Truncation selection?

In some cases, fitness depends on an absolute standard, but in others it depends on a relative standard.  Suppose someone throws you out of a fourth-story window: what matters is not whether you suffer less damage than others, but whether you are actually tough enough to survive the fall.  Gravity doesn’t grade on a curve. On the other hand, there are many situations in which the world does grade on a curve.  In a famine, one where there’s only enough food for half of the population, you only need to be in the top half to survive.

Or, are you fast enough to out-race the tsunami [absolute standard], or fast enough to outrun your rivals? [relative standard] .

Suppose that we ranked people by some kind of genetic merit and liquidated those that were more than a standard deviation below average. This turns out to be a very efficient way of reducing genetic load.  Each liquidated individual carries significantly more deleterious genes than the population average, and so truncation selection reduces the number of deleterious genes passed on to the next generation – enough to keep up with a fairly high mutation rate.   Of course all this also depends on how fitness varies with the number  of deleterious mutation [is it really multiplicative?] , but that’s a different can of worms that I won’t address right now.

The question is, to what extent has natural selection in humans been truncation-like? And has it been equally truncation-like in all populations?  Any variation would cause local differences in the efficiency of natural selection, which would (if long continued) cause local differences in the amount of genetic load, and possibly local differences in the flavor of genetic load, as well.

Case 1: just enough food is produced to feed the existing population, and production doesn’t increase with the population. Resource-limited.  The average family has four kids.  The half of the new generation with the most moxie [broadly defined, involving various forms of interpersonal competition] survive, the rest starve.

Case 2:  There is plenty of food, but there is a virulent infectious disease that kills half the rising generation. This disease  gets worse with increasing population density, so it always limits the population – food stays abundant.  What matters is a quite narrow kind of moxie – the alleles that influence the course of that virulent disease. And if your defenses keep you from being infected,  that’s as good as it gets.

Case 3:  Half of each generation is killed by meteorites.  Genes are irrelevant.

I don’t think that any human population is a pure case.

The overall intensity of selection can also vary – some populations may have three kids and lose one, some may have four and lose two.

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25 Responses to Truncation selection?

  1. Cases says:

    1. People get better at productivity or stealing, depending on how good society is at making crime not pay. Fertility and disease resistance matter less: you can’t feed extra kids and disease frees up food for more. Europe, Japan, China, and other places with low disease burden.
    2. People get better at disease resistance, at the expense of other capacities. The tropics.
    3. Fertility is the only way to improve fitness since death is not malleable. Invasive species, Quebecois.

    “This disease gets worse with increasing population density, so it always limits the population – food stays abundant.”
    How density-dependent are the major tropical killers?

    If we cut the frequency of deadly famines from once a lifetime to once every two lifetimes, does this cut strength of selection in half and double genetic load?

  2. Also cultural

    “West of this line, the average age of marriage for women was 23 or more,[3] men 26, spouses were relatively close in age,[4] a substantial number of women married for the first time in their thirties and forties, and 10% to 20% of adults never married.[5][6][7] East of the line, the mean age of both sexes at marriage was earlier, spousal age disparity was greater and marriage more nearly universal.”

    “The Western European pattern of late and non-universal marriage restricted fertility massively, especially when it was coupled with very low levels of childbirth out of wedlock.

    • jqhart says:

      Might not this pattern prior to the 20th century be primarily genetic rather than primarily cultural?

      • Greying Wanderer says:

        It might be but the main point is (imo) that one way or the other malthusian buffer zones can be created and they can work alongside all the disease and/or starvation e.g. late weaning, female infanticide (fewer total people on a piece of land but with the same number of defenders) or hajnal-style late and partial marriage.

        (Also if it started culturally the cultural selection would shift the genetics over time anyway as those people who were favored by the cultural selection outbred the ones who weren’t.)

  3. OK folks, it’s going to have to be computer simulated. We already have too many factors.

  4. dearieme says:

    “computer simulated”: I used to do lots of that. Tell me the answer you want and I’ll ‘predict’ it. Just like a Climate Scientist, really.

  5. The fourth doorman of the apocalypse says:
  6. Georgia Resident says:

    Case 2 sounds like sub-Saharan Africa.

  7. -Case one sounds like the starting point for a science fiction story. Try to breed the population for meteorite resistance and see what happens. Presumably something like the Teela Brown gene.

    -The ancient Greeks routinely exposed deformed and/or unwanted babies. I wonder if that had any overall effect on the genetic makeup?

