Wealth and cultural/familial values are the major culprits.
Wealth and cultural/familial values are the major culprits.
Said another way, if you give tests that ask people about stuff that neither they nor most of the people they know care about, you shouldn't be surprised by bad and/or inconsistent results.
America, in trying to promote the idea that anyone can become anything, has quite thoroughly quashed the idea that it is of any benefit to come from a "cultured" background; and, thereby, has devalued the concept of acquiring a Liberal Arts education as a necessary stepping stone in dynasty-building.
There are probably benefits to this, but there are also obvious drawbacks.
Now look at popular US culture nowadays. People are told they can be whatever they want to be, and losers are given participation trophies. Comfort and inclusion is seen as more important than competition and self-control. Our culture is changing massively, and it's showing in our test scores.
[1] https://skeptics.stackexchange.com/questions/36760/were-48-o...
Drive matters. A family with expectations, and generations of educational aspirations matter, if you’re trying to excel.