The same goes for language skills, by the way. In the US, 21% of adults are illiterate, and 54% of adults have literacy below sixth-grade level.[1] This is higher than in other developed countries. For example, in Germany, 10% are illiterate, and 32% have literacy below fifth-grade level.[2]

General intelligence also seems to have been trending downward since the 1970s (the reverse Flynn Effect)[3]. It has been measured in the US and Europe.

So, while it is true that the education system and other factors have an influence, the idea that "everybody is capable of X" is wrong and harmful. It's the equivalent of "nobody needs a wheelchair" or "everybody can see perfectly." People are different. A lot of nerds only hang out with other nerds, which screws up their perception of society.

[1]: https://www.thenationalliteracyinstitute.com/post/literacy-s... [2]: https://leo.blogs.uni-hamburg.de [3]: https://www.sciencedirect.com/science/article/pii/S016028962...

That certain countries both now and in the past have had significantly higher mathematical ability among the general population and much higher proportions going on to further study suggests that ability isn’t innate but that people don’t choose it. In the Soviet Union more time was spent teaching mathematics and a whole culture developed around mathematics being fun.

>A nice sentiment but clearly a large % of people never do learn even basic mathematical thinking and seem very confused by it

Any healthy/able individual could learn to deadlift twice their bodyweight with sufficient training, but the vast majority of people never reach this basic fitness milestone, because they don't put any time into achieving it. There's a very large gap between what people are capable of theoretically and what they achieve in practice.

> So is there some scientific study backing up the claim that all these people could easily learn it [emphasis added]

Who said it would be easy?

We are not really taught (thought) to think, we are taught to memorize. Until one actually tries to think, you really can't tell if they're able to do it.

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