The study, published in Nature, contradicts a previous theory published in 2012 that said putting yourself first was preferred.
"We found evolution will punish you if you're selfish and mean," said lead author Christoph Adami, a Michigan State University professor of microbiology and molecular genetics.
Adami and Arend Hintze, the two MSU researchers in charge of study, used evolutionary game theory (EGT) to show how co-operative populations tend to fare better and be more successful than selfish ones.
Game theory is a branch of mathematics that deals with the statistics of decision-making.
Researchers used a classic test used in game theory called the "prisoner's dilemma," where two prisoners in a hypothetical scenario are offered their freedom if they inform on the other. The party who informed will only get freedom, however, if the other does not choose to do the exact same thing. If both prisoner's inform on each other they will receive some time. If both remain silent they will both receive less time.
Mathematician John Nash said since there was no way for the two prisoners to communicate and plan what they would say, the best strategy would be to only think of yourself — since co-operation would hinge on assuming you could predict the action of the other party.
According to Adami, that particular anecdotal game fails at taking communication — a real world factor — into account. If they were allowed to communicate, the outcome would be quite different because "communication is critical to co-operation."
Selfish would eliminate each other
A 2012 study said that the method that helped one party "win” against the less selfish, co-operative one was called “zero-determinant” (ZD). That concept led Adami and Hintze to ask questions about how effective the ZD actually was.
To test their theory they used high-powered computers with thousands of games, eventually concluding that ZD strategies were ineffective if both players were using them.
In further tests, the researchers found that even when selfish players (using ZD) eliminated players who were co-operative, they eventually had to evolve as well, otherwise selfish players would essentially eliminate each other and go extinct.