By all accounts, every German woman and female child the Red Army came across was raped communally. The estimates of come in between 2 million and 300,000 russian rape babies. The E German population was around 18 million in 1950, occupied by soviet forces. Many young German men were dead from the war. Those babies are what, 70+ now? So 3+ generations? Seems a pretty ideal situation to significantly change the admixture.

I'm not saying that communism and authoritarianism didn't stunt IQ, just that reunification should have ameliorated the gap significantly, yet it seems to have remained wider than pure environmental factors would suggest.

And yes, IQ didn't develop equitably between central and eastern Europeans, and that too may have been environmental in nature.

Absolutely.