[fnordsensei]

There seems to be a general assumption that the brain is a muscle. If you train a muscle, it’s going to get strong regardless of what you lift with it.

If you train yourself to get better at seeing patterns of dots in boxes, that doesn’t generalize nearly as well as a muscle does. It doesn’t make you a better chess player. There’s plenty of science to back this up.

At large, IQ tests in recruiting are training applicants to be good at IQ tests.

[bmn__]

The three hypotheses you expressed are false.