In 1998, Professor David Hirshleifer of the Michigan Business School, and two co-authors, published a paper titled "Investor Psychology and Security Market Under- and Overreactions." This paper has been widely recognized as the first explanation of the seemingly contradictory behavior in asset prices (under- and overreactions to different news) based on two well documented behavioral biases. The biases outlined in the paper are overconfidence (regarding the precision of one's private information) and biased self-attribution. The former leads to well documented evidence of long-term overreaction (price reversals), while the latter causes underreaction (momentum) in the medium term. This paper was the first widely recognized paper in finance based on departures from rational behavior and provided a compelling explanation for seemingly anomalous behavior in asset prices.