Except in the paleolithic these people would be your extended family, the friends you grew up with, etc. And because of the cultural homogeneity of such societi

Except in the paleolithic these people would be your extended family, the friends you grew up with, etc. And because of the cultural homogeneity of such societies, you would get along better with them than people get along with their families today. In the modern context, these would be people you selected.