:

        idiots who think they are more Catholic than the Holy Pontiff in Rome

        Not hard to do.

      • Henry, That site is a really great find. I love this: “Cubicism transcends and disproves Theism Creation.”

        I mean, who knew?

        I get comments showing up on old threads of my blogs with some of the weirdest theories to explain the world. I’d like to see someone collect a lot of these sorts of rantings. Then analyze them (and perhaps interact with their authors for additional data collection) for signs of how many of the people are mentally ill versus how many just have a really bad case of the Dunning-Kruger Effect combined with a need to explain the world on their own. What causes these viewpoints?

        I know some people who have very compartmentalized nuttiness. Incredibly sound on most subjects. Nuts on a select few others. Those types pique my curiosity. How does this happen?

      • 420blazeitfgt says:

        @misdreavus – I have wondered for a while why you don’t blog somewhere

      • misdreavus says:

        “misdreavus is a homsexual”

        no duh, you nutjob.

        any more dirty secrets you’d like to expose here before your IP gets banned?

    • SpaghettiMeatball says:

      I know…I know…don’t be autistic.

    • harpend says:

      That post is a bit overboard but Frost as always is innovative and rock solid. My problem with his enthusiasm for sexual selection is not that I doubt it but that I don’t see a way to test it.

      Frost is always great value and always worth reading.

      • SpaghettiMeatball says:

        My only quibble is that he uses old maps from the 50s (freq. of light hair and eyes, Beals & Hoijer, 1965) to describe hair/eye color diversity in Europe. I think this can be done much cheaper and more accurately nowadays, with an internet survey.

        Maybe make a new map, and correlate the %blond hair with %”Hyperborean” ancestry? I don’t think there will be surprises there, but at least it is going somewhere.

  11. Jason says:

    Pg 8 “How do the class differences in genes her compare” (here)

  12. Karen says:

    Mean stature would be 70 inches if the population consisted only of males. Then there wouldn’t be any future evolution at all.

  13. jb says:

    Lewontin emphasized that 15% was a small number implying that human differences were small and of no significance but he had no basis for adding such a politically motivated and senseless statement at the end of an otherwise fine and pioneering paper

    Given the outsized and undeserved influence of Lewontin’s assertion, this is a very important sentence, and I think it could use refining. A word like “senseless” seems intemperate, and gives the impression that perhaps you are making your own politically motivated attack on Lewontin. FWIW, here’s my best shot at rewriting it:

    However at the end of his otherwise fine and pioneering paper, Lewontin asserted that this 15/85 ratio implies that human differences must be small and of no significance. Although widely cited, this claim is unsupported by Lewontin’s results, and unfortunately gives the impression of being politically motivated.

  14. j3morecharacters says:

    Some comments (take it or leave it)
    1. The part about anabaptist sects has no scientific basis. Had anyone studied some inborn quaity that make them stay in the sect? Or you just presume must be such quality? Regarding their presumed genetic tendency to have “many” children, is it really genetic? Only two or three generations ago Ashkenazi Jews in Russia had many children, yet today they have one child maximum. The same with Chinese and even Massachusetts WASPs. Having many children doesnt seem to be genetic.
    2. Historical and existing castes did not seem to have originated by a differential mating process. Mostly they are foreign groups that inserted themselves in an existing population. Japanese samurai may have been different, but they dissolved as soon that the social structure changed.

    • JayMan says:

      @j3morecharacters:

      “1. The part about anabaptist sects has no scientific basis. Had anyone studied some inborn quaity that make them stay in the sect? Or you just presume must be such quality? Regarding their presumed genetic tendency to have “many” children, is it really genetic?”

      All human behavioral traits are heritable. That doesn’t mean that will remain stably expressed, particularly in the face of changing environments…

      • gcochran9 says:

        You beat me to it. Yes, most psychological traits are fairly heritable. That’s what you would expect for the tendency to fit in with Amish society – so with a fair amount of voluntary defection for 10 generations, you’d expect them to get plainer. This is obvious, and I’ve mentioned it before, but I’ve never seen anyone else notice it. If someone wanted to flesh this out, he’d gather up all the genealogical and defection data and estimate breeding values for plainness. You could do the same for fertility – that has been done for the French Canadians, and indeed it looks as if there was selection for greater breeding value (in a particular non-modern environment) there.

        All ag science.

        Like I said, every society selects for something. As I understand it, the preferred view among social scientists is that no society selects for anything.

      • The fourth doorman of the apocalypse says:

        Like I said, every society selects for something. As I understand it, the preferred view among social scientists is that no society selects for anything.

