http://conversableeconomist.blogspot.com/2019/01/the-flynn-effect-rising-iq-scores-over.html

“the Flynn effect strongly suggests that differences in measured intelligence are not purely genetic, but also have a strong environmental component.  However, the Flynn effect now seems to be moving in reverse.”

https://www.wsj.com/articles/humans-the-domesticated-primates-11547133935

300k years ago human brain starts shrinking like that of domesticated animals, in connection with losing aggressivness like in domesticated animals -> we self-domesticared