Kin selekcija, altruizam i teorija igara

In evolutionary biology, an organism is said to behave altruistically when its behaviour causes fitness benefit to the recipient, at a cost to its own. Biologists became very interested in that kind of behaviour because it seemed contradictory to Darwin's theory of evolution. Why would an organism behave in a way that reduces its fitness and why has it not been eliminated by natural selection? First theories favored group selection, whose idea was that an organism sacrifices itself for the benefit of the group, but the shortcomings of the idea soon became obvious. First important progress was made by W. D. Hamilton in 1964., who proposed kin selection theory. By helping a relative, an organism increases chances in propagation of mutually shared genes, which in turn increases its inclusive fitness. He proposed a model which takes into account cost and benefit for altruist and recipient, and their relatedness (r x B > C). But altruism was noticed between non-kin too, so kin selection couldn't grasp the whole picture. That part of the puzzle was solved by Robert Trivers in 1971., who proposed reciprocal altruism theory. An organism will help another if he can expect help in return. If two organisms manage to establish cooperation, both of them benefit so cooperation will be maintaned. His theory was supported with evidence from evolutionary game theory, and today it's considered a main explanation for altruism and cooperation, next to kin selection.