Dynamics of spatial traveler's dilemma games

By examining payoff structures, we elucidate the traveler's dilemma (TD) game. It can be said that the TD game as the 2-player & multi-strategy game is a variant of the donor & recipient game, which itself is a subclass of the 2-player & 2-strategy (2 x 2) prisoner's dilemma, in the sense that the Nash equilibrium and fair Pareto optimum appear on mutual defection and mutual cooperation, respectively. Exploring spatial TD games, we observed that the network reciprocity of TD games can be universally scaled with a single dilemma parameter as can be performed in usual 2 x 2 games. Furthermore, we observed a local peak event reflecting a resurging cooperation fraction with increasing dilemma strength after degradation to a low level. We successfully demonstrate that this is caused by the specific dynamics of TD games created by their specific payoff structure.