It really doesn't take much deprivation to lower IQ. If you didn't have modern healthcare, you wouldn't even notice such. I think it's also entirely possible low IQ groups can't provide that on their own. So there is something of a feedback loop. A high IQ group could share medical care and nutrition information with a lower IQ group and possibly raise a higher IQ generation, if the genes were there, who could modernize.
when a population remained low iq forever, I doubt there would be hidden high iq genes left, low iq populations tend to engage in behaviors that eliminate the intellectuals
It really doesn't take much deprivation to lower IQ. If you didn't have modern healthcare, you wouldn't even notice such. I think it's also entirely possible low IQ groups can't provide that on their own. So there is something of a feedback loop. A high IQ group could share medical care and nutrition information with a lower IQ group and possibly raise a higher IQ generation, if the genes were there, who could modernize.
when a population remained low iq forever, I doubt there would be hidden high iq genes left, low iq populations tend to engage in behaviors that eliminate the intellectuals