Aaaand...the question of demographics predictably comes up. I won't venture my own opinion on that aspect of the discussion but I will say that IQ tests carry a significant cultural bias. It's unavoidable. I don't know if they still print them but I used to be quite a whiz with those Dell logic puzzles (cross-sums being my very favourite kind of puzzle). That experience helped a lot with acing the IQ "test" that I had to take to get into a computer programming course way back in the 90s. Fun times.
How statistically significant is that though? There surely seems to be far greater variation in per-capita economic output on a state-by-state basis than there is in average IQ at any rate.