“a bias toward knowing what I’m talking about”

That’s Ta-Nehisi Coates’ credo as stated in the post disembowling Andrew Sullivan that John linked to below.

In that piece, Ta-Nehisi writes of his having mostly avoided the race-intelligence pit o’ fail, because he does not to his own satisfaction know enough about the technical arguments there.  As John says, that doesn’t prevent Ta-Nehisi from accurately diagnosing the moral bankruptcy of Sullivan’s thinking.

But his framing of the post did drive me back to one of the best web sources of insight on issues of method and meaning in statistical reasoning, the invaluable Cosma Shalizi, proprietor of the Three Toed Sloth blog.  Given that Ta-Nehisi provided an implicit shout out for such sources, I thought I’d dig back into Cosma’s work to provide some context.

Back in 2007, when William Saletan decided to trumpet the “work” of notorious race/IQ “scientist” J. Philippe Rushton, in seeming ignorance of Rushton’s long and well documented record as an associate and aider-and-abetter of overtly racist segregationists,* Cosma wrote a series of long and very carefully reasoned posts explaining what’s goes terribly wrong with most writing about IQ and anything — not just race.  For an overview of the problems with concept of “g” — a general intelligence trait — see this honking elephant of a post.  I can recommend two much shorter and nicely wicked dialogues on the question of intelligence and plasticity — or, really, on the ease with which really bad thinking slips into such questions.

The point of all this, worked through in some detail in the third of his four posts on the subject, is that studies of intelligence that assert “truths” about connections between some conception of the heritability of IQ and race do so from a position of what may most kindly be assumed to be simple incompetence — though in some cases a presumption of malice seems justified.

As Cosma himself warned his readers, any honest confrontation with the methodological hell that is IQ research leads one into a quagmire.  I think I’ve pointed you towards close to 20,000 words (and figures) of his attempt to navigate the mire.  So, if you want to skip the some thousands of words towards which I’ve pointed you, here are his conclusions in nice, compact form:

  1. The most common formulae used to estimate heritability are wrong, either for trivial mathematical reasons (such as the upward bias in the difference between monozygotic and dizygotic twins’ correlations), or for substantive ones (the covariance of monozygotic twins raised apart neglects shared environments other than the family, such as maternal and community effects).
  2. The best estimate I can find puts the narrow heritability of IQ at around 0.34 and the broad heritability at 0.48.
  3. Even this estimate neglected heteroskedasticity, gene-environment interactions, gene-environment covariance, the existence of shared environment beyond the family, and the possibility that the samples being used are not representative of the broader population.
  4. Now that people are finally beginning to model gene-environment interactions, even in very crude ways, they find it matters a lot. Recall that Turkheimer et al. found a heritability which rose monotonically with socioeconomic status, starting around zero at low status and going up to around 0.8 at high status. Even this is probably an over-estimate, since it neglected maternal effects and other shared non-familial environment, correlations between variance components, etc. Under such circumstances, talking about “the” heritability of IQ is nonsense. Actual geneticists have been saying as much since Dobzhansky at least.
  5. Applying the usual heritability estimators to traits which are shaped at least in part by cultural transmission, a.k.a. traditions, is very apt to confuse tradition with genetics. The usual twin studies do not solve this problem. Studies which could don’t seem to have been done.
  6. Heritability is completely irrelevant to malleability or plasticity; every possible combination of high and low heritability, and high and low malleability, is not only logically possible but also observed.
  7. Randomized experiments, natural experiments and the Flynn Effect all show what competent regressions also suggest, namely that IQ is, indeed, responsive to purely environmental interventions.

In other words:  Sullivan is not just wrong; he is not only trafficking in just the all-dressed-up-for-the-21st-century version of the slave-holder’s self justification — as Ta-Nehisi so clearly demonstrated; he is not playing the honest broker, merely seeking research to settle vexing questions; he is writing in what can at this point only be chosen ignorance of what those with actual understanding of the methods and pitfalls of social science have been trying to tell him for lo-these-many years.

I know that I sometimes praise Sullivan for his moral acuities:  his strong stand against torture, his long advocacy of civil equality in the GBLT arena, his belated and partial recognition of the flaws of the Republican party.  But when you stack up his role in creating myths about health care in the Clinton years, and his championing of this kind of stuff, I don’t see how you can count his career as a net positive for the society.

*My only Rushton story:  I was in the room at a mid-’80s AAAS meeting when Rushton was just breaking on the scene with his attention grabbing assertion that intelligence was inversely correlated with penis size, which was in turn specifically correlated with particular races.  It was a day that made me proud to be a science writer, as the great SF Chronicle¹ science editor David Perlman got up in that session and just roasted Rushton.  None of this, “some say, others disagree” transcription-monkey reporting.  Just a thing of beauty and a great lesson in the need to build and pay attention to one’s bullship filter.  That is, of course, exactly what Saletan failed to do.

¹Yes. That paper, which, like lots of Bay Area folk, we regularly referred to as the SF Comical, did/does have some truly first class writers and   reporters, among whom Perlman is one of the best.

