There’s the old joke about the guy looking for his keys under the lamplight because, even though that’s not where he lost his keys, the light’s better there. I feel that way about studies of I.Q.. When critics, like Howard Gardner, object that such measurements fail to capture important aspects of thought, psychometricians reply that concepts like Gardner’s “multiple intelligences” don’t produce the same kind of “stable” test results they get from I.Q. tests, so they need to keep using I.Q.! It strikes me that what we have here is a concept that has been perpetuated in order to legitimate the continued existence of a discipline, and of a testing regime, rather than because it tells us anything important about the mental abilities of those tested.

I’ve been looking at this issue because four of the top political bloggers (Atrios, De Long, Kevin Drum, and Matt Yglesias) have ganged up on Andrew Sullivan for his recent endorsement of the central tenants of The Bell Curve. As a result of all these posts we get a great list of online articles debunking the book, to which I’ve added a few more and grouped them all here for your reference. The critiques vary in whether or not they accept the notion of I.Q.. Some accept it, but claim it isn’t genetic, others accept a genetic component, but deny that this correlates with race, while others (like Howard Gardner and Stephen Jay Gould) are more critical of the very notions of intelligence that are supposedly being measured in the first place.

  • Thomas Sowell’s American Spectator article, in which he discusses the “the work of James R. Flynn, who found substantial increases in mental test performances from one generation to the next in a number of countries around the world.” Findings which disprove any link between genetics and I.Q. (originally linked in this DeLong post, and metioned in Matt’s post as well.)
  • Nicholas Lemann’s debunking in Slate: “What Herrnstein and Murray used to measure IQ is actually a measure of education as well as intelligence.” (also from Matt.)
  • Intelligence: Knowns and Unknowns.” The report by the American Psychological Association which I make fun of above, but which is well worth reading – especially with regard to whether there is any link between intelligence and race. (via Kevin Drum.)
  • Samuel Bowles and Herbert Gintis 2002 paper, “The Inheritance of Inequality” [PDF] which debunks the notion that social inequality is genetic. (via Brad DeLong, who has a summary of the findings.)
  • Howard Gardner’s critique of The Bell Curve in The American Prospect, in which he elaborates on the limitations of I.Q.
  • Two defenses of I.Q.: One by Linda S. Gottfredson in Scientific American, and another by Christopher F. Chabris in Commentary.
  • Responses by Flynn, Gardner, and others to the article by Chabris.
  • Wikipedia pages on The Bell Curve, Race and Intelligence, IQ, the Flynn Effect, Gould’s book, The Mismeasure of Man, and Howard Gardner’s concept of Multiple Intelligences.

9 thoughts on “I.Q.

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  3. This debate is absurd. All the left has to do is show where Blacks have outscored both Asians on IQ tests, and the issue would die.- The black/white issue is only going half way…

    Another problem is that Philip Rushton did catscanned skull measurements, that supposedly show blacks do indeed have a smaller cranium size….how can you argue with this?

    The main issue for the left as they see it is that if the Bell Curve is correct, than the KKK, and the Nazis are legitimate causes,so if its true or NOT, the LEFT is morally obligated to oppose the Bell Curve. The problem is that the Bell Curve is only one book of many, and we have large social issues with hispanics and blacks and white flight in Florida and California, and Africa and Latin America are hardly models of Liberal republics…etc ……..

  4. If IQ isn’t a valuable measure of mental ability, then why is Lynn and Vanhanen’s “national average IQ” estimate such an incredibly robust regressor in the thousands of cross-country growth regressions I run in my work with psychologist Joel Schneider?

    Here’s the wiki version here:


    Blatant plug: Here are links to two papers I’ve authored/coauthored regarding the power of national average IQ to explain a lot of the differences we see in living standards between countries:


    The short version is that even after you control for just about everything in sight, countries with higher average IQ’s grow faster and become richer than lower IQ countries. It just blows away traditional measures of human capital like schooling.

    We can narrow these massive cross-country IQ gaps through better nutrition, as the members of the Copenhagen Consensus concluded, but it’s hard to create good brain-health policies when unscientific, emotionally-driven criticisms of IQ are the norm…..


  5. Garett,

    Lynn and Vanhanen’s work is far from uncontroversial, as the wikipedia link you provide shows. But, assuming that there is some correlation between IQ and wealth, that still doesn’t explain what is being measured in IQ tests.

  6. Garett,

    I read “IQ in the Ramsey Model: A Naïve Calibration”, largely because, criticially in social science, I’d consider that the correct isolation of such an important single factor is difficult when the possibility of misrepresenting an artefact of reverse causality, as you put it, is seems a quite plausible possible alternative explanation (IQ’s intercorrelation with socioeconomic status coming to mind immediately).

    I can’t say I found the East Asia empirical example particularly robust, given that “East Asia” seems to be defined quite nebulously . Certainly Figure 3 relies on studies from countries such as Japan and Hong Kong to give any sort of time depth, when more studies from countries such as Indonesia, etc (where development would appear to have been much more rapid), would appear to do more to rule out the reverse causality interpretation*. Obviously this is an economics paper, though, and treating the empirical evidence in psychology in any great depth is presumably slightly outside its remit, but in any event, this is what is required to show the model works in the way you describe it.

    ‘but it’s hard to create good brain-health policies when unscientific, emotionally-driven criticisms of IQ are the norm…..’

    Hmmm, I’d have considered that, in a free marketplace of ideas, such a valuable tool would have easily overcome such poorly focused criticisms.
    Secondly, is it so difficult to create good brain-health policies? They’d seem quite straightforward to propose from an epidemiological perspective.

    * I had a problem with Plio-Pleistocene hominins that looked like this, oddly.

  7. “Western Sensibilities” are being measured in ‘IQ” tests. COGNITIVE ABILITIES,are CORROLATED to race, crime, standard of living etc… Political Correctness continues to amaze me, among the “college educated elite”.

    The severe left keeps on pounding the drums of feminist,marxist emotional egalitarianism. To what end? Has “liberal” think really done anything, by not holding people to a higher standard? Can a chimpanzee “behave” like a gorrilla?

  8. IQ is only important for predicting academic success; it cannot predict success in life. Sure it might improve chances for a better life pecuinarily. There are plenty of broke “genuises” and plenty of wealthy idiots. IQ is just a measure of how quickyoumight pick up studies but it also says nothing about interactions socially; you can have a 150 IQ and be socially retarted; this puts you at a disadvantage for being a “team player”- so overall if you have a good Iq and a great personality you are better off than lacking in either. I would not put too much promise in all the “gifted” kids who grow up; they are usually banal in their fields- great regurgitators but not much more. Intelligence – genius is what we DO with our lives – if that is selfish or giving is our business. What did you create? What did you make foryourself or society? A number of 124 or 146 given to a 12 year old is nothing. Look at their lives when they are 60 and see what they have done for society and/ or themselves. PEACE – JDA

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