Conflict between groups of players in coupled socio-economic and ecological dynamics

Conflict among multiple groups is a major source of difficulty in environmental conservation. People are often divided into various groups that have different social factors, sometimes leading to differences in the degree to which they cooperate in environmental conservation. This obstructs the social consensus needed to solve the environmental problems. Here we study the coupled dynamics of human socio-economic choice and lake water pollution, and examine the magnitude of the difference in cooperation levels between two groups. In the model, many players choose between a costly but cooperative option and a selfish option. The former results in a reduced phosphorus discharge into the lake. Each player's choice is affected by an economic cost and social pressure. Social pressure is a psychological factor that promotes cooperation: it becomes stronger when more players in the society are cooperative (conformist tendency) and when the problem at hand is a greater concern to society. In the model, two groups sometimes show large differences in their cooperation levels even when both have exactly the same social factors. However, cooperation levels are more likely to differ between groups that have different social factors. Enhancement of the cross-group conformist tendency is the most effective way to minimize differences in cooperation levels and to mitigate conflict between groups.