Game Theory and the Selfless Yeast
In class so far, we have discussed how game theory can help predict human behavior in certain situations — rational players must arrive at one of the Nash equilibriums. Interestingly, equilibriums in nature can also be explained through game theory.
A group of MIT researchers found that a population of yeast would always reach an equilibrium where there are two groups of yeast using different survival schemes — cooperators and cheaters. Yeast who are cooperators secret an enzyme that would break sucrose into consumable, simple sugar. Cheaters, on the other hand, consume the simple sugar that drifted away and are not consumed by the cooperators. At first glance, it is puzzling as to why cooperatoring behavior survived the scissors of evolution. When individuals in a population compete for limited food sources, why would some individuals expense their own energy to benefit others?
This perplexing question was finally answered when researchers discovered that yeast that are cooperators get preferential access to the simple sugar, allowing them to compete with the cheaters. Using what we learned in class, it is now easy to understand that the game that cooperators and cheaters play is actually a different one than what scientists had previously imagined. Even when all other yeasts cheat, the yeast left gains more by cooperating rather than cheating. This is exactly like the hawk-dove game that we learned in class: (cheat, cooperate) and (cooperate, cheat) are mutual best responses. Using game theory, we can see how the coexistence of cheaters and cooperators is inevitable.
Article: https://phys.org/news/2009-04-game-theory-cooperative-behavior-meshes.html