Cognitive Bias in the Laboratory Security Market

The Efficient Market Hypothesis has been a kind of pivot both for academic research and for policy making concerning stock market for the last decades. But this hypothesis recently keeps being criticized both from archival and experimental viewpoints. In this paper we also criticized it based on psychological experiment. Concretely we show that the appearance of three kinds of cognitive bias has a possibility in real stock markets and we also demonstrate that even information efficiency is a kind of problem concerning human psychology. We conclude that government disclosure policy of stock market must take psychological aspect of investors into consideration.