> Contribution of education to this 15 points might be just few points.
It certainly isn't genetics. You're not going to cause a population-wide one sigma increase within a single generation using any genetic mechanism.
> It's not about IQ, also, was it ever replicated?
Yes, this has been replicated repeatedly. As far as IQ, if you apply for a private school that uses IQ tests for admission, you will find that all of them explicitly forbid test coaching because it is well known that it works. Even a video will cause large gains. https://www.sciencedirect.com/science/article/abs/pii/S01602...
It certainly isn't genetics. You're not going to cause a population-wide one sigma increase within a single generation using any genetic mechanism.
> It's not about IQ, also, was it ever replicated?
Yes, this has been replicated repeatedly. As far as IQ, if you apply for a private school that uses IQ tests for admission, you will find that all of them explicitly forbid test coaching because it is well known that it works. Even a video will cause large gains. https://www.sciencedirect.com/science/article/abs/pii/S01602...