Gerd Gigerenzer (born 3 September 1947) is a German psychologist who has studied the use of bounded rationality and heuristics in decision making. Gigerenzer is director emeritus of the Center for Adaptive Behavior and Cognition (ABC) at the Max Planck Institute for Human Development and director of the Harding Center for Risk Literacy, both in Berlin. Gigerenzer investigates how humans make inferences about their world with limited time and knowledge. He proposes that, in an uncertain world, probability theory is not sufficient; people also use smart heuristics, that is, rules of thumb. He conceptualizes rational decisions in terms of the adaptive toolbox (the repertoire of heuristics an individual or institution has) and the ability to choose a good heuristics for the task at hand. A heuristic is called ecologically rational to the degree that it is adapted to the structure of an environment. Gigerenzer argues that heuristics are not irrational or always second-best to optimization, as the accuracy-effort trade-off view assumes, in which heuristics are seen as short-cuts that trade less effort for less accuracy. In contrast, his and associated researchers' studies have identified situations in which "less is more", that is, where heuristics make more accurate decisions with less effort. This contradicts the traditional view that more information is always better or at least can never hurt if it is free. Less-is-more effects have been shown experimentally, analytically, and by computer simulations. Biography Education Gigerenzer received a master of arts and a doctor of philosophy in psychology from the University of Munich in 1974 and 1977, respectively. He received the postdoctoral degree of habilitation (full professor qualification) at the university's department of psychology in 1982. Academic career Previously working at the University of Munich, Gigerenzer moved to the University of Konstanz in 1984 and to the University of Salzburg in 1990. From 1992 to 1995 he was Professor of Psychology at the University of Chicago and has been the John M. Olin Distinguished Visiting Professor, School of Law at the University of Virginia. In 1995 he became director of the Max Planck Institute for Psychological Research in Munich, and in 1997 director of the Max Planck Institute for Human Development in Berlin. Since 2009 he has been director of the Harding Center for Risk Literacy in Berlin, which moved in 2020 to the University of Potsdam. Heuristics With Daniel Goldstein he first theorized the recognition heuristic and the take-the-best