2009-12-19 20:59:50 UTC
Mutually beneficial - a behaviour that increases the direct fitness of both the actor and the recipient
Selfish - a behaviour that increases the direct fitness of the actor, but the recipient suffers a loss
Altruistic - a behaviour that increases the direct fitness of the recipient, but the actor suffers a loss
Spiteful - a behaviour that decreases the direct fitness of both the actor and the recipient
This classification was proposed by W. D. Hamilton. He proposes that natural selection favours mutually beneficial or selfish behaviours. Hamilton's insight was to show how kin selection could explain altruism and spite.
Social evolution is also often regarded (especially, in the field of social anthropology) as evolution of social systems and structures