»  National Review Online

September 24, 2007

  Magical Thinking on IQ


I can never think about the topic of IQ without recalling the late Willard Espy's immortal "I-ku haiku." From memory:

I ku; you ku; he, she, or it ku;
We ku; you ku; they ku.
Than ku.

Espy's lines don't make much sense, but they make more sense than a lot of the stuff that gets written about IQ. Case in point: David Brooks's remarkably lame-brained piece in the New York Times the other day. I say "remarkably" because David is a very smart guy, and people that smart do not often sign their names to such unmitigated twaddle.

The wittiest comments on David's piece came from the Anglosphere's best living human-sciences journalist, Steve Sailer. Steve supplies the full text of the Brooks piece for good measure (with his own comments at the end). Alex at the Gene Expression website conducted a point-by-point demolition of the Brooks piece, with linked bibliographical references—I counted 23. No doubt there have been other critiques around the web from people WHO ACTUALLY KNOW SOMETHING ABOUT PSYCHOMETRICS.

The Brooks piece caught my attention because I had just finished reading Michael Hart's book Understanding Human History. Hart's aim is to do for the history of our species what Lynn and Vanhanen did for economics: to bring forward intelligence—the different statistical profiles of different peoples on measures of cognitive function—as an important factor. Not the only factor, of course, but an important factor.

History on the grand scale is about different human populations interacting via war, trade, migration, or religious proselytizing. The Proto-Indo-Europeans occupied Europe; Phoenician traders established Carthage; Dravidian-speakers swept in over the aborigines of India, and were swept over in turn by Indo-European speakers; the Roman Empire fell to German pagans, the Meso-American ones to Spanish Christians; Polynesians colonized the Pacific; black African slaves were shipped to Arabia and the Americas, while white European ones were shipped to North Africa; Jews from the Middle East scattered into Europe to form merchant communities; the Mongol Horde came and went; Buddhism spread throughout southeast Asia; the East India Company morphed into British India, and so on.

Different populations, descended from different small founder groups, and evolved through hundreds of generations in different homelands under different selection pressures, emerged from those homelands at the end of the Neolithic and began these historic exchanges—began to trade, fight, conquer, enslave, settle, convert. If it is the case that intelligence—the ability to comprehend and manipulate the world, including the social world (which includes the military and political worlds)—if it is the case that intelligence is differently distributed in different populations, that fact must have had great consequences for history. And if not, then obviously, not.

On the premise that it is the case, Hart works his way through history taking intelligence as one of the determinants for events. He tells the story of the earliest human migrations, paralleling the account in Nicholas Wade's fine book. He comes up with novel explanations for some puzzling facts—e.g. that successful north-to-south invasions are much more common than south-to-norths. He gives a good critique of Jared Diamond's thesis that, to put it in the smallest possible nutshell, natural selection came to a screeching halt 50,000 years ago—that the laws of biology were suspended back in the paleolithic in order that 21st-century Western liberals should not be plagued by thoughts that are unpleasant (Diamond's actual adjective is "loathsome") or unpopular.

Hart is not obsessive or dogmatic about the IQ factor in history, and freely admits that population differences in intelligence may have played no part, or an unknowable part, in some big events.

In a discussion of possible causes for the fall of the Roman Empire, for example, he includes, as possible cause number 8, that the decline of Rome may have been due in part to "the deterioration of the Roman gene pool, caused by interbreeding with conquered peoples and slaves who, on average, possessed lower native intelligence than the Romans." His final conclusion, though, is a balanced and agnostic one:

Conclusion: The cause of the drastic decline and eventual collapse of Rome is still an undecided question. The most likely explanation is probably some combination of the social-decay hypotheses described above. However, the possibility that climate change played a major role—perhaps even the central role—cannot be ruled out.

(Just for the record, Hart's other possibles are:

           1. Loss of faith in the traditional national religion.
           2. Loss of nationalist/patriotic feelings.
           3. Increased corruption.
           4. Impoverishment of the peasantry.
           5. Lack of plunder.
           6. Foreign attacks.
           7. Depopulation due to major epidemics.
           9. Lead poisoning.
           10. Climate change in Western Europe.)

Hart's science is sound so far as I can judge. (He has a bachelor's in math, a Ph.D. in astronomy, and two master's—in physics and computer science.) It's in the nature of the topic that much of what he writes is speculative, but there's nothing wrong with that. Speculation based on sound science is interesting. When science has told us that X, Y, and Z are the case, an inquisitive commentator can say: "Well, then, X, Y, and Z being so, it may be that when we have inquired more deeply and gathered more data, A, B, and C will follow, since they do not contradict X, Y, and Z. Or possibly not; perhaps P, Q, and R—which likewise do not contradict the known facts—will turn out to be the case." This is all a normal part of the imaginative and intellectual to-ing and fro-ing that inspires new research programs, from which in turn new knowledge emerges.

As interesting as all this population-genetics stuff is to us science geeks, what is just as interesting, though in a different way, is the tremendous resistance to it all on the part of non-science intellectuals like David Brooks.

IQ score either does, or does not, measure some real aspect of the human personality. Human populations who underwent the latest stages of their evolution in higher latitudes either do, or do not, have IQ distributions with higher means than those of lower-latitude groups. A people's IQ profile either is, or is not, a determinant of its economic or military success, or cultural prominence. Let's gather the data and crunch the numbers and see if we can get clear answers, shall we? (With the understanding, as always in the sciences, and most especially in the human sciences, that clear answers may not be forthcoming from the datasets we have been able to gather.)

No, say the Brookses, let's not. There was that book a dozen or so years ago, the one that created such a fuss in the political-literary magazines that I and all my friends read. Well, that's quite enough of that. Didn't those guys turn out to be some kind of racists? Euiw! Let's not think about it any more.

And so on... ending up with the highly peculiar spectacle of thoughtful, well-educated conservatives clinging fearfully to the skirts of the late Stephen Jay Gould and the extant Richard Lewontin—both declared Marxists! Anything, any place, any refuge, any companions, anything in the world but be forced to face unwelcome truths—be forced to abandon the warm comfort of wishful thinking and the smiling approval of our social peers.

Knowing that I lean to the nature side of most nature-nurture controversies, readers occasionally email in with something from the newspapers offering evidence for nurturism. My stock response is: "All nurturist claims in the general press must be read with the understanding that there is terrific psychic & social pressure on any commentator or researcher who wants to keep his job and his friends to make as much as possible of any nurturist evidence, and as little as possible of any naturist evidence. You should apply an appropriate bias-correcting discount to all you read."

The ordinary modes of human thinking are magical, religious, and social. We want our wishes to come true; we want the universe to care about us; we want the esteem of our peers. For most people, wanting to know the truth about the world is way, way down the list. Scientific objectivity is a freakish, unnatural, and unpopular mode of thought, restricted to small cliques whom the generality of citizens regard with dislike and mistrust. There is probably a sizable segment in any population that believes scientists should be rounded up and killed.

When the magical (I wish this to be so: therefore it is so!) and the religious (we are all one! brotherhood of man!) and the social (this is what all good citizens believe!) come together, the mighty psychic forces unleashed can unhinge even the best minds. David Brooks's embarrassing little venture into psychometry is only the latest illustration of this melancholy truth.