Game Theory and Prisoner’s Dilemma in Nature
https://www.quantamagazine.org/20150212-game-theory-calls-cooperation-into-question/
The long-held belief that cooperation is beneficial to the survival of individuals in nature has been brought into question by physicist Freeman Dyson and computer scientist William Press. They have used the prisoner’s dilemma to explain how cooperation in nature works. Selfish strategies that benefit an individual would seem to aid in survival of a species in general, but there has been research showing that animals can act selfishly while also fostering a cooperative community, and that this creates the optimal chances of survival.
Press and Dyson, however, suggested that the strategies most conducive to survival were those that were selfish ones that led to extortion, rather than cooperation. They defined extortion as a player always choosing to defect according to a certain set of probabilities, and this would allow that player to control that game’s outcome. They would need to take into account how much they could defect without completely demotivating the other player. If one player is an extortionist, the other player is forced to cooperate in order to receive the best payoff.
This has been challenged by theoretical biologist Joshua Plotkin, who points out that there are many examples in nature of cooperative behavior allowing for species success. Vampire bats will share their blood meal to those who do not catch prey, and there are even some species of birds that help raise another’s brood.
Plotkin and colleague Alexander Stewart analyzed the effects of these same traits on evolving groups (specifically groups of vervet monkeys and vampire bats). They incorporated the strategy of generosity. One utilizing a generous strategy would cooperate whether his opponent cooperates or defects. They found that generous strategies were much more successful in evolving populations. They also proposed that while extortion does well when facing one opponent, in a larger population, where an extortioner faces another extortioner, both will defect and both will end up with a smaller payoff.