003 - Will Laboratory Medicine be saved by the brain or by the gut of its professionals? Gerd Gigerenzer: the father of gut feelings and of the fast and frugal heuristics
Autor(s): Romolo M. Dorizzi
Issue: RIMeL - IJLaM, Vol. 4, N. 1, 2008 (MAF Servizi srl ed.)
. Gerd Gigerenzer, Director of the Center for Adaptive Behavior and Cognition at the Max Planck Institute for Human Development in Berlin and professor of Psychology at Berlin, Chicago, Salzburg, studied the use of heuristics in decision making especially in medicine. He has authored several books intended for a lay audience on this subject of heuristics and decisionmaking, including Simple Heuristics That Make Us Smart and the most recent Gut Feelings: The Intelligence of the Unconscious. Gut feelings are based on surprisingly little information. Yet experiments demonstrate that less time and information can improve decisions. Less is more means there is some range of information, time, or alternatives where a smaller amount is better even if it does not mean that less is necessarily more over the total range. For instance, if one does not recognize any alternative, the recognition heuristic cannot be used. Less is more approach contradicts two core beliefs held in our culture: more information is always better and more choice is always better. While economists think that more information is always better unless the costs of acquiring further information surpass the expected gains, according to Gigerenzer more knowledge may help to explain yesterday’ s market by hindsight, but not to predict the market of tomorrow. The german psychologist investigated topics such as the benefits of “ignorance” the cognitive limitations, the freedom-of choice paradox, the benefits of simplicity, the information costs. Good intuitions, gut feelings, ignore information and spring from rules of thumb that extract only a few pieces of information from a complex environment. A large part of Gigirenzer’s work is devoted to medicine. He explains that the statement “If a woman has breast cancer the probability that she will have a positive result on mammography is 90% “is often confused with: “If a woman has a positive result on mammography the probability that she has breast cancer is 90%.” That is, the conditional probability of A given B is confused with that of B given A. Many doctors, many patients and many politicians have trouble distinguishing between the sensitivity, the specificity, and the positive predictive value of test - three conditional probabilities. Women in high risk groups are told that bilateral prophylactic mastectomy reduces their risk of dying from breast cancer by 80% but the real percentage is 4%. This fight against the innumeracy in health system makes Gigezenzer’s thinking consistent with the Evidence Based Laboratory Medicine.