Human IQ has been going up at a very fast rate for the last 100 years. Kids tested by the Army being enlisted for WW1 who had a mean score of 100(by definition) in 1917 now would have a mean score of lss than 80. Tons of interesting work on why IQ is shooting up, but it definitely is NOT genetics.

This is known as the Flynn effect. Here is the wikipedia entry in case you want more details:

https://en.wikipedia.org/wiki/Flynn_effect

Video games like Civilization and Myst etc, probably add 5 to 10 IQ points to kids. My 9 year old knew all about Greek triremes. Me: What the heck is a trireme?

Most if what people call “genetic effects” are actually “genetic-by-environment” interaction effects. Chane the environment and you change the APPARENT heritability. Good example is the genetics of substance use disorders which range from 30 to 60%—-but IF AND ONLY IF there are drugs around to which you are exposed in YOUR environment.?

Same applies to good and bad schools.

Don’t confuse knowledge with intelligence.

Knowing what a trireme isn’t a sign of intelligence, it’s trivia.

Being able to figure out how to build a trireme is intelligence.

And I don’t mean looking up instructions and doing, I mean being able to reconstruct the knowledge from baser principles. This is not to say you or your son aren’t intelligent, just that knowing about triremes isn’t a sign of it.