Evolution of cooperation under threshold public goods game.

When the number of cooperators does not reach the collective target, resulting in the collective risk social dilemma, the self-organizing behavior of the group leads to the loss of collective interest and the government intervention leads to the increase of collective interest. For these two situations, we study the evolution of cooperation under threshold public goods game in well-mixed population. The results show that the introduction of the threshold makes it possible to generate complex dynamics with two interior equilibria in the replication equation. For self-organizing behavior, increasing the threshold is a double-edged sword. Although raising the threshold may increase the level of cooperation, the risk of dominance of defection also increases. For government intervention behavior, increasing the threshold significantly promotes cooperation. The common result is that individuals tend to free-ride when the group size increases. In addition, the greater the impact of the two behaviors on collective interest, the more conducive to promoting cooperation. When there are fewer initial cooperators, the government should intervene in time to generate cooperation. When there are more initial cooperators, self-organizing behavior is more conducive to attracting cooperators than government intervention. We hope that the model and results proposed in this paper can contribute to addressing the challenges posed by global issues such as climate change and the degradation of the ecological environment.