New evidence in game theory suggests that selfishness is a trait prone to lose the evolutionary battle and will eventually disappear as a personality trait, according to researchers at Michigan State University.

"We found evolution will punish you if you're selfish and mean," said lead author Christoph Adami, MSU professor of microbiology and molecular genetics. "For a short time and against a specific set of opponents, some selfish organisms may come out ahead. But selfishness isn't evolutionarily sustainable."

Adami and his colleagues' research, pubished in the journal Nature Communications, falls in line with the old adage "winning isn't everything."

The conclusion goes against the established "Zero Determinant" theory which asserts that the selfish player will always come out ahead of the cooperative player.

One cornerstone of game theory experiments is The Prisoner's Dilemma -- a situation where two friends are held captive in isolation and told they can snitch on their friend and go free while their friend will spend six months in jail. If both prisoner's snitch, they each get three months in jail. If they both stay silent, they each get one month in jail for a lesser offense.

If the two prisoners are allowed to talk to each other, it allows for the establishment of trust and they are more likely to cooperate and forge an alliance. If they remain in isolation, the best strategy is to snitch because it guarantees the snitcher does not get the longer jail term.

The Prisoner's Dilemma allows researchers to study a basic question faced by individuals competing for scarce resources: whether to act selfishly or cooperate?

Cooperating would clearly do the most good for both the individuals, but acting selfishly is tempting.

The researchers used computer models to run thousands of "games" and determined that the Zero Determinant -- or selfish -- strategies would only work for "players" who knew who their cooperative opponent was and beat them by exploiting their weaknesses.

But after a while the selfish players would beat out all the cooperative players, leaving only selfish, Zero Dominant, players left in the game. Without a knowledge of the players, it becomes impossible for Zero Dominant (ZD) strategists to keep winning. At this point, the selfish players would have to change their ways in order to keep winning the game.

"The only way ZD strategists could survive would be if they could recognize their opponents," said co-author Arend Hintze. "And even if ZD strategists kept winning so that only ZD strategists were left, in the long run they would have to evolve away from being ZD and become more cooperative. So they wouldn't be ZD strategists anymore."

The researchers believe their computer models will correlate to studies of living organisms.

"Communication is critical for cooperation; we think communication is the reason cooperation occurs," Adami said.

"It's generally believed that there are five independent mechanisms that foster cooperation. But these mechanisms are really just ways to ensure that cooperators play mostly with other cooperators and avoid all others. Communication is a universal way to achieve that. We plan to test the idea directly in yeast cells."