We asked 169 participants to spontaneously categorize nine sets of items. A category structure was assumed to be more intuitive if a large number of participants consistently produced the same classification. Our results provide a rich empirical framework for examining models of unsupervised categorization—and illustrate a corresponding profound modeling challenge. We provide a preliminary exam...

Psychological essentialism states that certain categories are assumed to have an underlying hidden reality (or "essence") that defines objects’ identity (Gelman, 2003; Medin & Ortony, 1989). Everyday classification, on the other hand, must be based on the features of objects that are observable. How do we reconcile these facts? One way is to assume that essential features cause observable ones,...

Beller, Bender, and Medin question the necessity of including social anthropology within the cognitive sciences. We argue that there is great scope for fruitful rapprochement while agreeing that there are obstacles (even if we might wish to debate some of those specifically identified by Beller and colleagues). We frame the general problem differently, however: not in terms of the problem of re...

Even if we don’t like it, we often face counterexamples to the inferences we have made or would like to make. With the exception of the SimProb model (Blok, Medin & Osherson, 2007), models of inductions to date have predominantly focused on the relevance of positive evidence to the inference process. Here we provide data from single and double premise arguments in a category-based property indu...

Traditional classification learning studies tell us that people learn to attend to the diagnostic features of exemplars (Kruschke, 1992; Medin & Schaffer, 1978; Shepard, Hovland, & Jenkins, 1961). But recent research has discovered that the learning task influences what information people learn about categories (Markman & Ross, 2003). A learning task can either be the primary goal or be inciden...

We report a case of a 59 year-old patient in a condition of acute myocardial infarction with ST elevation, in a cardiogenic shock, with multiple cardiac arrests in mechanism of ventricular fibrillation with a significant chest wall deformity caused by Heine-Medin disease in childhood. To our knowledge, this is the first case report of a patient in critical condition with a considerable pectu...

Both real-world category knowledge and instance-based sample data are often available as sources of inductive inference. In three experiments using natural social categories, we test the influence of generalcategory knowledge on the use of category instances to make property inductions both to other category members and to others in the population. We find that a category's coherence--the exten...

(}luck and Bower (1988) suggestmi that through the use of the Rescorla-Wagner learning rule, a connectionist network might be ~ble to model the inverse base-rate phenomenon found by Medin and Edelson (1988). I prove that a network of the type that they proposed does not capture this effect. However, one can also prove that with additional assumptions about the encoding of features, the Rescorla...