J Levitt proposes an equation to estimate a chess player’s IQ from their chess score.
It suggests that chess grandmasters probably have IQs above 160.
We would expect them to need much more practice to achieve a level of proficiency similar to those chess masters, and indeed that seems like what happens.
(all of this is confounded by them being women and almost all the other equally-good chess masters being men.
According to Wikipedia: Polgár began teaching his eldest daughter, Susan, to play chess when she was four years old.
[EDIT: Thanks to a few people who pointed out some problems with my math here (1, 2, 3).
I still think that having three supergenius-IQ kids when you and your spouse show no signs of being a supergenius yourself (Laszlo Polgar’s daughters could beat him at chess by the time they were 8) is pretty unlikely, but I admit not impossible.
The Polgar sisters’ IQs might have been a permissive factor in allowing them to excel, but it didn’t necessitate it. Malcolm Gladwell uses the Polgars as poster children for his famous ‘10,000 hours of practice makes you an expert at anything’ rule.
The Polgars had 50,000 hours of chess practice each by the time they were adults, presumably enough to make them quintuple-experts.