To the Editor:
Charles Murray is on safe ground in testing the Cochran-Hardy-Harpending hypothesis of high Jewish IQ by seeking evidence beyond the Ashkenazim in Europe and going back past the Middle Ages to antiquity. In a review of nearly 100 studies of South Asian/North African IQ, Richard Lynn has shown that although IQ scores of Sephardi Jews are lower on average than those of Ashkenazim, they are higher than those of the populations that surrounded them historically. Clearly we are dealing with something deeply rooted in the Jewish past.
J. Philippe Rushton
University of Western Ontario
Charles Murray writes:
Richard Lynn’s review of studies of Sephardi IQ as cited by J. Philippe Rushton offers a potential strategy for exploring the vexed question of non-Ashkenazi Jews: compare their scores with non-Jews who have surrounded them historically. That work could be extended by calculating not raw IQ means, but ratios of Jewish to non-Jewish IQ’s within culturally meaningful geographic areas. Doing that calculation accurately presents many methodological difficulties, and good data may be too sparse, but the intriguing hypothesis to be explored is that the ratios will be roughly the same everywhere. The estimated Ashkenazi mean of 110 translates to a ratio of 11:10 in Europe and the United States. If non-Ashkenazi Jews with a mean of 100 were historically surrounded by a people with a mean of 91, the ratio would be identical. Since the IQ means of the non-Jewish populations of North African and Middle Eastern countries are estimated to be well below 100, the hypothesis is not implausible on its face.