Cooperating for direct fitness benefits.
Hammerstein
P
P
Institute for Theoretical Biology, Humboldt University Berlin, D-10115 Berlin, Germany.
Leimar
O
O
D000533:Altruism; D000818:Animals; D001522:Behavior, Animal; D005075:Biological Evolution; D003299:Cooperative Behavior; D005716:Game Theory; D006801:Humans; D008954:Models, Biological; D012641:Selection, Genetic