A funny thing to think? Compare our ancestors' social lives to our own.
In many ways, your tribe is the people in whose presence you repeatedly spend comfortable time.
I seriously wonder whether it's possible for a modern college-educated working American to truly feel anything like our ancestors' family ties. The family farm (like in The Horse Whisperer) may have been the last arrangement that permitted it.
Radically distributed social emotions are the modern direction. And, I, of course, love to take new directions to extremes...