        Including, say, forms of religion …

    • little spoon says:

      ” Only two or three generations ago Ashkenazi Jews in Russia had many children, yet today they have one child maximum. The same with Chinese and even Massachusetts WASPs. Having many children doesnt seem to be genetic.
      2. Historical and existing castes did not seem to have originated by a differential mating process.”

      It seems before in most societies, a very high percentage of people got married and tried to have as many children as possible. To some degree, fertility must always be selected for selected for, but the desire to have children was probably not as big of a factor on the outcome of most surviving and reproducing offspring in centuries past because of restricted choices (many societies didn’t even have the option of religious celibacy for women). But today in the developed world, the limiting factor in the amount of children people have is usually the amount of children people want to have. This is especially true for those in mainstream society.

      Over the next few generations, I think we will see desire to have children selected for more often. Meaning that assuming resources remain plentiful as they are now, I think hundreds of years from now those choosing not to have children will be a smaller portion of the population simply because that mentality will be selected against every generation.

    • harpend says:

      I recommend Jayman’s post linked in his post here about the reality of inductively discovered traits. IQ is a trait but athletic ability is not because components of what we want to call athletic ability are not correlated with each other–balance, coordination, strength, endurance and such are all pretty uncorrelated.

      “Historical and existing castes did not seem to have originated by a differential mating process. Mostly they are foreign groups that inserted themselves in an existing population. ”
      Greg tells me that there were nascent castes in India for a while of Vhs and Betamax repairmen separated by strict caste rules.

      • The fourth doorman of the apocalypse says:

        athletic ability is not because components of what we want to call athletic ability are not correlated with each other–balance, coordination, strength, endurance and such are all pretty uncorrelated.

        Doesn’t that just mean that there are are several different traits that can be selected for.

      • little spoon says:

        “Greg tells me that there were nascent castes in India for a while of Vhs and Betamax repairmen separated by strict caste rules.”

        Both did better than the Laser Disc repairman line.

        In India, it would seem that marriage within castes continued long after Vedic Aryan invaders looked like a separate group of people. The caste system also seems far more intricate than pure geographic origins of these groups would require.

        In Europe, I would agree that anything resembling a caste seems to have a separate ethnic origin (basques, gypsies, jews etc) but in India there are known cases of castes that emerge from political or religious disagreements etc which separate a once intermarrying caste into multiple groups etc.

      • harpend says:

        Doorman asks “Doesn’t that just mean that there are are several different traits that can be selected for.”

        Sure, but selecting for more than one thing at once can slow the whole process to a crawl depending on the genetic correlation between what you are selecting. If the genetic correlation is negative you might increase one but decrease the other. Think for example of selecting humans for dark skin and blue eyes at the same time. You might end up with people with lighter skin or darker eyes at the end, depending on the genetic covariance between the traits.

      • j3morecharacters says:

        Greg is right. I heard that a VHS repair man would not allow the shadow of Betamax man to fall on him. If it did, he had to purify himself by immersion in the Holy Ganga, or move to Los Angeles and wash in the Holy Sacramento River.

    • Greying Wanderer says:

      “Having many children doesnt seem to be genetic.”

      I don’t know if it’s been replicated but there was a study claiming a fertility sweet spot around the 3rd-4th cousin spot. Wouldn’t that be a very simple mechanism for declining average fertility among a randomly assortative endogomous group simply from their population numbers increasing and their average cousinage moving past the sweet spot i.e. still genetic but not in the usual sense.

  15. Simon in London says:

    pg 13 last para “too course for our purposes” – should be coarse.

  16. Greying Wanderer says:

    @Little Spoon
    “Can you explain what HBD chick’s theory about cousin marriage is and how she thinks it affects societal outcome?”

    My paraphrase not hers but

    That the average level of relatedness in a population matters and that the *pattern* of that relatedness matters greatly i.e. if you have a society at one extreme which is split up into lots of extended family alliances where everyone within the alliance is closely related to each other but not to the rest of society that society will be (or become) completely different to a society at the other end of the extreme where everyone within it are relatively equally but not necessarily closely related.

  17. panjoomby says:

    your math(s) no doubt included REGRESSION TO THE MEAN:) you might mention that! indeed, without regression to the mean, assortative mating on a highly heritable trait would yield group separation even faster & wider, baby!! …also, no love for the word “homogamy?”
    btw, bravo – great work! more, please!
    also include more Amish stuff – pix of hot Amish Kelly McGillis, etc.
    so, are the Amish assortatively mating for beard-cutting-off behavior yet?
    PS – i grew up near where Gregory C. did — ever get to Arcola & see Rockome Gardens? Fine place & very fine people. odd grammar, tho: “smear me all over with jam a piece of bread,” etc.

