Local Knowledge

People who grow up in a small town, or an old and stable neighborhood, often know their neighbors.  More than than that, they know pretty much everything that’s happened for the past couple of generations, whether they want to or not.  For many Americans, probably most,  this isn’t the case. Mobility breeds anonymity.  Suburban kids haven’t necessarily been hanging out with the same peers since kindergarten, and even if they have, they probably don’t know much about their friends’ sibs and parents.

If you do have that thick local knowledge, significant trait heritability is fairly obvious.  You notice that the valedictorians cluster in a few families, and you also know that those families don’t need to put their kids under high pressure to get those results. They’re just smart. Some are smart but too rebellious to play the game – and that runs in families too. For that matter, you know that those family similarities, although real and noticeable, are far from absolute.  You see a lot of variation within a family.

If you don’t have it, it’s easier to believe that cognitive or personality traits are generated by environmental influences – how your family toilet trained you, whether they sent you to a prep school, etc.  Easier to believe, but false.

So it isn’t all that difficult to teach quantitative genetics to someone with that background. They already know it, more or less.  Possession of this kind of knowledge must have been the norm in the human past. I’m sure that Bushmen have it.

The loss of this knowledge must have significant consequences, not just susceptibility to nurturist dogma.  In the typical ancestral situation, you knew a lot about the relatives of all potential mates.  Today, you might meet someone in college and know nothing about her family history.  In particular, you  might not be aware that schizophrenia runs in her family. You can’t weigh what you don’t know.  In modern circumstances, I suspect that the reproductive success of people with a fair-sized dose of alleles that predispose to schiz has gone up – with the net consequence that selection is less effective at eliminating such alleles. The modern welfare state has probably had more impact, though.  In the days of old, kids were likely to die if a parent flaked out.  Today that does not happen.

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23 Responses to Local Knowledge

  1. carin says:

    re: “susceptibility to nuturist dogma”

    Educators understood a great deal more about how to educate Johnny and Jill when they lived in small communities. Smarts ran in families, they knew, but they also recognized that occasionally a kid from a smart family was only so-so in intelligence and that once in a while a kid from an average family showed surprising smarts. They also recognized that ambition was a trait that ran in families. Sure, at times kids were prejudged and placed in the wrong classes or the wrong reading groups (remember robins, bluebirds, cardinals?) but it didn’t take but a few days or hours for a teacher to see the misplacement and rectify it by moving the kid. Today, teachers who speak of differences among kids’ innate intelligetoo loudly are ignored. I’ve had innumberable teachers under the age of, say 40 or so, tell me they “don’t believe in IQ” or “if it exists, it’s just a measure of the kid’s family and community environment.”

  2. dearieme says:

    You can learn the same sort of lessons from animals. Have you ever met a farmer who didn’t believe in hereditary traits?

  3. Tso says:

    I just listened to your New Books in World Affairs interview and it made me wish you and Henry would post more often. I’d love to hear a discussion with with Steve Sailer, Razib Khan and others online. Every few weeks I type gcochran into google to read your replies to various blog posts. Perhaps the guy who put up the “World of Greg Cochran” website could gather all of your “rants” and post them here…

  4. Protagoras says:

    How does something being heritable turn into it being genetic in this discussion? There are clearly things that run in families because children imitate and learn from their parents and other relatives.

    Also, in small communities like you describe, the environment is overall more homogenous. Less variation in environment will, of course, mean less effect from variations in environment, and so can potentially mislead one about how much difference variations in environment could potentially make (in cases where it’s more dramatic).

  5. Bob Arctor says:

    “How does something being heritable turn into it being genetic in this discussion?”

    Read the first sentence of this:


    • Protagoras says:

      Previously, I had seen heritability defined in terms of statistical correlations in traits between generations, but I am happy to use your wikipedia definition and make heritability about genes if that is your preferred authority. In that case, my question would obviously be how something running in families made it heritable.

      • Henry Harpending says:

        “Running in families” is way left behind these days. For a long time much of the literature relied on fostered children, e.g. sib or twins or identical twins, raised apart. This of course doesn’t rid us of shared uterine environment effects. These are important in mammals but they do fade away with maturation.

        Recent literature has taken advantage of SNP chips, looking at the relationship between genetic similarity and trait similarity and genetic similarity assessed at a million or a million and a half genetic markers. This literature has repeated just what the old biometricians did at the turn of the century with exactly the same results. Can we predict your IQ knowing your (unknown to you) fourth cousin’s IQ. Yes. “Fourth cousin” is assessed by your genetic similarity at all those markers.

