Hilaire Belloc, in Europe and the Faith: Sine auctoritate nulla vita (without authority, no life) doubts the influence of genetics, but does accept linguistic coherence, the core of culture.
Well then he'd fit right in with Jared Diamond of "Guns, Germs, and Steel" who seriously proffered the notion that the inhabitants of New Guinea (who still practice cannibalism among other things) have just as much native intelligence as northern Europeans. They're just in the wrong part of the world.
Diamond argues that (favorable) geography plays the most important factor in the development of peoples and nations. You see New Guinea, despite being an island, has no access to the sea. /s