Adaptive Expectations, Confirmatory Bias, And Informational Efficiency
The authors study the informational efficiency of a market with a single traded asset. The price initially differs from the fundamental value, about which the agents have noisy private information (which is, on average, correct). A fraction of traders revise their price expectations in each period. The price at which the asset is traded is public information. The agents' expectations have an adaptive component and a social-interactions component with confirmatory bias. They show that, taken separately, each of the deviations from rationality worsen the information efficiency of the market.