Read Lionel Shriver's satire,
Mania: "... it's not like we don't all know which kids are total pea-brains. The teachers are always calling on them, and no matter what they say it's always, 'Ooh, Jennifer, that's so wise!' And then wen one of the thickos claims five times seven is sixty-two, our math teacher says, 'Excellent! That's one answer, and a very
good answer. So would anyone else like to contribute a different answer?'"
Video interview with the author here: https://www.youtube.com/watch?v=N17dF847rpM
My wife was an elementary school teacher [over the decades, she taught all grades, except K, eventually] in a largely working class, rural district way back in the day.
She claims the teachers could pretty well guess which [a very few] kids would end up in jail as adults. I tend to believe her.