Consumption Externalities and Macrceconomic Dynamics

本研究的目的是探讨消费外部效应在代际重叠经济中的作用。已有的关于具有消费外部性的宏观经济模型的研究大多采用了具有代表性的代理人模型。由于在具有代表性的代理人经济体中，私人消费水平和平均消费水平彼此重合，在上述大多数研究中，消费外部性的影响大多是定量的，而不是定性的。通过引入代理人消费活动之间的外部效应，我们扩展了标准的两期生存OLG资本积累模型。代表性代理人和OLG环境的关键区别在于，消费的同时外部效应涉及OLG经济中的代际外部性和代内外部性。本项目的总体结论是，OLG经济的动态行为在很大程度上取决于消费外部效应的具体表现。我们发现，即使是简单的模型也可能产生多个稳态和平衡的不确定性。此外，模型经济体的政策含义将从根本上不同于在代表代理对应经济体中获得的政策含义。我们已经在OLG经济体的不同偏好和技术规格的替代设置的背景下证实了这些事实。

The purpose of this study is to explore the role of consumption external effects in overlapping generations economies. Most of the existing investigations on macrodynamic models with consumption externalities have utilized the representative agent models. Since the private and average levels of consumption coincide each other in the representative agent economies, the effects of consumption externalities are mostly quantitative rather than qualitative in most of the foregoing studies. We extend the standard two-period lived OLG models of capital accumulation by introducing external effects among consumption activities of the agents. The key difference between the representative agent and the OLG settings is that the contemporaneous external effects of consumption involve the intergenerational as well as intragenerational externalities in the OLG economy.The general conclusion of this project is that the dynamic behaviors of OLG economies heavily depend on how the consumption external effects are specified. We have found that even simple models may yield multiple steady states and indeterminacy of equilibrium. In addition, policy implications in the model economies would be fundamentally different form those obtained in the representative agent counterpart. We have confirmed these facts in the context of alternative settings of OLG economies with various specifications of preferences and technologies.