The terms nested sets, partitive frequencies, inside-outside view, and dual processes add little but confusion to our original analysis (Gigerenzer & Hoffrage 1995; 1999). The idea of nested set was introduced because of an oversight; it simply rephrases two of our equations. Representation in terms of chances, in contrast, is a novel contribution yet consistent with our computational analysis System 1.dual process theory” is: Unless the two processes are defined, this distinction can account post hoc for almost everything. In contrast, (...) an ecological view of cognition helps to explain how insight is elicited from the outside (the external representation of information) and, more generally, how cognitive strategies match with environmental structures. (shrink)

The phenomenon of base-rate neglect has elicited much debate. One arena of debate concerns how people make judgments under conditions of uncertainty. Another more controversial arena concerns human rationality. In this target article, we attempt to unpack the perspectives in the literature on both kinds of issues and evaluate their ability to explain existing data and their conceptual coherence. From this evaluation we conclude that the best account of the data should be framed in terms of a dual-process model of (...) judgment, which attributes base-rate neglect to associative judgment strategies that fail to adequately represent the set structure of the problem. Base-rate neglect is reduced when problems are presented in a format that affords accurate representation in terms of nested sets of individuals. (shrink)

In the rationality debate, Gerd Gigerenzer and his colleagues have argued that human’s apparent inability to follow probabilistic principles does not mean our irrationality, because we can do probabilistic reasoning successfully if probability information is given in frequencies, not percentages (the natural frequency hypothesis). They also offered an evolutionary argument to this hypothesis, according to which using frequencies was evolutionarily more advantageous to our hominin ancestors than using percentages, and this is why we can reason correctly about probabilities in the (...) frequency format. This paper offers a critical review of this evolutionary argument. I show that there are reasons to believe using the frequency format was not more adaptive than using the standard (percentage) format. I also argue that there is a plausible alternative explanation (the nested-sets hypothesis) for the improved test performances of experimental subjects—one of Gigerenzer’s key explananda—which undermines the need to postulate mental mechanisms for probabilistic reasoning tuned to the frequency format. The explanatory thrust of the natural frequency hypothesis is much less significant than its advocates assume. (shrink)

Gerd Gigerenzer's views on probabilistic reasoning in humans have come under close scrutiny. Very little attention, however, has been paid to his evolutionary component of his argument. According to Gigerenzer, reasoning about probabilities as frequencies is so common today because it was favored by natural selection in the past. This paper presents a critical examination of this argument. It will show first, that, _pace_ Gigerenzer, there are some reasons to believe that using the frequency format was not more adaptive than (...) using the standard (percentage) format and, second, that Gigerenzer's evolutionary argument and his other arguments such as his historical description of the notion of probability are in tension with each other. (shrink)