Effects of group sensitivity on cooperation in N-person snowdrift game with dynamic grouping

Abstract

In nature and society, individuals are often tempted to exploit free-riding opportunities. Previous studies have shown that, without additional measures like spatially restricted interactions and costly punishment, defection should be more prevalent than cooperation. By incorporating group sensitivity and size adjustable interacting groups into the N-person snowdrift game, we have studied the coevolution of the preferred group sizes and the frequencies of cooperators. It is found that the widespread of cooperation is closely related to the degree of an individual’s group sensitivity. In comparison with a weak or a strong sensitivity, a moderate group sensitivity can greatly promote cooperation. With the rise of the group sensitivity, the step-like changes of the frequencies of cooperators and the average preferred group sizes are found. A theoretical analysis reveals that an individual’s group sensitivity may lead to a decrease in the preferred group size and accordingly an increase in cooperation. A functional relation between the frequencies of cooperators and the average preferred group sizes is found.