title: Representation facilitates reasoning: what natural frequencies are and what they are not.
abstract: A good representation can be crucial for finding the solution to a problem. Gigerenzer and Hoffrage (Psychol. Rev. 102 (1995) 684; Psychol. Rev. 106 (1999) 425) have shown that representations in terms of natural frequencies, rather than conditional probabilities, facilitate the computation of a cause's probability (or frequency) given an effect--a problem that is usually referred to as Bayesian reasoning. They also have shown that normalized frequencies--which are not natural frequencies--do not lead to computational facilitation, and consequently, do not enhance people's performance. Here, we correct two misconceptions propagated in recent work (Cognition 77 (2000) 197; Cognition 78 (2001) 247; Psychol. Rev. 106 (1999) 62; Organ. Behav. Hum. Decision Process. 82 (2000) 217): normalized frequencies have been mistaken for natural frequencies and, as a consequence, "nested sets" and the "subset principle" have been proposed as new explanations. These new terms, however, are nothing more than vague labels for the basic properties of natural frequencies.
authors.affiliation: Max Planck Institute for Human Development, Lentzeallee 94, 14195, Berlin, Germany. hoffrage@mpib-berlin.mpg.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hoffrage
authors.forename: Gerd
authors.initials: G
authors.lastname: Gigerenzer
authors.forename: Stefan
authors.initials: S
authors.lastname: Krauss
authors.forename: Laura
authors.initials: L
authors.lastname: Martignon
mesh_terms: D001499:Bayes Theorem; D003210:Concept Formation; D006801:Humans; D011337:Probability Learning; D011340:Problem Solving