And yet, we are the only hominins that survived, most likely because we were the friendliest and least distrustful of outsiders who weren't from our own tribe. Clearly, some of this impulse for Us and Them is deeply ingrained, but there's also a lot of cultural stuff that reinforces it. Conservatives tend to view the world much more in this way than liberals.

I love the ideas you presented for finding ways to move away from that sort of mentality.