Risk-preference–driven participate willingness provides alternative routes to solve social dilemma

Risk preference is the level of risk that a person is prepared to accept when pursuing his goals. In economic interaction, risk preference determines willingness to participate and affects the evolution of cooperation. In particular, most people may take a moderate attitude towards the risk and only choose to participate in part. Based on such reality, this work abstracts this behavior as a partial cooperation strategy and analyzes the evolution of cooperation. Essentially, partial cooperation is a balance between participation and non-participation by the cooperator. From the micro-dynamic characteristics of the simulation results, the partial cooperation players play different roles in the dynamic system. Specifically, when the willingness to participate is insufficient (sufficient), these partial cooperation players will replace the position of the loners (cooperators) in the evolutionary dynamics, which further leads to the special cyclic invasion. Moreover, as the willingness to participate increases, the percentage of free riding (cooperation) for the second time gradually decreases until it disappears.