> Not a necessary precondition, it can happen through cultural pressure (also something passed down by the generations in tribes). I don't recall previous poster requiring it happen through gene expression.

I feel it was implied in the vision of competing tribes, which hasn't really been how it works for a long time. But still, whatever the trait transmission mechanism, I don't think the supposed complete out-competing of non-conquest-oriented groups necessary for their hypothesis actually happened at scale. Humans content to "chill out" have persisted for all of recorded history.