In describing how people generalize from observed samples of data to novel cases, theories of inductive inference have emphasized the learner's reliance on the contents of the sample. More recently, a growing body of literature suggests that different assumptions about how a data sample was generated can lead the learner to draw qualitatively…

Language can be used to express broad, unquantified generalizations about both categories (e.g., "Dogs bark") and individuals (e.g., "Daisy barks"). Although these two classes of statements are commonly assumed to arise from the same linguistic phenomenon--"genericity"--the literature to date has not offered a direct…

The quest for determining the degree of learning difficulty associated with different types of categories has been instrumental in our understanding of human categorization behavior and, more broadly, human generalization. For instance, we now know that the topological nature of the dimensions (e.g., whether these are integral or separable) that…

A major question for the study of learning and memory is how to tailor learning experiences to promote knowledge that generalizes to new situations. In two experiments, we used category learning as a representative domain to test two factors thought to influence the acquisition of conceptual knowledge: the number of training examples (set size)…

In five experiments, we established and explored the contrast diversity effect--the effect of diversity of negative evidence on inductive inferences drawn from a single observation of a target exemplar. In Experiments 1 through 3, we show that increasing the diversity of negative evidence in a contrasting category led people to infer that a target…

Learning naturalistic categories, which tend to have fuzzy boundaries and vary on many dimensions, can often be harder than learning well defined categories. One method for facilitating the category learning of naturalistic stimuli may be to provide explicit feature descriptions that highlight the characteristic features of each category. Although…

Learning to categorize perceptually similar stimuli can result in people becoming more sensitive to differences along perceptual dimensions that are relevant to category membership and/or less sensitive to equivalent differences along irrelevant perceptual dimensions. These effects of acquired distinctiveness and acquired equivalence may be caused…

Building conceptual knowledge that generalizes to novel situations is a key function of human memory. Category-learning paradigms have long been used to understand the mechanisms of knowledge generalization. In the present study, we tested the conditions that promote formation of new concepts. Participants underwent 1 of 6 training conditions that…

Category learning is fundamental to cognition, but little is known about how it proceeds in real-world environments when learners do not have instructions to search for category-relevant information, do not make overt category decisions, and do not experience direct feedback. Prior research demonstrates that listeners can acquire task-irrelevant…

In judgment and categorization, the task is to infer the criterion value of an object based on cues. The cognitive mechanisms underlying such inferences are often distinguished in terms of whether they rely on an abstracted cue-criterion rule or on retrieving exemplars. The use of cue-based and exemplar-based strategies (and the associated…

Hampton (1988) discovered that people are subject to "overextension"--they categorize some things as falling under a conjunction (e.g., they categorize chess as a "sport which is also a game") but not as falling under both of the corresponding conjuncts (e.g., they do not categorize chess as a "sport"). Although…

The findings of Shepard, Hovland, and Jenkins (1961) on the relative ease of learning 6 elemental types of 2-way classifications have been deeply influential 2 times over: 1st, as a rebuke to pure stimulus generalization accounts, and again as the leading benchmark for evaluating formal models of human category learning. The litmus test for models…

Stimuli that are processed fluently tend to be regarded as more familiar and are more likely to be classified as old on a recognition test compared with less fluent stimuli. Recently it was shown that the standard relationship between fluency and positive recognition judgments can be reversed if participants are trained that previously studied…

Accounts of learning and generalization typically focus on factors related to lasting changes in representation (i.e., long-term memory). The authors present evidence that shorter term effects also play a critical role in determining performance and that these recency effects can be subdivided into perceptual and decisional components.…