We are domesticated animals

[cthulu2016]

8. We have always been social

But we are probably less violent and more controllable today than previously.

Environmental selection can drive evolution very fast in terms of lessening traits within a population. It depends how reliable the environmental factor is.

For instance, if a mad dictator took over the world and had every person over 5'-3" killed or sterilized the average height of the human species would be considerably less a generation later.

Something complex like social behavior takes a long time to develop. But something like over-aggression can be reduced quickly. Not eliminated of course... no more than we have eliminated pets that run away.