[allendoerfer]

The reverse is true, too: Want better performance than people of the same age? Have had more training than them.

I suspect this applies especially to language or logic related tasks.

We will likely never find out, variance seems to be extremely high, while the actual differences are very low.

[eru]

There are actual studies. Lots of professional athletes were in the older part of their cohort when they were younger. So the effect Terr_ described seems to outweigh the one you describe.