there's no such thing as a free lunch
Interactions and competition amongst kin can create complex societies with impressive technological systems, such as those of the social insects. Other animals, including primates, share resources with non-kin too. Hence they, as we do, have to manage the complexity of social as well as kin interactions within an ever-shifting psychological environment.
Game theory throws an interesting light on possible 'rules' for these interactions. The biologist Gerald Wilkinson noted the calculations vampire bats
make about sharing their highly perishable food source (blood) appear
to fit with the tit-for-tat algorithm of game theory. It appears that
bats and other social animals, including ourselves, operate reciprocal
altruism; that is to say, if an animal offers a valuable resource to
another unrelated animal, this will need to be reciprocated for the
offer to occur again; i.e. there is no such thing as a free lunch.
The key players who developed game theory and its associated concept of reciprocal altruism were a Manhattan Project pioneer John von Neuman, a young but troubled mathematical genius called John Nash, the SALT negotiator, Professor Robert Axelrod and fictional Prisoners with a Dilemma (note the capital letters) . . . along with Anatol Rapoport a quite remarkable Russian who had been a virtuoso pianist and, more recently, other men and women - evolutionary psychologists, economists and other social scientists.