Gerd Gigerenzer I Think , Therefore I Err

limitations of our cognitive system? Or are errors indispensable parts of every intelligent system? From the first perspective, all errors are at best unnecessary and at worst harmful. Consider an error commonly made by children. When asked to find the sum of 1/2 and 1/3. the answer is often 2/5. This is called the freshman error of adding numerators and adding denominators {Silver. 1986). But blunders are not limited to children. After the invention of the telephone, a group of British experts concluded that this invention had no practical value, at least in their country: "The telephone may be appropriate for our American cousins, but not here, because we have an adequate supply of messenger boys" {Sherden. 1998: 175). In 1961. President John F. Kennedy is reported to have asked himself "How could I have been so stupid?" after realizing how badly he had miscalculated when he approved the Bay of Pigs invasion planned by the CIA (Janis and Mann. 1977: xv). Blunders like these seem to be unnecessary as well as embarrassing, and every intelligent system would work better without them. In this view, to err is not to think.