We thank Scott Gronlund and Frank Durso for suggesting that we look at MINERVA2 as a starting point for our model. We are deeply indebted to

Diagnostic hypothesis-generation processes are ubiquitous in human reasoning. For example, clinicians generate disease hypotheses to explain symptoms and help guide treatment, auditors generate hypotheses for identifying sources of accounting errors, and laypeople generate hypotheses to explain patterns of information (i.e., data) in the environment. The authors introduce a general model of human judgment aimed at describing how people generate hypotheses from memory and how these hypotheses serve as the basis of probability judgment and hypothesis testing. In 3 simulation studies, the authors illustrate the properties of the model, as well as its applicability to explaining several common findings in judgment and decision making, including how errors and biases in hypothesis generation can cascade into errors and biases in judgment.

The theory of probabilistic mental models (PMM; G. Gigerenzer, U. Hoffrage, & H. Kleinbölting, 1991) has had a major influence on the field of judgment and decision making, with the most recent important modifications to PMM theory being the identification of several fast and frugal heuristics (G. Gigerenzer & D. G. Goldstein, 1996). These heuristics were purported to provide psychologically plausible cognitive process models that describe a variety of judgment behavior. In this article, the authors evaluate the psychological plausibility of the assumptions upon which PMM were built and, consequently, the psychological plausibility of several of the fast and frugal heuristics. The authors argue that many of PMM theory's assumptions are questionable, given available data, and that fast and frugal heuristics are, in fact, psychologically implausible.

No abstract

In this research, we examined the role that individual differences in working memory (WM) capacity, the strength of alternatives, and time constraints play in probability judgment and subadditivity. With a laboratory-based learning task, Experiment 1 revealed that the degree to which participants' probability judgments were subadditive was negativelycorrelated with a measure of WM capacity, even when variance due to short-term memory capacity was removed. In addition, participants were more subadditive when the viable alternativeswere all rather weak. Experiment 2 extended the WM-capacitysubadditivity correlation to a population judgment task and revealedthat subadditivity increases when the judgment task is performed under time constraints. Results support a model that assumes that people make probability judgments by comparing the focal hypothesis with relevant alternatives retrieved from long-term memory and that people high in WM span include more alternatives in the comparison process. Time constraints are assumed to truncate the alternative generation process, leading to fewer alternatives being recalled from long-term memory.