War Signals: A Theory of Trade, Trust, and Conflict
构建了一个理论模型，解释内战为何持续：冲突信号破坏种族间信任与贸易，形成恶性循环；意外冲突也会陷入“战争陷阱”，而减少文化障碍、促进贸易和人力资本的政策可降低冲突。
We construct a theory of persistent civil conflicts, where persistence is driven by the endogenous dynamics of inter-ethnic trust and trade. In times of peace, agents belonging to two groups are randomly matched to trade bilaterally. Trade hinges on trust and cooperation. The onset of conflict signals that the aggressor has a low propensity to cooperate, harming future trust and trade. Agents observe the history of conflicts and update their beliefs over time. The theory predicts that civil wars are persistent. Moreover, even accidental con.icts that do not reflect economic fundamentals erode trust, and can plunge a society into a vicious cycle of recurrent conflicts (a war trap). The incidence of conflict can be reduced by policies abating cultural barriers, fostering inter-ethnic trade and human capital, and shifting beliefs. Coercive peace policies such as peacekeeping forces or externally imposed regime changes have instead no persistent effects.