Conceptual starter kit for thinking about genes, race, and IQ test scores II

For the purposes of looking at the second question (from the first post), “Does this make you think that differences among IQ scores between races are genetic?,” let’s accept that the answer to the first question, “What does it mean to say IQ test scores are largely genetic?” is that something called heritability is high for IQ test scores.

In the USA we see persistent large differences in average IQ test score exist between racial groups.

Why?  (asking for audience input)

But no environmental factor, or composite of factors, seems to be associated strongly with the group average differences (Flynn 2007; but see Fryer and Levitt 2004).

This has led some researchers to make a two-part argument: the high heritability of IQ test scores within racial groups coupled with a failure of environmental hypotheses to account for the group differences supports—or lends plausibility to—explanations of mean differences in terms of genetic factors (even if these factors have yet to be elucidated) (e.g., Jensen in Miele 2002, 111ff).

Does this seem plausible to you? (waiting for audience input)

Consider this additional information.

Flynn ( 1994) has pointed to large gains in average IQ test score between generations in developed countries (now called the Flynn effect).

No environmental factor, or composite of factors, such as diet or years of education, has been shown to be associated strongly with the generational differences.

Now bring in the two-part argument: the high heritability of IQ test scores within groups coupled with a failure of environmental hypotheses to account for the group differences supports—or lends plausibility to—explanations of mean differences in terms of genetic factors.

If we look at each generation as a distinct group, the two-part argument means we should favor explanations of generational differences in terms of genetic factors, yet the change in gene frequencies in a human population over one generation is negligible.

Conclusion?  The logic of the two-part argument must be flawed and must be put aside.

That leaves us still having to explain large differences between generations—or racial groups—in a highly heritable trait.  That ” IQ paradox” is a discussion for another time.

References

Flynn, J.R.: 1994, IQ Gains over Time, in R. J. Sternberg (ed.), Encyclopedia of Human Intelligence, Macmillan, New York, pp. 617-623.

Flynn, J.R.: 2007, What is Intelligence? : Beyond the Flynn Effect. Cambridge University Press, Cambridge.

Fryer, R. and Levitt, S.: 2004, Understanding the Black-White Test Score Gap in the First Two Years of School. The Review of Economics and Statistics, 86(2), 447-464.

Miele, F.: 2002, Intelligence, Race, and Genetics: Conversations with Arthur Jensen, Westview Press, Boulder, CO.

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3 thoughts on “Conceptual starter kit for thinking about genes, race, and IQ test scores II

  1. makeitplainonline

    The problem is with the measurement of IQ. We, as a society, have not come up with a strong measure for IQ that eliminates bias between groups. IQ tests are based on one culture’s formulation of intelligence.

    In addition, the tests employed today rely too much on previously learned material. These problems result in the limititaions you are discussing.

    Reply
  2. Chuck

    makeitplainonline says: The problem is with the measurement of IQ. We, as a society, have not come up with a strong measure for IQ that eliminates bias between groups. IQ tests are based on one culture’s formulation of intelligence.In addition, the tests employed today rely too much on previously learned material. These problems result in the limititaions you are discussing.”

    30 years a research have shown that intelligence tests are not biased. (As for what they test, refer here: McGrew, 2009. CHC Theory and the human cognitive abilities project: Standing on the shoulders of the giants of psychometric intelligence research.) That’s not the problem. The problem is that there are real, meaningful average group differences. The issue is the cause. Look at it this way, it would be much easier to say all SAT, GRE, MCAT, etc. (and other IQ correlates) were biased and only had high validity for Eurasians, if they were, than to invest trillions into trying to close the gap.

    Whether or not psychometric tests “are based on one culture’s formulation of intelligence” is irrelevant for two reasons: 1) “Intelligence is a European term — the roots ‘inter’ ‘legere’ literally mean to read, understand, and pick between — which refers to a rational based way of thinking about the world which matches what academic tests measure; If you think some peoples are less capable of that and want to come up with another term for how they think about the world, do that. 2) that quality measured by the said tests, whatever you want to call it, is important in contemporary society — it’s the best predictor of job performance.

    Pete’s point here is to separate what we now know about population differences form behavioral genetics and from individual differences — to prevent people from making fallacious inferences. He want to keep people from reasoning in the opposite manner of how you appear to be:

    A. Important differences between populations CAN NOT be genetic, so:
    1. There CAN NOT be average unbiased differences in psychometric intelligence, or
    2. Psychometric intelligence tests CAN NOT be valid and predictive general intelligence, or
    3. There CAN NOT be large scale population differences.

    His point is to show (correctly) that 1-3 does not imply A.

    This brings me to my point:

    Pete,

    Let me ask, do you think it’s ‘natural’ for people to infer a genetic etiology for the racial gap, when they hear about 1-3.

    My impression was that Left-Liberals, for a number of overlapping reasons, argued A and 1-3 in the same breathe. So now that 1-3 seem to be true, many people are prone to conclude that A is true.

    I don’t know.

    Reply
  3. Chuck

    Ok, I just wanted to finish up what I was saying…

    I guess I wonder why you would give the above talks to high schoolers. It seems we will know the magnitude of any differences within 5-10 years, courtesy of behavioral genetics. To the extent there are average differences, there are average differences and this will be known. To the extent there aren’t this will also be known In the meantime, we have numerous people like makeitplainonline or you typical Nytimes opt ed writer, who will reinforce the idea that there aren’t, which is probably the safe bet, relative to how many people look at things.

