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1 This Pew article is a start

2 First, IQ is highly heritable (about 80% in Western countries) but the environment does matter, especially in third world countries. Most MENAs living in those countries probably have a worse environment on average than African Americans (lower nutition, education, and incomes). So their scores are probably depressed by these somewhat.

Second, African Americans are about 25% white on average. This gets them from a probable genetic IQ of 80 to a genetic IQ of 85. More on this in Richard Lynn's Race Differences in Intelligence.

Third, while there is a lot less genetic distance between MENA caucasians and European caucasians on average than there are between, say Africans and Europeans, it does not necessarily follow that MENA IQ scores must also be very close to Europeans. There could be more variation in intelligence-linked genes between these groups than other genes. So looking at the variation overall does not tell us the full story on cognitive differences. Ashkenazi Jews for instance cluster even closer to whites and they have a probable genetic IQ of about 110

3 How would you respond to studies like this one that argue that twin studies are methodologically flawed

The main criticism of studies like these is that twin studies assume the twins raised together share an "equal environment" that is basically the same, and that this assumption is invalid. This is obviously a very weak criticism that is probably wrong. If you share the same parents, the same SES, and go to probably the same schools, what "environmental" influences are we really expecting could impact IQ (or in this case, political views?) If you really want to talk about this study in-depth try posting one not behind a paywall, but that's the gist

Let's pretend the criticisms have merit and twin studies aren't that great for establishing heritability estimates. This doesn't really improve the case for egalitarians that much because they still cannot explain the bulk of IQ differences between races or an abundance of other corroborating evidence using environmental variables. So their case is basically unchanged since the 1960s where they are searching for some environemental "x-factors" theyve largely not been able to find - despite searching for many decades

Also this abstract mentions polygenic scores and lack of evidence from them, but is from 2008. Since then there has been more progress on explaining IQ and IQ differences using polygenic scores e.g. [1] [2] [3]

4 Other than places like 8kun, 4chan, or Storefront you have some communities in Ruqqus or Parler