Unz on the genetics of IQ

Comments on my research often approach the edge of debates about race and IQ, so despite my general lack of interest in going there, I keep a rough watch on what is happening in the area. A couple of weeks ago, Ron Unz made a solid entry into the debate by ploughing through a mountain of data on race, income and IQ to come to the following conclusion:

The central thesis of Lynn and Vanhanen’s work might be called the “Strong IQ Hypothesis,” namely that IQ accurately reflects intelligence, that IQ is overwhelmingly determined by genetics, and that IQ is subject to little or no significant cultural or economic influence after we adjust for the universal Flynn Effect. …

Yet an objective review of the Lynn/Vanhanen data almost completely discredits the Lynn/Vanhanen “Strong IQ Hypothesis.” If so many genetically-indistinguishable European populations—of roughly similar cultural and historical background and without severe nutritional difficulties—can display such huge variances in tested IQ across different decades and locations, we should be extremely cautious about assuming that other ethnic IQ differences are innate rather than environmental, especially since these may involve populations separated by far wider cultural or nutritional gaps.

We cannot rule out the possibility that different European peoples might have relatively small differences in innate intelligence or IQ—after all, these populations often differ in height and numerous other phenotypic traits. But this residual genetic element would explain merely a small fraction of the huge 10–15 point IQ disparities discussed above. Such a view might be characterized as the “Weak IQ Hypothesis”: huge IQ differences between large populations may be overwhelmingly due to cultural or socio-economic factors, but a residual component might indeed be genetic in origin.

Regardless of the merits of Unz’s argument – among other things, he ignores the potential for measurement error, and while he notes persistently high east Asian IQ, he does not ask how this fits with his picture – the weak IQ hypothesis does not necessarily rule out IQ as a major cause of cross-country income differences. If slightly higher IQ has a positive effect on economic growth, this may in turn then allow IQ improvements through improved nutrition, which would then allow for further economic growth. A virtuous cycle would begin. Small changes in initial conditions can have a substantial effect on final outcomes. We can of course come to a similar argument with no genetic basis to IQ if there was a shock that temporarily lifted income to allow the IQ increase and trigger the growth-IQ feedback loop.

Unz’s approach raises one other interesting question, which Unz himself asks:

We are now faced with a mystery arguably greater than that of IQ itself. Given the powerful ammunition that Lynn and Vanhanen have provided to those opposing their own “Strong IQ Hypothesis,” we must wonder why this has never attracted the attention of either of the warring camps in the endless, bitter IQ dispute, despite their alleged familiarity with the work of these two prominent scholars. In effect, I would suggest that the heralded 300-page work by Lynn and Vanhanen constituted a game-ending own-goal against their IQ-determinist side, but that neither of the competing ideological teams ever noticed.

Presumably, human psychology is the underlying explanation for this mysterious and even amusing silence. Given that Lynn and Vanhanen rank as titans of the racial-difference camp, perhaps their ideological opponents, who often come from less quantitative backgrounds, are reluctant even to open the pages of their books, fearful lest the vast quantity of data within prove that the racialist analysis is factually correct after all. Meanwhile, the pro-racialist elements may simply skim over the hundreds of pages of dry and detailed quantitative evidence and skip to the summary text, which claims that the data demonstrate IQ is genetically fixed and determines which nations will be rich and which will be poor.

The whole piece by Unz is worth the read, as is Richard Lynn’s response.

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