Let me preface this letter by saying that I know a few things about math, a little about psychology, but not that much about linguistics.
However, I believe that basic mathematical skills (that is, basic arithmetic, geometry, and algebra - any math course up to the calculus, which is usually touched on in the final year of high school or the first year of university) can be learned by pretty much anyone. It's just a matter of how much work you want to put into it and the resources that you want to devote to it. I suspect that these are the skills being tested in said studies.
When it does come down to it, math is a cheap subject to teach (also a relatively cheap subject to finance research on). Given that high school math texts barely reach the seventeenth century, it's not like they go out of date. I wouldn't be surprised if resource-poor China did concentrate its efforts on teaching mathematics, while resource-rich America tends to favour more concrete studies (such as biology, physics, chemistry) among the hard sciences.
There also seems to be a correlation between availability of resources and success in higher mathematics. I've counted up Fields medal winners since its inception in 1936 (not delivered in 1940 and 44 due to war) and found the following approximate breakdown by national origin:
US 11 France 7 UK 7 USSR/Russia 7 Japan 4 Germany 3 Scandinavia 3 Belgium 1 China 1 Italy 1
The top nations are those that can afford to subsidize sticking large numbers of pure mathematicians in one place, and fields winners overwhelmingly come from that place. Russia also has a cultural mathematical tradition, although we'll see if that endures the current political chaos.
Marco
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> Marco Anglesio | Hard reality has a way <
> mpa at the-wire.com | of cramping your style. <
> http://www.the-wire.com/~mpa | --Daniel Dennett <
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