They are only modified if there is some form of selection though, like for example some people say of the Dutch and their height.

In modern times it is more likely that culture and education augments genetics such that your violent tendencies are repressed, you are brought up leading a soft and comfortable life, taught to be polite and kind, etc. Contrast to maybe someone brought up in a warzone or some other place.

I mean post apocalyptic shows like the walking dead express this quite well (at least the first few seasons) where once society falls it's just a free for all and back to our roots again.