  18. panjoomby says:

    we moved to C-U from NY — in C-U we took all our NY family visitors to Rockome gardens. we midwesterners are used to ’em, but our NY relatives found our Amish neighbors quite exotic 🙂
    didn’t A. Jensen do some work on assortative mating (husband/wife IQ)? perhaps i merely remember him mentioning it in an article… I’d hazard a guess that the vast majority of your commenters are NOT crazy, btw.

  19. Greying Wanderer says:

    Don’t sulk, the blank slate nonsense lasted 100 years and did massive damage which is quite a good result for something that is so obviously nonsensical.

  20. I wrote an essay once on my placement in the Dark Enlightenment network: http://educationrealist.wordpress.com/2013/04/28/the-dark-enlightenment-and-me/

    because I was a tad nonplused–not embarrassed, but just surprised–that I was heavily read by HBD folk. It makes sense, really, since Steve Sailer was the first blogger to talk about me. But I think of myself as a teacher who writes about ed policy and teaching. Jayman, this site, hbdchick, the rest, I don’t get the science. I don’t care about the cause of the IQ difference, nor do I really care about the cultural differences.So yes, I’m totally aware of the risks of writing about cognitive ability and race, which is why I stay anonymous. But I not only limit myself to writing about education, I genuinely don’t much care about the “why” and the “how” of differences and heritability. I doze off when y’all start talking science.

    But I also had a very telling conversation in the comments of a recent post http://educationrealist.wordpress.com/2013/11/30/not-why-this-just-why-not-that/#comment-4787

    A commenter said: “But cognitive difference arguments are essentially statements that blacks are not equal to whites (and of course other races/groups have differences as well, but they are not as important). It would require overthrowing a pretty basic assumption in Western society (that all human beings are equal) to state, and act upon, cognitive difference arguments.”

    That comment didn’t even register with me; I was focusing on the first part of his post. Happily, another commenter saw it and remarked on it. I reread, said whoa, cowboy. Back up.

    This guy was really disgusted with me, thought that I was copping out.

    The long, roundabout point (I have no other kind): far too many people genuinely equate IQ with superiority. Many of them are blank slaters, which seems contradictory but isn’t. They get upset at the very statement that races have different IQs on average because they automatically think that smarter=better. But others of them are dark enlightenment folk, and to them, the dark enlightenment means reclaiming the upper hand, of restoring a better order. Not restoring slavery or anything like that, but understanding that multiracial societies can’t work and moving back to homogeneity. And then yeah, there’s something about Jews which I never get.

    Of course, what do we do, in a diverse society, if we acknowledge these differences? I write about that in terms of education, but I think others are so busy taking on the denial of blank slaters that they don’t really think about what happens next. Dark Enlightenment folk are on that next step already.

    • Hi teacher, IQ and superiority: Have a look at this chart by Linda Gottfredson about IQ assorted things that people do with their lives. (and same chart here.

      The concern of many people is that a community with lower average IQ really is worse by many objective measures. Does that mean that people with higher IQ are superior? Depends on how you define superior. Loaded word. But do you want a society that has more unemployed, chronic welfare recipients, criminals, and the like? Or are you indifferent? Or strongly opposed perhaps?

      • I answered that point in the conversation.

      • Hi teacher, I read all your comments on that thread. One of your own comments from that thread says (incorrectly):

        No one knows really, what we can achieve if we try to educate people with low IQs

        You underestimate what the psychometricians have figured out. Seriously. On the one hand you’ve said lots of things that suggest you are familiar with the main findings of psychometricians. Then you say what I quote above. I do not know how to reconcile the two. You also seem to discount your own experiences with kids you teach who just can’t retain that much understanding.

        Have you read what psychometricians say about who can learn what?

      • The fourth doorman of the apocalypse says:

        No one knows really, what we can achieve if we try to educate people with low IQs

        A teacher I know uses the following analogy:

        Since pretty much all kids in the area where we live want to learn to drive, and actually do learn to drive, all we need to do to teach them algebra or rocket surgery is help them find the motivation.

        I think this is a flawed analogy because driving is a relatively simple task, cognitively, and takes advantage of existing capabilities we have (like paying attention to external queues, estimating the speed of oncoming vehicles, figuring out the intentions of other drivers from their behavior, etc) while algebra and rocket surgery (which are not really in the same class) are cognitively very different.

