Neo-Fisherian Policies and Liquidity Traps
在新凯恩斯框架下分析了流动性陷阱的两种类型（基本面驱动与信心驱动），发现信心陷阱中利率上升反而具有扩张通胀效应，且不同陷阱类型下货币与财政政策效果截然相反，为区分陷阱类型提供了可检验的推论。
Liquidity traps can be either fundamental or confidence-driven. In a simple, unified New Keynesian framework, I provide the analytical condition for the latter’s prevalence: enough shock persistence and endogenous intertemporal amplification of future (“news”) shocks, making income effects dominate substitution effects. The same condition allows neo-Fisherian effects (expansionary-inflationary interest rate increases), which are thus inherent in confidence traps. Several monetary and fiscal policies (forward guidance, interest rate increases, public spending, labor tax cuts) have diametrically opposed effects according to the trap variety. This duality provides testable implications to disentangle between trap types; that is essential, for optimal policies are also conflicting across trap varieties.