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How Many Generations of Imbeciles Is Enough?

August 2nd, 2006 · 9 Comments

American Scientist reports that the Flynn Effect—the steady increase in IQ scores from one generation to the next—has leveled off and is beginning to reverse. (Presumably this bodes ill for the thesis of Steven Johnson’s Everything Bad is Good for You, which leaned heavily on the Flynn Effect to support the argument that video games and more complex TV plots were making us smarter.) James Flynn explains the waning of his eponymous effect this way:

Flynn is convinced that the cause of his eponymous effect has to do with changes in the environment that allow children more opportunity to exercise the kinds of skills probed in today’s intelligence tests–changes like a shift to smaller family sizes, which allow parents more time to interact with each child, for example, or devotion of an ever-greater portion of kids’ leisure time to abstract, mentally demanding games. He points out that in industrialized, middle-class countries (like those of Scandinavia), such influences must be reaching a point of saturation: “You can’t really get the family much smaller than one or two kids.” And the current craze for Sudoku puzzles not withstanding, as Flynn says, “eventually, people do want to relax.”

Is there any way I can point out the other obvious factor in play without being branded a closet eugenicist? Well, here goes anyway: Dumb people have more babies. Or, to be more precise about it, it’s pretty clear that fertility varies inversely with affluence and education: rich college graduates, as a rule, do not have huge families. Obviously, income and education don’t perfectly track native intelligence, but ceteris paribus you’re probably going to find more genes coding for higher intelligence in a group of affluent and highly educated people than a group of poor dropouts. Even a recent New York Times Magazine piece whose central point was how important environment is found that when children born to parents from one group were raised by parents from another, environment made a big difference, but genetic endowment trumped it. (That is to say, kids with “rich genes” growing up in poor households still scored slightly higher on intelligence tests than kids with “poor genes” growing up in rich households.) Of course, as Mark Kleiman points out, some of that difference might have to do, not with genes, but with fetal environment, since the affluent and educated are also more likely to get good nutrition and prenatal care. That suggests you might get a few more decades of Flynn Effect by improving those factors for the poor, but in the long term the upshot is going to be the same if the fertility gap holds.

All this reminds me of a movie I heard about a while back, penned by Mike Judge of Office Space and Beavis and Butthead fame, which now appears to be in production under the title Idiocracy. The premise is that a young, utterly average young private is put into suspended animation by the Pentagon for a thousand years, and discovers upon awaking that he’s become the smartest man alive. Anyway, some commenter who knows more about genetics and demography than I do should explain why this will not, in fact, happen.

Tags: Science



9 responses so far ↓

  • 1 Jadagul // Aug 2, 2006 at 9:48 pm

    I don’t have anything particularly insightful to add at the moment, but you might want to fix the hyperlink around “Idiocracy”—you left out a “>” and thus your hyperlink swallowed a whole couple sentences; I had to pull up a source code chart to read it.

  • 2 Tim Lambert // Aug 2, 2006 at 11:00 pm

    It won’t happen because in a few years parents will be able to select the genes for higher intelligence in their children. Plus it probably won’t matter any more than genes for poor eyesight matter now that it can be corrected by glasses or surgery.

  • 3 Karen // Aug 3, 2006 at 1:46 pm

    So how did the “poor gene” kids raised in the rich families compare to poor gene kids raised in poor families? Was there any improvement in the better environment, and I have to say I’d be stunned if there weren’t.

    I think we can avoid your World of Stupid People by improving the lot of the disadvantaged over here. By improving, I mean in addition to vaccinations, braces, and sufficient food, also intangible things like reducing the acceptability of violence as a means to solve problems and encouraging them to delay gratification and such. (My husband is a lawyer for the prison system. You have no idea how many people thing that beating some guy half to death in a bar fight was a completely rational response to an insult. Sadly, the beatee all too often agrees with his assailant. Also, I have no prescriptions for how to do this at all. Please let’s agree that it’s a noble goal but leave the details for later.) Anyway, after I waive my magic wand and establish the reign of good taste and good manners in all the nation’s trailer parks and housing projects, I expect that the least-wretched will have much improved IQ’s, and consequently start acting like typical smart people. It won’t elimate dimwittedness, but it will at least reduce the environmentally-induced stupidity. Then, there will be much fewer stupid people to reproduce, and we can start working on something like eyeglasses or the PKU diet or some other treatment for the genetically slow.

