Ok, time for a little more science of genetics.
Today Steven Pinker tweeted this.
https://twitter.com/sapinker/status/1021508342869577728
That's fine, published in Nature with like 80 authors. The abstract states:
Quote:
Here we conducted a large-scale genetic association analysis of educational attainment in a sample of approximately 1.1 million individuals and identify 1,271 independent genome-wide-significant SNPs. For the SNPs taken together, we found evidence of heterogeneous effects across environments. The SNPs implicate genes involved in brain-development processes and neuron-to-neuron communication. In a separate analysis of the X chromosome, we identify 10 independent genome-wide-significant SNPs and estimate a SNP heritability of around 0.3% in both men and women, consistent with partial dosage compensation. A joint (multi-phenotype) analysis of educational attainment and three related cognitive phenotypes generates polygenic scores that explain 11–13% of the variance in educational attainment and 7–10% of the variance in cognitive performance. This prediction accuracy substantially increases the utility of polygenic scores as tools in research.
So, if I understand that correctly, they've "isolated" 1272 distinct genes that account for 7-10% of the variance in cognitive performance among individuals. So, is that like a 2 point IQ difference?
Now, consider evolution. One might be able to tell some BS story of the type so beloved by armchair evolutionary biologists that people in Africa (who, again, show major genetic variation) lacked the selection pressures that caused their Asian counterparts to develop "better" cognitive functions. Can one tell that evolutionary story for 1200 distinct genes, a sample that accounts for maybe 10% of "cognitive performance"? Were the evolutionary selection pressures for this subset of genes (or, say, the assumed superset of, say, 10k genes that account for most of "cognitive performance"), all in the same direction that selected for Asian "cognitive performance" over African "cognitive performance". That would be pretty damn incredible from an evolutionary standpoint. One would seemingly expect differences in these 1.2k or 10k genes to vary randomly among the populations, such that the "higher cognitive performance" variant was as likely to be found in one population or another. (And, one wonders what sorts of significant uni-directional variation could take place over say, 50-100k years, a pretty limited time scale but about the longest possible period since the common ancestors of groups were cohabiting.)
Again, to the point that there is actually real science being done on the question of the genetic basis of intelligence (even ignoring some significant potential questions about the linked study), and not simply the uninformed musings of conservative poly sci majors, it seems to point pretty solidly in the no genetic basis for observed differences in intelligence between racial groups.
Wookie, you're probably more current on this stuff than me. Any thoughts?
[Of course, the study is directed to genetic differences among individuals and not "race" groups, so the observed genetic difference could exist within all racial groups. My main point is that even as race is a scientifically dubious category, it's likely even more coherent than "cognitive performance" (which is of course just a proxy operational definition for "intelligence", which has no definition).]
BTW, I believe the majority of "cognitive performance" is likely genetic (assuming a minimally, or sufficiently, enriched environment.) I just don't believe that the relevant genetic differences in thousands of genes will be found to vary in any consistent manner across racial groups, particularly when the members of alleged racial groups are pre-defined (i.e., prior to testing of "cognitive performance") and are drawn from actually different environments (i.e., not just descendants from West-Central Africa living in Georgia, or even the US), where massive environmental effects can actually be minimized.
Last edited by simplicitus; 07-23-2018 at 06:24 PM.