Gaowang Wang

What we don’t know doesn’t hurt us: rational inattention and the permanent income hypothesis in general equilibrium

This paper derives the general equilibrium effects of rational inattention (or RI; Sims 2003, 2010) in a model of incomplete income insurance (Huggett 1993, Wang 2003). We show that, under the assumption of CARA utility with Gaussian shocks, the permanent income hypothesis (PIH) arises in steady state equilibrium due to a balancing of precautionary savings and impatience. We then explore how RI affects the equilibrium joint dynamics of consumption, income and wealth, and find that elastic attention can make the model fit the data better. We finally show that the welfare costs of incomplete information are even smaller due to general equilibrium adjustments in interest rates.

Rational Inattention and the Dynamics of Consumption and Wealth in General Equilibrium

We use a recursive utility version of a basic Huggett (1993) model to study the cross-sectional dispersion of consumption and wealth (relative to income). The basic model implies too little dispersion compared to the data, whereas a one-parameter extension to include rational inattention (limited information processing) delivers a better fit to both facts in general equilibrium. In particular, intertemporal substitution plays an important role in determining the two key dispersion moments via affecting the degree of optimal attention in equilibrium. Alternative models that rely on habit formation, incomplete information about current income, or borrowing constraints are not consistent with the facts we document.