  • 4 Julian Sanchez // Aug 3, 2006 at 2:13 pm

    Yep, there was definitely a significannt improvement. The short version is that when environment is held constant, “rich gene” kids have about 16 IQ points on “poor gene” kids, but the shift from poor to rich environment is worth about 12 IQ points to each of them. (These are, obviously, averages.)

  • 5 Karen // Aug 3, 2006 at 4:37 pm

    If I understand you correctly, then if all kids had a rich environment, would there be a gap of four IQ points between the groups, or does the 16 point gene advantage hold steady if everyone has the good environment?

    Sorry if I’m missing something really obvious; it’s late in the day and I had a hearing this morning, and after the caffeine and the adrenaline wear off, my brain pretty much gives up.

  • 6 Julian Sanchez // Aug 3, 2006 at 5:21 pm

    No, the “rich gene” kids have a 16-point average lead whenever the environments are constant, including when everyone has a rich environment.

  • 7 James // Aug 7, 2006 at 2:53 pm

    Ah, the “Marching Morons” hypothesis.

    Problem number 1 is the notion that IQ tests measure a single, underlying attribute. I wrote a brief piece on this fallacy recently, which can be found here:


    More generally, IQ tests have a scoring system that basically matches the mental pattern of an urban, college-educated, middle class individual, so the closer the test taker comes to matching that pattern, the higher (in general) the score will be. The Flynn Effect, in part at least, is probably result of urbanization and the channeling of larger and larger numbers of people into the college system. Johnson’s thesis that television is a major cause might have some merit, but more as a homogenizing influence, I suspect.

    There are any number of reasons why the “dumb people have more kids” scenario isn’t valid. Those include regression to the mean, the fact that IQ isn’t even close to being a close genotype/phenotype match, and the key word isn’t “dumb” but “uneducated.” It applies primarily to women, i.e. uneducated women do tend have more children, largely because education is correlated with access to birth control. This is not a chain of correlation to serve as a basis for policy.

    All that the numerous “heritability” studies calculate is the relative variance associated with “heredity” and “environment” given a pre-existing set of both. In other words, what is being measured is environmental variability of a given situation (plus, on occassion, the willingness of a researcher to commit something akin to fraud). I can, for example, enormously decrease any given person’s IQ score with the judicious application of a ball peen hammer, but this proves nothing about the efficacy of universal education, does it?

    By and large, the heritability of IQ debate has public education as its focus, and inherited privilege as a subtext. People’s willingness to believe the grand conceptual model that is being sold by very poorly constructed models of intelligence depends very much on what their pre-existing views are on those points. So anyone wishing to seriously consider the matter should first be clear on their opinions on those topics, and then try to make allowances for the inevitable biases that will occur.

  • 8 Gryph // Aug 11, 2006 at 4:14 pm

    I’ve been thinking, lately, that these fertility trends may wind up being nonmonotonic. The wealthy currently have fewer children largely because they choose to invest very heavily in each child. For these people, children are a luxury good. On the other hand, for the poor, children might be regarded as a resource: of household labor or security in old age.

    If this is right, then fertility rates will decline as the poor become more affluent. But what happens when the rich become even richer? It seems possible to me that they might have additional children because they can easily afford to raise them.

    I don’t know whether the very rich currently have slightly higher fertility rates than the merely well-off, but it seems possible to me that they do. If so, it might make sense to expect fertility to rise in the next several decades in the developed world. I know my parents would have had at least one more child if they had been effectively free.

  • 9 Steve Sailer // Aug 21, 2006 at 4:39 am

    My impression is that very rich men have an above average number of children. I’ve looked casually at biographies of Fortune 500 CEOs and PGA Tour golf pros, and both have a lot of kids, often with two or more wives.

    I don’t know, however, whether this class is large enough to make much of a difference.