A large literature suggests that many individuals do not apply Bayes Rule correctly when making decisions that depend on them correctly pooling prior information and sample data. We replicate and extend a classic experimental study of Bayesian updating from psychology, employing the methods of...

Several authors have reported an unconditional size effect in returns around earnings announcements. In this study we show how this finding can be understood as resulting from ambiguity aversion. We hypothesize that analyst forecasts for smaller companies are relatively more ambiguous; hence...