are we mindful and emphatic by nature?
"By nature" is not a useful qualifier here. Maybe it's nature, maybe it's nurture; either way, I for one think it would be better if more people were "mindful and empathetic", regardless of whether you attribute that gain to societal encouragement or the removal of societal discouragement.
As long as people are part of the same tribe. Plenty of small communities who aren't terribly empathetic to outsiders, minorities or foreigners.