There was a thread here a few weeks ago where someone mentioned a specific group that does select for intelligence and consequently has statistically above-average IQ.

That thread was shouted down because people basically said "even if that's true, we don't want to talk about it because it's close to scientific racism." That may be fine and I can see how that topic is counter productive sometime but in this case I think it goes to the parent's point, that some populations DID evolve a higher mean intelligence and are reaping the rewards.