    -How about the reverse? Let’s say, just for example, that a regime decided to eliminate a certain minority that exhibited identifiable characteristics including roughly a standard deviation higher IQ?
    What would be the long term effects on that society? Not that any such thing ever happened…

    • reiner Tor says:

      Let’s say, just for example, that a regime decided to eliminate a certain minority that exhibited identifiable characteristics including roughly a standard deviation higher IQ?
      What would be the long term effects on that society? Not that any such thing ever happened…

      My guess would be that such a minority would control the media and entertainment in the largest industrial power of the world, with a strong foothold in the financial industry and some other industries. This minority might also be overrepresented among the highest ranks of the leadership and the secret police in another very large great power with a brutal and totally lunatic and murderous totalitarian dictatorship.

      I would bet that the regime that decided to exterminate this minority might only do so after the already mentioned largest industrial power in the world got involved in the conflict by supplying large quantities of weapons to its enemies, and suspecting (not totally without justification, but a bit oversimplifying) that this involvement was largely due to the influence of named minority. My guess is that a few years later this regime would be defeated, although not before murdering maybe six million of the minority group with the high cognitive abilities, and this mass murder would ever since have been held up as the epitome of evil, even when the other, already mentioned murderous regime had a higher body count of innocent civilian victims than this regime. But, as I already mentioned, the minority would totally control media in the largest industrial power of the world, so they would mourn their dead a little bit (maybe a hundred times or so) more than the dead of other peoples.

      They might also spread an ideology of blankslatism and multiculturalism (called “modern anthropology”, “Critical Theory”, “modern liberalism”, etc.) at the universities and later media and culture of the greatest industrial power of the world, as well as the whole civilization of the race that built this great industrial power. The country which originally tried to exterminate that minority would possibly ever since be gripped with remorse and would let in an ever growing number of immigrants, in the long run thus exterminating itself in a painless way, just as the greatest industrial power and any other countries in the same civilization would do, all of whom having succumbed to the above mentioned blankslatist and multiculturalist ideology.

      Not that above mentioned things or anything even remotely resembling them have ever happened, or had any chance of happening, but I guess that’s how it would play out.

      • Ilya says:

        @reiner Tor: Being originally from the Motherland, there is this idiom I heard:
        “Если в кране нет воды – Значит выпили жиды.” Your post has a nice steamy whiff of that.

        BUT: I’ve got some good/bad/confusing news for you. The ideology is being spread by a whole lot more people than the “powerful high-IQ minority” inside the largest industrial power of the world. As to the minority itself, the most vocal ones among them in that aspect are the ones tending to have lowest fertility and highest assimilation rate (both cultural and genetic): they like to “lead” by example :).

        I’m not denying, however, their overall high participation rate in the support of such an ideology, but they have a good reason(s), historically speaking. What’s the reason for the rest of the propagandists? That’s right, they had no cohesion to begin with, and by complaining about it, *you* are not changing anything.

        As to the country that originally tried what they tried: fighting on two fronts, including against the emerging greatest industrial power of the world, was a pretty dumb idea, no matter how big the ball was of the guy who thought that importing good-looking Eastern Slavic young women would help with racial betterment.

        In fact, one can argue, the “attempt,” as you might call it, made this whole mess much worse, if not start it altogether.

      • reiner Tor says:

        “Если в кране нет воды – Значит выпили жиды.” Your post has a nice steamy whiff of that.

        Your proverb has a nice steamy whiff of the view that anti-Semitism is a highly virulent yet inexplicable and irrational mental illness based on fantasies totally disconnected from real-life Jewish actions. On the other hand, I am happy that we agree that Jews were vastly overrepresented among promoters of multiculturalism and blankslatism.

        I will ask you whether you subscribe to the view that the mildly totalitarian PC-dictatorship would collapse without heavy support from the media and entertainment industries. It needs a lot of deliberate lies about St. Trayvon Martin, a relative suppression of black-on-white crime (even the meagre coverage we have is having a huge negative effect on the reception of the ideology), a constant supply of role models (from George Clooney through Lady Gaga) promoting the ideology, portraying scores of classical music loving black rocket scientists as well as plenty of evil racist white men in movies, etc.

        The next question I would venture to ask is whether there is or was at any time a Jewish overrepresentation, God forbid, domination in the entertainment industries and mass media. Well, you know, to ask the question is to answer it.

        I would also maybe mention that Jews are not quite lost even outside the entertainment industries, mass media and blankslatist movements (like critical theory, Boasist anthropology, etc.). They are well represented in the gambling, real estate, financial, etc. industries, and are probably among the highest income ethnic groups in the world. This would, by the way, simply follow from them having very high average IQs, for the Ashkenazim one standard deviation above the white gentile average.

        Maybe another fact, which you might perhaps also recognize, is that Jews are not simply rich, but are active in the political process. The largest individual donors to both candidates in last year’s presidential elections were Jewish, just to give you a visible example.