        There might also be an interaction with the Visual Wordform Area some claim that some people have in their brains.

      • Not sure what to tell you, Randall, except none of that has anything to do with what I’m talking about. And I don’t know why you call me “teacher”, but it squicks me out.

  21. IC says:

    This theory of assortative mating not only explains castes or class formation in a human population might also explains speciation of animals in a shared enviroment. You do not need isolation to create new species.

  22. If the assortative mating is at least partially responsible for the shrinking middle class then shouldn’t the standard deviation of white IQ be going up? Also, shouldn’t the distribution be looking less like a bell curve? What is happening to the distribution of white IQ in America? Anyone know?

  23. Typos and wording:
    Do you really mean to say “for to” here? assortative mating for to a neutral trait

    The use of “patterns” and then “pattern” in these two sentences is confusing between they sound like they are referring to the same thing. The second “pattern” reference connects back to a bigger point.. Suggest “customs” or “behaviors” or something else for the “social patterns”: Henry, you are an anthropologist. Got a different term that works here?

    Some of their unusual social patterns have biological significance,
    and it is those that we will discuss. We think the pattern we discuss may have often occurred
    in human history.

    I also think the use of pattern (singular) here is inconsistent with patterns above with social patterns:

    due to their unusual social and reproductive pattern.

    Again here:

    their social pattern probably drives

    You have a problem with conflict/conflicts in your discussion of biometricians and Mendelians. Either go consistently singular or consistently plural.

    Does “its” refer to the Human Genome Project? Doesn’t seem like it. Does the promise refer to the future only? We already have thousands of sequenced full genomes, no? The sentence needs some rewording.

    its promise to deliver thousands to hundreds of thousands of complete human genomes

    for examples -> for example

    Journql -> Journal

  24. RS says:

    > Morningness-eveningness aka circadian rhythms (are you a lark or night owl?). Chronotype is significantly heritable (circa 50% from memory) but it seems intuitively unlikely that either morningness or eveningness is an adaptive trait.

    It’s been suggested that having mixed chronotypes in a group facilitates keeping defensive watches (whether regimented or ad hoc). Highly plausible. One generally hears of primitive (non-urban) groups raiding pre-dawn, but it would be incredible if they didn’t mix it up a little by sometimes coming at midnight.

    A Yanomamo ‘lark’ may not be manning a watchtower with infrared binoculars — he could just be chilling in his hammock. But he’s awake, and hearing noises in the perimeter of dead branches that Yanomamo pile up around their village. They have dogs, but the Yanomamo lark is more sophisticated in assessing the situation than the dog is. The dog’s olfactory sense is >1,000x superior, but he would score poorly on a pop quiz on knowledge of recent political currents affecting his village.

    Urban groups have had to keep watch too, at home or on expedition, so it would make sense that they retain the trait.

    This is of course group selection, but if the effect on the group is large and the hit to the individual is zero to pretty darn low, it’s gonna happen. Here the effect on the group is ample. Not for nothing has falling asleep on military watch sometimes been punished with execution.

    Also, don’t cows need an early milking, or something? –At least highly-bred, high-producing modern-day cows. There’s also guarding herds from wolves or thieves. And taking care of infants in the night. So there could be other applications but I’d think the military one is much the most important.

    • Richard Sharpe says:

      Modern dairy cows produce so much milk that they need to be milked twice a day. Typically around 6AM and 6PM (or some such pair of times separated by 12 hours.)

      They are no respecters of daylight saving time, either.

  25. dave chamberlin says:

    I love your phrase “boiling off” to describe how societies change genetically through time. Since the wide use of contraception combined with the transformation of children from an asset on a 19th century working farm to a monetary hardship to parents today there has been a rapid boiling off of adults whom chose not to be parents. This must be radically changing people genetically through time and I don’t think anybody is talking about it. I thought I would bring it up because I find it interesting and noteworthy.

    I do not doubt that assortative mating has not changed through time in regards to average years of education but I think this misses an important kind of new assortative mating. Women and men of more than a 2 or 3 standard deviation IQ above normal are far more likely to be in close proximity during their mate selection years and thereby more likely to chose each other as mates. This has occurred in the last few generations thanks to two changes in society. The upward mobility afforded to the highly intelligent thanks to the college entrance exams becoming a large determinate of whom gets into the best colleges and then proceeds on to the job market requiring the smartest people and secondly the removal of sexism which blocked women from joining men in these colleges and the follow up job market. I have no scientific data to back up my contention so that means i have no proof. But wouldn’t it be both fun and productive to find out. If ever you two need free assistance in conducting any further studies you have my E mail address so don’t hesitate to ask as I find your work, ramblings, thoughts, and rants to be both entertaining and illuminating.

