Are stock prices determined by facts or human nature? - USATODAY.com

Are stock prices determined by facts or human nature? - USATODAY.com: "Wall Street has long liked to portray the markets as fiercely efficient, an instantaneous and dispassionate mechanism for valuing companies....But the past decade has taught us that markets can be anything but rational. So today, behaviorists rule: They tell you that investors hold losing stocks not so much because they're