Some of you that are familiar with game theory have heard of ‘prisoner’s dilemma’ which basically gives an example of two people betraying each other in hopes of a greater personal gain when they would actually gain more by cooperating. Now University of Pennsylvania biologists Alexander J. Stewart and Joshua B. Plotkin have applied prisoner’s dilemma to a large, evolving population and they’ve discovered mathematical proof that generous behavior will lead to evolutionary success.
In a report filed in the Proceedings of the National Academy of Sciences, Joshua B. Plotkin explains why there’s an abundance of generosity in nature and how it’s helping evolutionary progress.
Cooperative behavior seems at odds with the Darwinian principle of survival of the fittest, yet cooperation is abundant in nature. Scientists have used the Prisoner Dilemma game, in which players must choose to cooperate or defect, to study the emergence and stability of cooperation. Recent work has uncovered a remarkable class of extortion strategies that provide one player a disproportionate payoff when facing an unwitting opponent. Extortion strategies perform very well in head-to-head competitions, but they fare poorly in large, evolving populations.
Rather we identify a closely related set of generous strategies, which cooperate with others and forgive defection, that replace extortionists and dominate in large populations. Our results help to explain the evolution of cooperation.
If that wasn’t clear enough for you, feel free to go through the endless mathematical formulas in their paper, or check out this nifty graph. Strategies colored light blue or dark blue are good, whereas strategies colored dark blue are both good and evolutionary robust, under weak selection.
Now that researchers Alexander J. Stewart and Joshua B. Plotkin have discovered mathematical evidence that you shouldn’t be selfish putz, perhaps you’ll make a sandwich and split it with a stranger today.