Theories of categorization have typically focused on the internal structure of categories. This paper is concerned with the external structure of categories. In particular , it is suggested that many categories specify the relational role that is played by category members. To support this claim, the paper distinguishes between traditional feature-based categories, relational categories (which specify a relational structure) and role-governed categories (which specify that an item plays a particular role within a relational structure). After discussing the relationship among these types of categories, the implications of this view for the study of category learning and category use are discussed.

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This paper describes a model of how people classify items in single and combined categories, and an experiment testing that model. This model (the diagnostic evidence model) sees classification as a generative process: one in which items can be classified in completely new combinations of categories for which no previous examples have been seen. In the experiment people learned to identify (imaginary) diseases, and then classified patient descriptions into single disease categories or into combinations of those categories. The results supported the generative view of classification: people had no difficulty in classifying items in completely new combinations of disease categories. Further, the diagnostic evidence model was able to accurately predict people's classification performance in the experiment, both for single disease categories and for new disease combinations. The ability to form, use, and combine mental representations is a basic part of human cognition. To take an...

ssing. We suggest that some types of similarity are determined automatically. When the cognitive system recognizes similarities, they influence cognitive processing, even when the person does not intend for their processing to be affected by similarities. In order to support this claim, we first outline three different approaches to similarity. Then, we examine how similarity can influence both low-level processes like attention and memory retrieval and higher cognitive processes like analogical reasoning and decision making. Next, we explore a number of examples in which cognitive processing is influenced by the presence of similarities in a stimulus set. Finally, we broaden the discussion to include similarities in more deliberate cognitive processes. Three Approaches to Similarity Representation and Similarity When a person makes a similarity comparison, the result is typically both a judgment of similarity and also some awareness of the commonalities and differences of the pair com

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Cognitive approaches to creativity are discussed as they relate to an important task of entrepreneurs: generating novel and useful ideas for business ventures. Attention is given to the paradoxical role of knowledge, which can either enhance of inhibit creativity, as well as to the properties of knowledge and a selected set of processes that influence the originality of newly generated ideas. Experimental findings are discussed along with suggestions about how those findings might be translated to practical applications.

This paper presents a set of experiments we carried out recently with Divago, a system we have been developing and which has, as an underlying motivation, the goal of being a computational model of creativity. This model is expected to be able to generate novel concepts out of previous knowledge. Here we show its behaviour with a large dataset constructed independently by other researchers consisting of over 170 nouns. Each noun is represented with a syntax that is equivalent to the one adopted for Divago. We apply a two step experimentation procedure, which starts by "training" the system with "preferred outcomes" and then allowing it to do free generation, constrained by the pragmatic goal of a given query. We evaluate and make a short discussion on the results under well defined criteria of novelty and usefulness.

ABSTRACT: An important source of creativity in concept combination is emergence: Novel features are often attributed to a concept combination that are not attributed to either of its constituent concepts. For instance, a Harvard-educated carpenter is judged to be nonmaterialistic, though neither Harvard-educated people nor carpenters in general are thought to be nonmaterialistic. Emergent attributes may thus be considered creative in that they are novel to the combination. This investigation examined 2 linguistic factors believed to promote such emergence. The relevance and typicality of modifiers were inversely related to the emergence of novel attributes, such that irrelevant and atypical modifications increased emergence. Antonymous and anomalous combinations produced the most emergent attributes. The cognitive mechanisms by which novel attributes emerge, and their relation to creative cognition, are discussed. Uttering a word is like striking a note on the keyboard of the imagination. —Wittgenstein (1953, p. 4) As Wittgenstein (1953) aptly indicated, language is a creative endeavor. The language producer must create coherent combinations of concepts in order to convey a meaningful utterance, and likewise the comprehender must re-create that compound meaning from the meanings of its individual concepts. An important source of creativity in concept combination is emergence: Novel features are often attributed to a concept combination that are not attributed to either of its constituent concepts. For instance, a Harvard-educated carpenter is judged to be nonmaterialistic, though nei-

This paper describes a new model of classification and typicality which explains a number of empirical results in simple and combined categories. In this exemplarbased model, classification is based on the diagnostic and plausible evidence of attributes. The model explains the family resemblance structure of simple categories, the overextension of typicality in some combined categories, and people's ability to judge typicality in "empty" combined categories (combinations of categories which have no members in common). The model also explains the influence of category overlap on the overextension of combined categories, and the observed dominance of some categories in combination. Finally, the model accounts for the interesting finding that "emergent" attributes in combination (attributes true of a combination but not of its constituents) are often accessed more rapidly than non-emergent attributes (true of the combination and its constituents). An exemplar model of classification 3 I...