        Methinks that if Jews are a visible and highly influential elite groups, and if things go wrong in the areas where they are dominating, then it would logically follow that people will tend to criticize them. Even if this small essay might get me out of a job if written under my real name and my boss’s attention was drawn here.

      • Ilya says:

        @reiner Tor: “Your proverb has a nice steamy whiff of the view that anti-Semitism is a highly virulent yet inexplicable and irrational mental illness based on fantasies totally disconnected from real-life Jewish actions.”

        Yes, anti-Semitism is a highly virulent mental condition. However, au contraire, it has both a set explanations and a bunch of rationales (I use “rationale,” as the term “rationality” tends to be overloaded and overrated); rationales which most often have to do with jealousy and out-group hatred. It is these that tend to get enveloped into patriotic and fairness type propaganda.

        What you say about “over-representation” is factually correct (as measured in actual number of people from a group adjusted for demographic representation of that group). However, people with the ascribed mental condition take it beyond facts, to be a normative statement, a call for action (as in, “over-representation of such-and-such-group is a bad thing, I/we know better than anyone else what’s bad, so let’s fix it!”). These, nowadays, tend to often be the same people who also whine that certain groups are to be discouraged from breeding and/or living, oftentimes neglecting to check out their own IQ. (Understandably, people who participate in this forum take IQ as the prime measure of someone’s worth in the context of modern civilization, and I don’t have qualms with that particular notion.)

        Your true rationale (and I go out on a limb here), may be different. You rightly accuse the majority of mass-media-influential Jews, the “Joozians,” of siding with blank-slatist ideology. However, I’ve stated that there are very good, historically-justified causes for the Ashkenazim to be adherents of that. What is the cause of the influential goyim? Maybe you could add more info? I’ve already stated the reason, actually: essentially, no cohesion and following self-interest. Everyone looks only after themselves and their own family. And that’s that. (Heck, even among the secular Jews such a thing has become the normal.)

        Some background: In the US-imposed, globalized, dollar-based trade oriented world, the threat of large actual war has never been lower. The reason for cohesion on national level in developed countries is, for the most part, gone. Truth of the matter is that even decent-to-high IQ is no guarantee of prosperity or even comfortable retirement. Forces much deeper than rhetoric and idealism are at work: scaling, automation and outsourcing of labor. Add to that increased urbanization and labor mobility, and maybe you start to see the picture. Even in supposedly growing segments, like software, there is a lot of competition within the global pool of talent. It is the people with very high-IQ and very high motivation, people like the ones who own this blog, that tend to have more luck. The rest of the smarties are not really friends of each other, even though some of them come to this blog to vent their frustrations, and to sometimes mention Jews as the core of their problem. The big “problem,” if you would call it that: large-scale war is not likely, yet there is an oversupply of labor, including for non-physical occupations.

        As one Brazilian once suggested in the comments (but then promptly went overboard with conspiracy babble), the elite (which consists of a *whole lot* of non-Jews, who are still minority, even if relatively over-represented) is interested in its status quo: preserving its position as the elite. One of the best ways, in a strong state, to preserve such a status quo is by preventing a strong opposition from forming. One of the ways to prevent that is by preventing consensus among the non-elites. And one of those ways to achieve it is by diluting their identity/legitimacy of the identity (which, traditionally, has been either religious or national identity, the latter tying with genetic similarity).

        No, I am *not* suggesting a conspiracy. I am saying that it is something that is understood at gut level by the majority of players, including by, albeit in a slightly different way, the kindly daughters of the elite who choose to volunteer in Ghana to demonstrate their amazing reservoir of compassion and idealism and/or live bohemian/hipster lifestyles in the central metropolises (e.g. check out one of Bush’s daughters).

        And the world is moving on. The institutions that are out there to help people in need grant their help irrespective of someone’s IQ or race. In fact, one may argue, maybe being poor is better when one is dumb, when one doesn’t exacerbate his material lack by the deep mental anguish that tends to come along with it.

        Why is someone non-Jewish like Unz not setting up a help-smart-non-Jewish-people fund, to help smart sufferers to survive and breed? After all, Jews (those who value their identity beyond joking about eating matzo-ball soup) often set up various orgs to help out each other based merely on their identity as fellow Jews. Are there a lot of successful Hungarians out there setting up funds to help ethnic Hungarians/Magyars in need?

        It’s all either empty rhetoric or demagoguery, something that has always been and always will be (and, yes, true: nowadays, thanks to TV and effective marketing, public shaming etc. is more powerful than ever, but so what!) Is there anything genuinely new in that?

        As to PC-dictatorship: despite all, this is still a democracy, it’s not yet Soviet Union, so keep talking.

