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Abstract:
The assumption of perfectly rational representative agents is now commonly questioned. This paper explores the equilibrium properties of boundedly rational heterogeneous agents. We combine an adaptive learning process in a modified cobweb model within a Stackleberg framework. We assume that there is an asymmetric information diffusion process from leading to following firms. In contrast to a simple cobweb model which has a unique REE, our model may produce multiple restricted perceptions equilibria (RPE). However, a unique and learnable RPE, under certain conditions, can exist in our model. In addition, the following firms' forecasts can confound the leading firms' forecasts -- when the following firms misinterpret information coming from the leading firms. We refer this situation to the boomerang effect. We also find that the leading firms' mean squared forecast error can be even larger than that of following firms if the proportion of following firms is sufficiently large in the market.

adaptive learning, bounded rationality, heterogeneous expectations, least squares learning, rational expectations

Abstract:
I introduce Expectational Business Cycles where aggregate activity fluctuates due to learning, heterogeneous updating rules and random changes in the social norm predictor. Agents use one of two updating rules to learn the equilibrium values while heterogeneity is dictated via an evolutionary process. Uncertainty of a new equilibrium, due to a shock to the structure of the economy, results in a sudden decrease in output. As agents learn the equilibrium, output slowly increases to its equilibrium value. These business cycles arrive faster, are longer and more severe as agents possess less rationality.

Adaptive learning, aggregate fluctuations, heterogeneous expectations

Abstract:
We examine global economic dynamics under learning in a New Keynesian model in which the interest-rate rule is subject to the zero lower bound. Under normal monetary and fiscal policy, the intended steady state is locally but not globally stable. Large pessimistic shocks to expectations can lead to deflationary spirals with falling prices and falling output. To avoid this outcome we recommend augmenting normal policies with aggressive monetary and fiscal policy that guarantee a lower bound on inflation. In contrast, policies geared toward ensuring an output lower bound are insufficient for avoiding deflationary spirals.

Adaptive learning, fiscal policy, indeterminacy, monetary policy, zero interest rate lower bound