The northwest-southeast cline in Europe and the brain

A friend sent me this amazing study, seems to have been previously overlooked by hereditarians. Bakken, T. E., Dale, A. M., Schork, N. J., & Alzheimer’s Disease Neuroimaging Initiative. (2011). A geographic cline of skull and brain morphology among individuals of European Ancestry. Human heredity, 72(1), 35-44. Background Human skull and brain morphology are strongly…

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Of cats and dogs and men

Genetic variation between populations/races of a species is a nice single summary statistic about how large between population phenotypic differences to expect. In case of humans, this value (Fst, the fixation index) is about 15%. This finding is due to Lewontin (1972) and is now mindlessly repeated (Lewontin’s fallacy) as some kind of slam dunk…

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Paige-Harden, Turkheimer and the psychometric left

Kathryn Paige Harden is professor of psychology who belongs to the Turkheimerian ‘left psychometrics’ school. I’ve discussed the odd behavior of Eric Turkheimer before, but since then I found a rather amazing essay: The Search for a Psychometric Left 1997 (the journal seems to no longer exist). It’s definitely worth reading in its entirely, but…

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A partial test of DUF1220 for population differences in intelligence?

You might have heard the DUF1220 hypothesis, it goes something like this: DUF1220 is a copy number variant poorly tagged by arrays, and thus would not be captured well by typical GWASs for education/IQ. Comparative species data suggests strong selection for DUF1220 with increased intelligence/brain size. There’s some data showing a relationship between IQ in…

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FAQ for Dunkel et al 2019 Ashkenazim polygenic score for intelligence

Dunkel, C. S., Woodley of Menie, M. A., Pallesen, J., & Kirkegaard, E. O. (2019). Polygenic scores mediate the Jewish phenotypic advantage in educational attainment and cognitive ability compared with Catholics and Lutherans. Evolutionary Behavioral Sciences. So predictably, our study on Jewish IQ has elicited some rather harsh (and in some cases moralistic) criticisms from…

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What you can’t say: genetic group difference edition

Paul Graham‘s 2004 essay What you can’t say had a big influence on me and remains my favorite essay. In he argued essentially that popular morality shows fashion tendencies i.e. that it varies over time but for no evidence-linked reason. What is at one time considered a grievous moral evil is later considered not a…

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Environmentalists like admixture analysis too (until they don’t)

See previous post about quotes from the medical genetics and physical anthropology literature on admixture analysis and the causal interpretation. There’s quite a few older admixture studies that examined relationships between racial ancestry and intelligence. Most of these used quite crude methods such as interviewer judgement. Some used a better method, namely objectively measured skin…

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