Behavioral Theories of the Business Cycle

We explore the business cycle implications of expectation shocks and of two well-known psychological biases, optimismand overconfidence. The expectations of optimistic agents are biased toward good outcomes, whereas overconfident agentsoverestimate the precision of the signals that they receive. Both expectation shocks and overconfidence can increasebusiness-cycle volatility, while preserving the model's properties in terms of comovement and relative volatilities.In contrast, optimism is not a useful source of volatility in our model. (JEL: E3) (c) 2007 by the European Economic Association.