Alexandre V. Morozov – Rutgers University
Date/Time/Location
Thursday, March 6th, 2025, 12:10 pm; Hill Center 705
Evolution of cooperativity in the game of Prisoner's Dilemma
Complex life would be impossible without cooperation at all levels of biological organization: genes cooperate in creating regulatory networks and signaling pathways, cells become parts of multicellular organisms, animals enter into complex cooperative arrangements both within and between species. Cooperation is ubiquitous in modern human societies and is credited with the development of civilization. However, Darwinian evolution is believed to promote selfish behavior - societies of cooperators are vulnerable to cheaters that ultimately take over, destroying cooperation in biological populations. This apparent paradox has occupied the center stage of evolutionary biology for more than half a century. A well-known model of this paradox is the celebrated Prisoner's Dilemma, an elegant mathematical framework in which (so it was believed) cheaters always win, even though being cooperative brings greater rewards. Here we demonstrate that it is possible to achieve high levels of cooperativity in the game of Prisoner's Dilemma without introducing any additional assumptions about genetic relatedness, population structure, or game strategies. The only requirement is that the willingness to cooperate has to vary depending on the opponent, instead of being blind to the opponent's physical appearance and patterns of behavior. This variance drives the population to a sequence of persistent cooperative states - a starting point, perhaps, for more stable modes of cooperation observed in animal and human societies.