    Maybe you would say that these talks are necessary to forestall popular misconceptions which spontaneously arise– after all, since some prominent researchers apparently hold them — in spite of the evidence — people must be hardwired to think this way. If the later consideration has anything to do with the impetus for the talks, I would suggest you consider that some prominent researchers consider the various hereditarian hypotheses plausible because they actually are. To put it another way, when they cease to be plausible (or possible) they will not be considered (at least by informed people).

    In regards to plausibility you make two points:

    1) The most common argument made by researchers for thinking that differences among IQ scores between races might be genetic is flawed
    and
    2) The various hereditarian hypotheses are implausible.

    First, 2 doesn’t follow from 1. The various hereditarian hypotheses are plausible as long as a) we know that there are group performance difference and b) there could be differences due to genetics. The whole point of the last 30 years of disinformation was to deny b). It was to say: populations are genetically the same (Lewontin), the said differences can’t possible be (partially) genetic, and there couldn’t possibly be a reason for the difference to come about (Gould, Diamond, various) — and by virtue of that, to say: a hereditarian hypothesis was implausible and impossible, evil, and irrational. Well — we know all those are false. So it stands that the various hereditarian hypotheses are plausible. In fact, we know of average genetic differences that seem to differentially affect populations’ behavior — cultural neuroscience comes to mind and specifically the research on dopaminergic alleles. (e.g. the “liberal gene,” which is virtually absent form N. East Asian populations — they (on average) seem to have the Confucian gene, the short allele)

    Second, 1 is complex. Flynn argues that the common argument is flawed — and he does so by offering a rather complex hypothesis concerning the Flynn effect. If we are dealing with plausibility (“for thinking”), we would have to consider the plausibility of Flynn’s hypothesis (1). For my own part — I would say the possibility of his hypothesis weakens Jensen’s trap, but it doesn’t totally undermine it.

    (1).

    Jensen’s argument was: J1) a difference found between populations A and B (dp) is either due to a) genetics, b) environmental factors (vE) which also account for variance within A and B, or c) unique environmental X -factors that just work between the populations and do not show up on heritability estimates; J2) high heritability effectively rules out b); J3) in an otherwise shared environment c) seems, on the face of it, implausible; J4) in absence of a plausible c) posit a) as the default explanation.

    Flynn’s counter argument is: F1) a difference found between populations A (time 1) and A (time 2) (dt) is either due to a) genetics, b) environmental factors (vE) which also account for variance within A(t1) and A(t2), or c) unique environmental X -factors that just work across time and don‘t show up on heritability estimates; F2) if the differences between that population at time 1 and time 2 is rapid, it effectively rules out a), leaving b) or c); F3) c) is “fantastic”; F4) there was such a difference (Flynn effect) therefore, F5_ the difference must be due to b) which means there is something wrong with J2).

    Flynn concludes that Heritability don’t constrict vE explanations and there must be some G-vE factors, which are undetected by heritability estimates. In short, g-vE X factors!

    On g-vE X-factors (Flynn 2001):
    “Thanks to industrialization, it is likely that the cognitive complexity of the average person’s job has increased over the last century. There is no doubt that more-demanding educational credentials control access to a wide range of jobs. There are far more people in scientific, managerial, and technical positions than ever before.6 Increased leisure time is another possible trigger for IQ
    gains, as some activities undertaken during extended“

    “Between generations, the mask slips. For it to do its work, the
    worse environment of the earlier generation would have to be
    matched by worse genes for IQ; and the better environment of the
    later generation would have to be matched by better genes for IQ.
    However, because the two generations are equivalent for genes,
    there is no matching and therefore no masking. The potency of
    environmental factors stands out in bold relief.”

    Since we are dealing with plausibility, Jensen’s argument is only undermined if:

    1) it’s more plausible that the testing differences over time (dt) represents real differences in capacity — a real increase in g– than that they represent measurement artifacts (since IQ tests measure relative differences not absolute differences). If not, than differences between a time cannot be compared with differences between populations at a time.

    2) If, given 1), genetic explanations for the Flynn effect are less plausible than mysterious g-vE factors.
    See: Mingroni, 2007. Resolving the IQ Paradox: Heterosis as a Cause of the Flynn Effect and
    Other Trends

    3) If, given 1-2), X factors are not plausible explanations for the Flynn effect. (One reason X factors are especially implausible (J3) for the B-W gap is that they need to differentially hit one population living in the same (apparent) environment as the other. — But when it comes to the W(t1)-W(t2) gap, the two populations are living in a different environment, times literally having changed.

    4) If, given 1-3), it’s plausible to assume that whatever is causing the Flynn effect can work in a similar manner within the said populations. (The B-W gap is not connected to the Flynn effect, so these have to be different anyways); refer back to 1)

    And,

    5) If, given 1-4) it’s just as plausible that Flynn’s mysterious g-eV X-factors can differentially hit one population living in the same (apparent) environment as one (genetic) population living at two different times.

    Flynn says yes to 1-4. And explains 5 by positing (minor) average genetic difference between populations!

    “The standard model that poses the paradox assumes that environment
    and genetic endowment are uncorrelated. Applied to
    basketball, this implies that good coaching, practicing, preoccupation
    with basketball, and all other environmental factors that influence
    performance must be unrelated to whether genes contribute
    to someone being tall, slim, and well coordinated. For this to
    be true, players must be selected at random for the varsity basketball
    team and get the benefits of professional coaching and intense
    practice, without regard to build, quickness, and degree of interest”

    (G-E explanations are passive, reactive, or active. The first two can be detected, leaving genetic predilections for seeking superior environments — I guess like the Confucian gene)

    Reply

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