Bad news, Randians: A study suggests there is no evolutionary value to selfishness. Researchers at the University of Pennsylvania used a classical game theory match-up called "Prisoner's Dilemma" and mathematical models to demonstrate why "cooperation and generosity have evolved in nature," Penn said in a statement. Associate professor Joshua Plotkin and postdoc researcher Alexander Stewart, both of Penn's Department of Biology in the School of Arts and Sciences, analyzed the outcome of Prisoner's Dilemma as played by a large, evolving population of players. Here, by the way, is Prisoner's Dilemma:
Two members of a criminal gang are arrested and imprisoned. Each prisoner is in solitary confinement, unable to speak or exchange messages with the other. Police admit they don't have enough evidence to convict the pair on the principal charge. They plan to sentence both to a year in prison on a lesser charge. Simultaneously, the police offer each prisoner a Faustian bargain:
* If A and B both confess the crime, each of them serves 2 years in prison
* If A confesses but B denies the crime, A will be set free whereas B will serve 3 years in prison (and vice versa)* If A and B both deny the crime, both of them will only serve 1 year in prison
The point of the game is to study how people choose whether to cooperate. As Penn explains, "In the game, if both players cooperate, they both receive a payoff. If one cooperates and the other does not, the cooperating player receives the smallest possible payoff, and the defecting player the largest. If both players do not cooperate, they receive a payoff, but it is less than what they would gain if both had cooperated. In other words, it pays to cooperate, but it can pay even more to be selfish. The italics are mine, because that last part appears to offer a rationale for selfishness. Building on previous research, Plotkin and Stewart "began to explore a different approach to the Prisoner's Dilemma":
Instead of a head-to-head competition, they envisioned a population of players matching up against one another, as might occur in a human or animal society in nature. The most successful players would get to "reproduce" more, passing on their strategies to the next generation of players.
The two researchers soon determined that "extortion strategies wouldn't do well if played within a large, evolving population because an extortion strategy doesn't succeed if played against itself," Penn said. So they looked at "generous" strategies in games with multiple players, where players are willing to cooperate with opponents and will suffer more than their opponents if they don't cooperate. They simulated the effects of generous strategies on players and then built a mathematical proof demonstrating the evolutionary value of generosity. "Our paper shows that no selfish strategies will succeed in evolution," Plotkin said. "The only strategies that are evolutionarily robust are generous ones." Selfish people of the world, consider yourselves warned. Now read this: