Sure, playing chess needs intelligence, dedication, and good chess players are smarter than an average person. But it’s waaaay exaggerated in movies. I’m a math researcher, and in any movie, my department will be full of chess geniuses. But in reality, only about 10% of them even play chess.
So… disclaimer first! I have played chess but only a year or so; I got into chess during the pandemic and had a peak ELO of ~1600+ on chess.com and 1900+ on Lichess; probably translates to a classical ELO of ~1200 (competition is tough in classical…). Obviously I’m not remotely a good player, but I can hold my ground. I also had to do a neuropsych evaluation recently for mental health reasons, so I spent the last month of my free time looking into research of intelligence (g factor, IQ tests, the disturbing history, etc…) for my own curiosity. So I might have a bit of knowledge on this… but:
For the most part chess is its own unique skills and is unrelated to “smartness”. Nevertheless, I think chess might be related to probably just one or two specific narrow fields of intelligence. Being good at chess requires one to be knowledgeable of various chess openings (memorization, working memory), extremely strong pattern recognition (Magnus Carlsen is really good at this; AlphaZero was literally all pattern recognition due to the way it works), and being able to see 5, 10, or even 15 steps ahead and consider all the rational options (again, working memory)
I just took the WAIS-V test two weeks ago for my psych eval, and they do indeed test for working memory and pattern recognition in specific sub-tasks. However the difference is… IQ tests are never meant to be practiced as they measure a type of “potential” if you may, but chess is all about what you actually play on the board. Sure maybe if ppl were literally just given the rules and had no prior exposure then a smarter person might spot a forced checkmate faster, but ppl do pratice for the game… In fact, the advice people used to give to get better at chess is… to do more puzzles
Sooo… methinks an intelligent person might have a slight edge training themselves to do the above, but there is probably otherwise very little association. After a certain point intelligence itself probably has no influence on chess performance whatsoever, and realistically it’s more about “grit”, or how much time/effort someone puts into the game
Aaand… case in point. Apparently Kasparov went through a 3-day intensive intelligence test, but had a really “spiky” profile that is more commonly seen in neurodivergent individuals; scored really high on some categories and abysmally low on others. I saw this random Reddit post which says that Carlsen scored 115(+1SD) on AGCT (a fairly quick and accurate online test), which is not low but not impressive by any means either. Nakamura allegedly got 102 on Mensa Norway’s trial test, which is not as accurate as AGCT but should be fairly good too; 102 is like dead-average