        A good entree is this recent paper based on millions of SNPs and thousands of subjects.

  6. konkvistador.wl@gmail.com says:

    Just wanted to chime in to bring attention to the discussion of this post on Lesswrong:


    • gcochran says:

      I noticed the exchange about the genetics of schiz: lots of confusion. My take is that current data suggests that most schiz iz the result of mutational pressure: possible because it is really many different syndromes lumped together – a grab-bag. The number of loci that can mutate in a way that causes something in that grab-bag is very large. When people do find causal variants, they tend to be rare, generally specific to a particular (and shrinking) family. Average lifetime of an allele of strong effect is something like three generations.

      That said, environmental factors can surely contribute. There is a real but small seasonal pattern, and a real but strong influence of prenatal starvation. The Dutch famine of 1944 and the Chinese famine associated with the Great Leap Forward each roughly doubled schizophrenia in those in-utero at the time. Then again, it’s higher in big cities than in rural areas. 2.4 times more common in Copenhagen than on a Danish farm.

      Selection pressure against schiz is fairly strong today and was likely stronger in the past: people too crazy to farm or hunt generally starved, along with their children.
      Creativity may well be more stronger in unaffected relatives, but I doubt that creativity boosted fitness much in most past environments. While having long conversations with little silver men living behind the wallpaper was in general quite bad for fitness.

  7. gcochran says:

    It is possible to draw false conclusions from the fact that psychological and cognitive traits are similar among closely related people. But it is even easier to draw false conclusions when you don’t know the fact in the first place.

    The variation in family income among students attending public school in a small town is generally larger than in a big city, where neighborhoods are often sorted by income. And sometimes there are sizable cultural differences as well: for example, Amish kids attended my middle school, and I guess you could say that their lives are a little different from the American average.

    Anyhow, the behavioral geneticists think that between-family variation, differences in the way that a family raises raises kids, has little effect on cognitive and personality traits by adulthood – at least within the range of variation usually seen in the US. If one family repeatedly hit their kids in the head with ball-peen hammers, that would be a different story.

  8. Henry Harpending says:

    I grew up in a small town in northern Appalachia and I second Greg’s thoughts and opinions. In The Bell Curve there is a chapter late in the book about small town life, especially about the lack of class differentiation, that was right on the money. Reviewers heaped scorn on this chapter, imagining it to be Murray’s dream. I suspect these reviewers grew up cities or suburbs and could not imagine that what he described could be true.

    There are other differences between country and town folk that may be important in our contemporary political life. Several years ago I was to attend a conference at Southern Illinois University. I met an old friend and colleague at the St. Louis airport where we rented a car to drive to the conference. My friend, as I recall, had grown in a Long Island suburb.

    The rental car was deep in the bowels of a noisy glaring garage under the airport. I drove and thought I would never get out of the labyrinth. Once on the streets every pedestrian was a carjacker, and I feared for my life. I was completely unarmed and cursed airline restriction on handguns. My friend was relaxed, enjoying the sights, completely unconcerned about our peril. We did survive the drive out into the Iiiinois countryside without incident.

    The drive through the farmlands was glorious: farmhouses with several acre lawns and large farm ponds or streams nearby. Lots of space, children could come home from school, stroll out and catch some fish else pot some ducks in the fall. Plenty of space for pets and farm animals. I was driving throught heaven on earth.

    My colleague on the other hand did not look so delighted. He was nervous and tense as he tried in a distracted way to sustain conversation. It turned out that where I saw a bucolic idyll, he saw Baptists with guns. He might as well have been trapped in Deliverance. He was appalled at my suggestion that we stop in small town and have some hamburgers. He never relaxed until we reached the University.

    • hbd chick says:

      @henry – “I grew up in a small town in northern Appalachia and I second Greg’s thoughts and opinions.”

      i grew up in a large city in the midwest, but spent large parts of the summers during my childhood back in “the old country” on my grandparents’ farm. i still have connections to family back there, and the differences in attitudes and understanding of human nature between (urban) here and there are quite remarkable. almost everybody i know over there understands that there are innate difference between individuals, men and women, different peoples, etc. this clearly has to do with “thick local knowledge,” but also, to echo what dearime said, has to do with farmers having an understanding of breeding.

      urban people are really clueless! (~_^)

  9. Scot says:

    It is maybe incorrect to assume that the advantage is purely mental.Huxley claimed that schizophrenics are more resistant to many diseases (excluding TB if i remember rightly) and especially resistant to allergies and shock.” I read somewhere they have fewer mast cells.

