Models of social behaviour based on game theory

摘要

The emergence of cooperation created a puzzle for generations of scientists across several disciplines (Pennisi 2009). Why an individual would sacrifice herself for another when natural selection favors the survival of the fittest? Charles Darwin himself remarked the paradox of a worker bee that labors for the good of the colony, although its efforts do not lead to its own reproduction. He proposed that selection might favor families whose members were cooperative, and it is accepted today that kinship helps explain cooperation. But defectors, those who benefit without making a sacrifice, are likely to evolve because they will have an advantage over individuals who spend energy on helping others, therefore jeopardizing the stability of any cooperative effort. Yet cooperation and apparently even altruism have evolved and remained, on any level of biological organization. Without cooperation, genomes, cells or multicellular organims would have never been formed (Maynard Smith and Szathmary 1995). There are numerous examples of cooperation in both animal and human kingdoms and to this date there is no widely acceptable explanation why. The suitable theoretical framework to address this issue is evolutionary game theory (Axelrod and Hamilton 1981; Axelrod 1984), which has been intensively used for this research during recent years. Its main virtue consists in that it allows to pose the dilemmas involved in cooperation, and the mechanisms proposed to explain it, in a simple and rigorous manner. In what follows, we will introduce the basic concepts from game theory and then we will discuss some possible mechanisms which lead to the promotion of cooperation. ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------