>>106474605
>it can't change more than one deviation
no, it can hit the roof or drop dead too.
Its just a dumb metric that everyone is obsessed over because it has been used since a long time and there is no accurate alternative to it.
>genetics put a hardcap on it
genetics is one of the things but not the only thing that puts the cap.
Even people born with high IQ genes will become dumb overtime before reaching adulthood if their culture and society forces them to believe they are supposed to be stupid and behaving as such is the only way to co-exist. Environment plays a huge role too.
Anyway, its not solely the IQ you should be looking at. Overtime, skills can be developed and improved by low IQ people as well which makes IQ a bad metric to focus on.