Science Sunday Bonus: 'Generous players: game theory explores the Golden Rule's place in biology'

Fundmental Evolutionary principles may have contributed to humans gravitating towards the Golden Rule: 'Generous players: game theory explores the Golden Rule's place in biology':

Charles Darwin's theory of natural selection seems to describe a brutal world in which creatures compete ruthlessly to promote their own survival. Yet biologists observe that animals and even lower organisms often behave altruistically. A vervet monkey who spots a leopard, for instance, warns his fellow monkeys, even though the call may attract the leopard's attention to the individual. A vampire bat that has hunted successfully shares nourishing blood with a fellow bat that failed to find prey.

Such behavior is obviously beneficial for the species as a whole. However, natural selection postulates that successful organisms act to propagate their own genes. If selfish animals can take advantage of more-generous peers, how has any generous behavior survived the mill of natural selection? Darwin himself pondered this puzzle. Focusing on human evolution, he wrote in 1871 that "he who was ready to sacrifice his life, ... rather than betray his comrades, would often leave no offspring to inherit his noble nature."

Somehow, the altruistic behaviors observed in the wild must benefit the giver as well as the receiver. However, pinpointing how this works in animal populations is a huge challenge. In most cases, it's impossible to measure precisely how an animal's cooperative behavior affects its chances for survival and reproduction.

Now, theoretical research is starting to fill in the picture of how cooperation may survive natural selection. Some of the most illuminating ideas are coming from game theory, the field of mathematics that studies strategic behavior in competitive situations...