We are generally overconfident; that is, we tend to overestimate how much we know. People often overestimate their ability to predict future events, trust their knowledge more than they should, and believe they have a greater influence on random outcomes than they actually do (so called “ illusion of control ” bias (Langer 1975)). In addition, the overconfidence phenomenon can be reinforced by cognitive biases such as the " self-attribution ” bias, where individuals attribute their successes to their own abilities and blame failures on bad luck, and the " hindsight bias ", where people believe they predicted an event after it has already occurred. (Barberis and Thaler, 2003). Illustrating overconfidence in one’s own skills, and possibly optimism as well, Svenson (1981) finds that 82% of a sample of students placed themselves among the top 30% safest drivers. Overconfidence has also been documented among experts and professionals, including those in the finance pr...