Here is a fragment from A Game of Giants by Tim Urban:

So while kindness, in all its manifestations—care, altruism, compassion—was an important survival trait in a world where well-functioning groups were necessary for survival, universal kindness probably wasn’t a great survival trait. Inevitably, other tribes would be selectively kind, shedding all of that kindness when dealing with other tribes. And when a kind tribe faces off against a ruthless tribe, the ruthless tribe usually wins.

The evolutionary sweet spot probably wouldn’t have been kindness or empathy or compassion or cooperation—it would have been to have these traits on a toggle switch. To be micro-kind and macro-ruthless.

When I look around, I see evidence of this toggle switch everywhere. Notice how easily people who are normally compassionate drop that compassion when thinking and talking about members of a political party they hate—the “Them” political party? How these people are all about forgiveness with people they see as part of “Us” but are fine with permanent, lifelong consequences for enemies of that group? How they’re so good at seeing the story behind the story when they hear about criminals they consider part of “good guy” groups, but always seem to see the worst superficial caricature in wrongdoers from groups they don’t identify with? It happens on a smaller scale too, like when people who have spent their lives showing no compassion or understanding for a certain type of outsider suddenly have a warm heart when someone in their family ends up as part of that group.

This seems depressingly accurate to me, but let’s imagine another scenario. The “selectively kind” group may grow curious and/or desperate, while the “always kind” group may have enough resources to offer help and enough confidence with their state-of-the-art defense. In such conditions a win-win outcome may become possible via a mutual exploration. A dreadful stranger may become the dear familiar.