    To meet anyone you have to socialize. Someone with schizoptypal personality disorder (need for social isolation) who probably never is going to develop full schizophrenia won’t do that and is not going to reproduce so that is a lot of schiz genes down the drain right there. In the modern world the fitness of male schizotypals is probably as low if not lower than it has ever been. Females are maybe different I don’t know.

    If someone goes out and can pass for normal and develops schiz later than they reproduced it makes sense what your saying and I know of people like that, he’s an artist by the way (his son got it too) .Grandparents can help raise children and I suppose they always have .

  10. Kev says:

    “lack of class differentiation”
    My father owned a small town car dealership. Parents divorced and we slipped to lower middle class/working poor. Our next door neighbor was a doctor/nurse married couple with three kids. Still friendly (Facebook and reunions) with doctors kids who are now doctors. Good people…

  11. carin says:

    “My colleague on the other hand did not look so delighted. He was nervous and tense as he tried in a distracted way to sustain conversation. It turned out that where I saw a bucolic idyll, he saw Baptists with guns. He might as well have been trapped in Deliverance. ”

    Henry, are you sure your passenger wasn’t Woody Allen?

  12. Protagoras says:

    Henry, running in families was OP’s phrasing. I can’t see the study you recommended because of the paywall, and the abstract makes no indication of what steps were taken to assure the sample included diverse environments. Obviously, the smaller the variation in environments, the smaller the environmentally-produced variation in traits will be, and so the larger the heritable variation will be within that population. To take one obvious example, the Flynn effect, whatever it is, is a huge environmental effect on IQ. Unless the study examined genetic samples of people from decades ago as well as from the present time, though, the study would not detect any of the impact of the Flynn effect, as the Flynn effect tracks variation in environment that are distributed chronologically. Omitting that rather large effect would already guarantee that the study would substantially overstate the importance of heritable factors, and who knows how many other environmental effects they are missing due to an insufficiently diverse sample?

    • Henry Harpending says:

      The samples are all from large longitudinal studies of males (I think) in northern Europe so not much environmental diversity I suppose. Trouble is that no one on earth has any idea what environments cause environmental effects. The Flynn effect is also a mystery: I think of it as an artifact of practice with IQ-test-like problems in schools. It does seem to have stopped and even reversed in Scandinavia in the last few decades. I do remember reading this, can’t cite a source for you.

      The import of the paper I cited (sorry about the paywall!) is that a whole family of criticisms of testing is that there are many sources of family similarity at least potentially. In mammals uterine effects are important for a lot of traits. The SNP studies exclude people who are related in any way, even to second cousins. They then measure kinship among subjects from the genes and find the right correlation with IQ differences. So shared family environment is gone because the subjects are strangers to each other.

      • saintonge235 says:

        Is the Flynn effect environmental? You’d have to control for genetic variation to find out, I’d think.

        I note that during the time period the Flynn effect was strongest, there was substantial increase in personal mobility. It seems quite possible that large scale migrations within the U.S. would break down communities that were mildly inbred, with the resulting hybrid vigor quite possibly enough to account for the IQ rise.

        The bottom line, as I see it, is that almost all who believe in the large effect of environment assume it without evidence, and make no attempt to control for genetic difference. As with the cancer studies where everyone assumed they were using different cell strains, but in fact were all using HeLa cultures, a lot of work needs to be tossed and done over properly.

    • Henry Harpending says:

      Thinking about your comment, I read the data as showing a substantial shrinkage of the BW gap in the United States as a consequence of the Civil Right Act. There were real grounds for optimism about that gap in the 1980s but then the closing stopped. My take would be that having things like textbooks and heated schoolrooms does make a difference in test scores. Since then, to the present, the gap has remained quite stable at about one standard deviation. A good source is the NAEP data from the Feds that can be found on the web by searching for “Nation’s Report Card.” I rely on the grade 8 reports because many kids have dropped out of school by grade 12.

  13. Scot says:

    Concern with mental disorders in the family background of prospective mates in traditional society.
    “A person with a psychiatric disorder was a blot on the marriage prospects of the entire family for generations,with the result that families made every effort to prevent psychiatric disorders from being known to the wider community”

    John Napier “A Plaine Discovery of the Whole Revelation of St. John, which he regarded as his most important work. Napier believed that the end of the world would occur in 1688 or 1700.”.
    He spent a awful lot of his time time on biblical calculations, just like George Price.

  14. Scot says:

    What about antagonistic pleiotropy, disease resistance in infancy, schiz in early adulthood?

  15. Harold says:

    I’d guess having one child versus having many would be similarly influential.

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