Expectation Formation Under Uninformative Signals
研究发现，即使信号不携带相关信息，人们仍会据此更新期望，且更新方向取决于信号的好坏，这解释了为何在信息易得但难验证的环境中（如网络媒体）人们会形成并坚持错误信念。
How do individuals process nondiagnostic information? According to Bayes’ theorem, signals that do not carry relevant information are treated as if no signal occurred. This paper provides evidence that individuals update their expectations even after observing uninformative signals. Importantly, the direction in which they update depends on the valence of the signal. Prior beliefs become more optimistic after desirable uninformative signals and more pessimistic after undesirable uninformative signals. Our results provide novel insights why individuals form and entertain false beliefs in environments in which potentially new information is easily accessible but costly to verify (e.g., online media). This paper was accepted by George Wu, behavioral economics and decision analysis. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.03367 .