Empirical Evidence of Upward Social Comparison in a Prisoner’s Dilemma Game

A large body of work has offered compelling evidence of the influence of social context on individual decision-making, but the reasons why individuals tend to cooperate with others remain elusive. The prisoner's dilemma constitutes a powerful, yet elementary, social game to study the drivers underlying cooperation. Here, we empirically examined a prisoner's dilemma game where small groups of participants played with controlled, virtual players over a series of rounds. Toward investigating how individual decisions on cooperation are influenced by others, the virtual players were engineered so that they would have a higher cumulative score than some participants and a lower cumulative score than others. Our results corroborate upward social comparison theory, whereby only participants who had a lower cumulative score than cooperating virtual players displayed an increased tendency to cooperate. Overall, our experimental findings indicate that the players' cumulative score plays a critical role within the prisoner's dilemma game, thereby offering a mean for increasing cooperation. For practitioners, this finding sheds light on how players' cumulative score alone modulates decision-making processes toward choices that are suboptimal for the individual, but optimal for the entire group.