Image: Adriaen Pietersz.van de Venne, Fools Have the Most Fun, 1661

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10 Comments on ““a bias toward knowing what I’m talking about””

  1. [...] a bias toward knowing what I’m talking about.” (For someone who actually does know, see here).But Coates’ also taps into an aspect — can we call it a character flaw? — of [...]

  2. Ringleader Says:

    You do your readers a great disservice by not referencing Megan McArdle’s enormously well-informed dissection of one of Cosma’s posts on IQ –


    As with Elizabeth Warren, if the polymath McArdle judges Cosma to be wrong then he is indisputably wrong.

    • Kiwiguy Says:

      As Steve Hsu and Razib Khan have pointed out, anyone who understands factor analysis realises that you can have correlations and a single largest factor even if there are no underlying causal reasons (i.e., it is just an accident). Nonetheless, these models may still be useful.

      Prior to the availability of molecular studies the heritability of type II diabetes was estimated at 0.25 using all those methods. Now molecular studies have identified at least 9 loci involved in the disease. There are other examples in relation to height. So you can’t say that heritability studies, with all their seemingly ridiculous assumptions, are worthless.

      In fact, reading Shalizi closely, you’ll see that he doesn’t think they are either. For instance, he says:

      ***If you put a gun to my head and asked me to guess [whether there are genetic variants that contribute to IQ], and I couldn’t tell what answer you wanted to hear, I’d say that my suspicion is that there are, mostly on the strength of analogy to other areas of biology where we know much more. ***

      Also, in his article on g he seems to accept in the footnotes that intelligence or cognitive ability, as operationally defined by psychologists, is important for economic development.

      ***Cowen points out behaviors which call for intelligence, in the ordinary meaning of the word, and that these intelligent people would score badly on IQ tests. A reasonable counter-argument would be something like: “It’s true that ‘intelligence’, in the ordinary sense, is a very broad and imprecise concept, and it’s not surprising the tests don’t capture it perfectly. But the aspects of ‘intelligence’ they do capture are ones which are vastly more important for economic development than the ones displayed by Cowen’s friends in San Agustin Oapan, however amiable or even admirable those traits might be in their own right.” This would be a position about which one could have a rational argument. (Indeed, I might even agree with that statement , as far as it goes, as might A. R. Luria.) ***

      Even not knowing why these tests work, just analysis of the results shows the tests predict performance and are stable.

      • Kiwiguy Says:

        There is also a paper which actually identifies Shalizi’s criticism

        “In a recent paper,Johnson,Bouchard,Krueger,McGue,andGottesman (2004)addressedalong-standingdebateinpsychology by demonstrating that the g factors derived from three test batteries administered to a single group of individuals were completely correlated. This finding provided evidence for the existence of a unitary higher-level general intelligence construct whose measurement is not dependent on the specific abilities assessed. In the current study we constructively replicated this finding utilizing five test batteries. The replication is important because there were substantial differences in both the sample and the batteries administered from those in the original study. The current sample consisted of 500 Dutch seamen of very similar age and somewhat truncated range of ability. The batteries they completed included many tests of perceptual ability and dexterity, and few verbally oriented tests. With the exception of the g correlations involving the Cattell Culture Fair Test, which consists of just four matrix reasoning tasks of very similar methodology, all of the g correlations were at least .95. The lowest g correlation was .77. We discuss the implications of this finding.”

        Unique batteries of tests given to the same population measure the same “g.” Factor analysis would not produce this identicality.


  3. jre Says:

    … if the polymath McArdle judges Cosma to be wrong then he is indisputably wrong.

    Hee, hee! I read this a couple of times, sniffing for irony. Nope; in the Bizarro-world inhabited by this commenter, Megan McArdle is actually considered to be in the same intellectual weight class as Cosma Shalizi. No — even worse, she is now a “polymath” and Cosma is “indisputably wrong” when the two are in conflict.

    OK; I’m gobsmacked, and almost disinclined to comment, given that the collision of that anti-reality with reality may have already liberated enough energy to vaporize this thread. But, on reflection, I feel compelled to point out that if Megan McArdle were to stand on one end of the plank at the “Test Your Intellect” game, and Cosma Shalizi were to take even a half-hearted swing of the mallet at the other end, McArdle would ricochet back and forth, ringing the Stupid bell with her head, until amoebas drove speedboats.

    Just sayin’.

    • Tom Levenson Says:

      I think your snark meter may need adjustment. Not sure, but the prior comment definitely reads that way to me.

      • jre Says:

        I am delighted to be corrected. It seemed impossible that anyone could take McArdle seriously on this one, but then there was the link to McArdle’s site, and … well, sometimes we are just too doggone eager to see dumb in place of sly. If Ringleader was too subtle for me, my humblest apologies.

  4. Ringleader Says:

    I apologize if my post was misleading…I thought it obvious that McArdle’s take on Cosma’s IQ posts was laughable. I usually think that it’s wisest to ignore a person like McArdle. However, because of her forum at The Atlantic, I see her cumulative effect as pernicious. I’m grateful for Tom’s efforts.

  5. Dam I Am Says:

    Looks like someone’s been cribbing off the Sept ’75 “Letters” section of the National Lampoon – BUSTED on the “until amoebas drove speedboats” steal!

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