Observational Learning with Competitive Prices

Will people eventually learn the value of an asset through observable information? This paper studies observational learning in a market with competitive prices. Comparing a market with public signals and a market with private signals in a sequential trading model, we find that Pairwise Informativeness (PI) is the sufficient and necessary learning condition for a market with public signals; and Avery and Zemsky Condition (AZC) is the sufficient and necessary learning condition for a market with private signals. Moreover, when the number of states is 2 or 3, PI and AZC are equivalent. And when the number of states is greater than 3, PI and Monotonic Likelihood Ratio Property (MLRP) together imply asymptotic learning in the private signal case.