      • gcochran9 says:

        “someone non-Jewish like Unz ”


      • Ilya says:

        @gcochran: it looks like I was wrong to think of Unz as non-Jewish. My sincere apology, and thanks for letting me learn something new (it looks like Unz is not the only one who can’t count their Jews ;-) ).
        I still stick to my overall argument above.

  8. dave chamberlin says:

    Case 4: Quality of life diminishes enough so that people make the choice to have less than replacement level children and those countries that keep on overpopulating end up following the outcome of Case 1 or Case 2. Immigration from Case 1 and 2 countries to the majority of the world which follows the Case 4 scenario is minimized to a smart lucky few.

    • dave chamberlin says:

      But all is not rosy for Case 4 because;

      The meek were supposed to inherit the earth
      But they aren’t the ones who most frequently birth
      It’s those without will
      Who can’t swallow a pill
      whose love of their children is their source of self worth.

      • Ilya says:

        That’s a nice poem.

        I watched two movies yesterday: World War Z and Elysium.

        In Elysium, the perfect little world eventually collapses for “the good of all,” adding more credibility to Dr. Cochran’s intergalactic “manifest destiny” idea as the only way humanity can survive/evolve in long-term.

        World War Z, as silly as the movie was in some way, brings to mind an interesting idea: is (re-)introducing a (potentially mutated) pathogen with a known-but-very-expensive antidote a good way to filter out humanity based on zones of thought?

  9. aisaac says:

    Case 3 is exactly like what happens to a sourdough starter. You start with flour, any flour from the grocery store will do, you mix it with water, and you throw out half of it and feed the other half new flour and water every day or so. Genes are certainly not irrelevant – the fastest breeders, and the ones who can live in an environment created by them, win. Usually the result is a mix of yeast and lactobacillus, which keep it nice and acidic and kill of most potential undesirable microorganisms. You can observe the change over a week or so, as it changes from nasty smelling rotting flour to sourdough.

    It’s also kind of like what’s happening now in human populations in developed countries – big brother takes care of everybody, so selection is relaxed, so the winners are those who breed the fastest. It should be obvious to anyone who understands the exponential function, which could be as much as 1.5% of the population, that this is unsustainable, but it’s been going on for some time now. Even without any external selection pressure, there are still people who breed quicker than others for a number of reasons, and there’s still sexual selection. I would think genetic load would still put you at a disadvantage, at least when it goes beyond the I-don’t-have-the-foresight-to-use-birth-control stage and gets to the nobody-wants-to-fuck-me stage.

  10. Ursiform says:

    The one standard deviation below the mean brought to mind a report I heard on the radio some months back. It was breathlessly reported that a new study showed that one-sixth of kids were well below average on some measure or other. (I don’t recall what the measure was.) As I listened I came to realize that the study had defined “well below average” as being one standard deviation below the mean. I lost interest because there is no practical solution for one-sixth of kids being in the bottom sixth …

  11. Steve Sailer says:

    A big question would seem to be how much selection was done in a non-Malthusian world like in the first example. John Reader’s argument in his “Africa: Biography of a Continent” is that most of sub-Saharan Africa was usually not up against a Malthusian limit. Population was kept down by disease parasites, but also by struggles with other people, _and_ (and this seems to get overlooked by people over the age of ten) struggles with large animals like lions and elephants, which can devour your crop. Reader’s model of prehistoric Africa is one in which people need more people to form a critical mass to drive away elephants and other huge beast. But, too much density leads to infectious disease getting out of control.

    • SpaghettiMeatball says:

      “Population was kept down by disease parasites

      Steve did you read this post carefully? That is one of the factors of selection, in case 2.

  12. That Guy says:

    Case #1 is interesting, makes me think of a few examples:
    1. Levant/Fertile Crescent – with its ancient history of repeated genocides – resource competition drives people to evolve tribal mentality, where nepotism is rife
    2. Sicily – heavily populated since ancient times – tribal/mafia/nepotism
    3. Ireland – repeated genocides and heavily populated for centuries – heavy inter-male competition leading to more Alpha-like characteristics and nepotism

  13. Patrick Boyle says:

    As it happens we may soon experience something like Case #1. We have recently all but abolished want everywhere except the poorest countries. But that will change.

    The capacity for the planet to support humans is going to radically diminish. We have enough land, water, and sun to feed seven billion people in our present day interglacial. When the ice returns that won’t be so.

    I don’t think it will be a natural selection process that adjusts the human population down to the new carrying capacity of a frozen earth. Natural selection is interesting and illuminating but much too slow to really be important in the modern world for emerging problems.

    We will likely have something more like Case #3. Genes are irrelevant.

    See :

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