The category utility hypothesis holds that categories are useful because they can be used to predict the features of instances and that the categories that tend to survive and become preferred in a culture (basic-level categories) are those that best improve the category users' ability to perform this function. Starting from this hypothesis, a quantitative measure of the utility of a category is derived. Application to the special case of substitutive attributes is described. The measure is used successfully to predict the basic level in applications to data from hierarchies of natural categories and from hierarchies of artificial categories used in category-learning experiments. The relationship of the measure to previously proposed indicators of the basic level is discussed, as is its relation to certain concepts from information theory.Categorization is one of the most basic cognitive functions. Why is the ability to categorize events or objects important to an organism? An obvious answer to this question is that categories are important because they often have functional significance for the organism. Another familiar answer is that grouping objects into categories allows for efficient storage of information about these groups of objects. One purpose of this article is to explore connections between these two answers regarding the utility of categories.The idea that categories serve certain functions for the organism raises the possibility that some categories fulfill these functions better than others. The clearest evidence that certain natural categories are "better" than others stems from the work on "basic-level" categories (Mervis & Rosch, 1981;Rosch, Mervis, Gray, Johnson, & Boyes-Braem, 1976). A basic-level category is one that is preferred by people over its superordinate and subordinate categories. For example, when shown a picture of a particular object, most people will identify it as a chair rather than as furniture or a kitchen chair. From this and other evidence, chair is considered to be a basic-level category for most people.A variety of empirical phenomena demonstrates the superiority of basic-level categories (Mervis & Rosch, 1981). As suggested above, when people are shown an object, they tend to name it at the basic level (Rosch et al, 1976). In recognition tasks, people recognize basic-level objects faster than either subordinates or superordinates (Jolicoeur, Gluck, & Kosslyn, 1984;Rosch et al., 1976). Basic-level names generally have arisen earlier in the development of languages (Berlin, Breedlove, & Raven, 1973), and basic categories are used earlier in the naming and other behavior of young children (Anglin, 1977;Brown, Many people have provided us with suggestions, criticisms, and comments on this work over the last 6 years. However, we must especially thank Pat Langley and Doug Fisher for their early and continuing encouragement. Doug Fisher's own research has contributed to our understanding of many of the issues discussed here. We also thank three anonymous reviewers for their in...
