Some things never change: Everyone is different.

Henrich realized that if the Machiguenga results stood up, and if similar differences could be measured across other populations, this assumption of universality would have to be challenged.Henrich had thought he would be adding a small branch to an established tree of knowledge. It turned out he was sawing at the very trunk. He began to wonder: What other certainties about “human nature” in social science research would need to be reconsidered when tested across diverse populations?

via Why Americans Are the Weirdest People in the World.