  26. Brett says:

    I’ve been working through some of the math, and I believe you should be able to treat the problem more exactly using a discrete rather than continuous model of “merit” distribution, treating it as the sum of a large number of alleles of small effect. This gets you a binomial distribution of large n, which is nearly identical to a normal distribution. You can then do exact calculation of the distribution of descendants of truncated binomials or any arbitrary population distribution. I think I can also look at alternative assortative mating rules by convolving the population distribution with a function representing mating preferences. I’ll email or post here again once I finish cooking Christmas dinner and can finish the mathematics.

    • vaniver says:

      I did something similar, which I’ll post soon (I think I want to write the accompanying code and generate some graphs). My impression is that it comes out as a more transparent computational model, and it’s not very useful for getting exact results in the continuous case (i.e. taking the limit as the n parameter of the binomial approaches infinity).

      Now, a more transparent computational model is nice, because it lets you adjust all sorts of parameters and see the effects. For example, you can express the mating preference between any two levels as a symmetric matrix, and you can pair this with an explicit phenotype model to investigate heritability more precisely. What would be really nice is to end up with a state space representation and to be able to algebraically calculate the trajectory, but I think the dynamics are nonlinear- which means that we probably ought to stick with computational models. But it’s been a while since I looked hard at this sort of statistics, and someone may have come up with a clever trick that I’m not aware of.

  27. panjoomby says:

    @dave chamberlin & JayMan: each of dave chamberlin’s paragraphs is worthy of an entire book, as JayMan aptly points out & provides data toward. please get together & write those books (or make them into one big book, so it will be cheaper:)

  28. Anonymous says:

    The distinction with England / France is that their aristocracies are ancient. A well-bred Englishman has a 1200 year aristocratic line extending prior to the Conquest. If you ever met someone like that it is plainly obvious who they are after a five minute conversation. The problem is that many policies have crippled our best families.

    There were genocides against the French aristocracy, German-Jewish aristocracy and the Southern plantation aristocracy (refugee cavaliers). High taxation rates or wealth confiscation (like we now have in France) are another form of anti-aristocratic genocide. Catholic countries are hobbled because their best and brightest aristocrats were absorbed into the church and their lines diminished.

    Democracy itself is an anti-aristocratic institution that is inherently unsustainable because the ancient traditional ruling class is supplanted with a new ruthless class of narcissists able to game the voting system. This started with President Jackson. The great victors are weak men with strong mothers and no fathers (Clinton, Obama) rather than an established aristocratic class loyal to tradition.

    Far east cultures failed to develop aristocratic lineages since they passed wealth to all of their children and their agricultural traditions diminish individuality. You don’t find as many with traditional “noble” traits: high intelligence, natural leaders, agreeable personalities, natural athletic horsemen, large stature, long term focus, high creativity, individual initiative, steadfastness, ability to both serve loyally and to exercise power with restraint and without mania. Think George Washington.

  29. Anonymous says:

    Comparison of English/Confederacy upper caste, aski jews, and the rest from 1000-1860 (40 generations)
    # of Generations (ballparking)
    Literacy: 30 (WASP elite), 40 (jews), 1 (rest)
    College/higher ed: 15, 3, 1
    Mayor, Colonel, etc: 15, 0, 1 (jews held no gov’t offices)
    large business: 30, 10, 1

    So, ancient English/Confederate aristocratic classes & jews spent the last 1000 years busily learning and running enterprises while the rest of the world’s ancestry was largely in the fields. WASP upper castes had generations of breeding for running gov’t enterprises (no wonder they conquered the world).

    In the West, French, Russian, Prussian, Polish aristocracies were all killed off or they lacked rigid class structures to produce a distinct bloodline.

    So, a “stereotypical” WASP upper gentry descendant circa 1900 might have in his bloodline….
    Literate since 1200
    Attending university since 1600.
    5 “knighted”
    20 running large scale enterprises/manors
    10 mayors, colonels, etc.
    And they often had 10+ kids in the 19th century.

    Is there any comparable large population group in the world with a similar quality bloodline? These bloodlines produced a robust bourgeoisie that was the basis for democracy in the Anglosphere. No wonder why the English Left insists on immigration to breed what remains of this group out.

  30. JediWonk says:

    The link proffered to this draft paper:

    https://dl.dropboxusercontent.com/u/163075/Oakland.roughdraft.pdf

    is now “404”-ing for me.

    Fortunately, I PDFed it up back when…

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