You would think, all else being equal, that IQ would be the lowest at the center position in basketball, since there's such a premium on height there that everything else is at a discount.
- David Robinson scored 1320 on the SAT (old style scoring, equivalent to the low 1400s today) and graduated from the Naval Academy with a degree in math.
- George Mikan, the NBA's first superstar, was a successful lawyer after his playing days were over.
- Bill Walton attended Stanford Law School while out from the NBA with injuries.
- Wilt Chamberlain and Bill Russell always gave the impression in interviews of being sharp-witted men. Granted, my old impressions aren't terribly trustworthy, but these two guys did a lot of interviews back in the day. Russell was frequently called upon by the media to serve as a Yoda-like hipster guru who could explain the great social changes of the late 1960s and early 1970s. Chamberlain was less popular with the press than Russell because he endorsed Nixon, but he always displayed a certain ornery independence.
For the other four in the consensus top 10 (Moses Malone, Shaq, Hakeem Olajuwon, and Patrick Ewing), I can't think of any evidence for one way or another. My vague impression from living in Houston in the 1970s was that Moses Malone wasn't considered the sharpest tool in drawer (but he could vacuum up offensive rebounds!)
As an aside, I'll toss in the story of somebody who isn't a top 10 center, but has had a long career despite playing very little basketball as a youth: Dikembe Mutumbo from the Congo. He got into Georgetown as a regular admittee to study diplomacy. Coach John Thompson just about had a heart attack when he saw this unknown 7'-2" black guy walking across campus with a stack of books in his arms. That's why Georgetown had its unwieldy Twin Towers formation with Mutumbo and Alonzo Mourning -- nobody had recruited Mutumbo. He just showed up.
At other positions, you can pick out all-time greats who clearly had something going on upstairs, like Dave Bing, who became a successful steel mill owner. But, there seem to be more above average IQ types at center. At minimum they aren't less common at center, even though you'd expect height to dominate all else most at that position.
It's possible that hard-working book-smart guys do better at center than at other positions. Playing with your back to the basket is rather unnatural, and typically requires extensive coaching and drilling, whereas you can become a star guard or forward just by scrimmaging constantly.
More generally, I have this vague hunch that athletes below 75 or 80 in IQ are much more likely to fail to make the big time than ones over 90 because the low IQ ones screw up so badly -- get hooked on drugs, go to prison, get seriously hurt in a fight or an accident, or just miss various opportunities through knuckleheadedness -- that they blow their opportunities.
You might be able to do an interesting nature-nurture study by tracking extremely tall young men in a basketball crazy society to see what happens to people given lots and lots of breaks in life. First, you'd need to know what % of young fellows of a certain height -- say two meters or taller, make it to each level up the ladder in basketball. Then look at success rates by IQ. And look at the real failures among the super tall -- those who wind up in prison -- by IQ.
I don't think we have the data to do it in the U.S., but this study might be possible in a European country with universal conscription where they measure every 19-year-old male's height and give him an IQ test. It would have to be a country that is wild about basketball, too. All my Lithuanian and Croatian readers who are looking for social science dissertation topic, get cracking!