The evolution of cooperation and tolerance under conditional dissociation in cohesive population

This paper investigates how social cohesion influences the evolution of cooperation and tolerance. We study the public goods game with conditional dissociation mechanism where players opt to leave their groups when the number of defections exceeds their established tolerance thresholds. However, the presence of cohesion acts as a constraint, deterring players from leaving. We deliberately exclude the psychological and social factors but emphasize the most fundamental aspect of cohesion that bonds players to stick together. Thanks to this simplification, we give a concrete calculation method to evaluate the fitness of each strategy in the evolutionary dynamics and draw a series of novel findings. Firstly, the impact of cohesion on cooperation exhibits a non-monotonic pattern in general, which explains why there exist controversies about whether cohesion enhances group performances. Secondly, increased cohesion results in greater success for the less tolerant strategists, which is consistent with a series of studies that support the viewpoint that the collectivism culture is less forgiving than the individualism. Finally, influences of synergy factor and selection intensity under different cohesion levels are also discussed. Overall, these results highlight the importance of incorporating structural social forces like cohesion into evolutionary game theory, even in their simplest forms.