ABSTRACT
What kind of categories do human concepts represent? Classical categories are defined by necessary and sufficient criteria that determine whether an object is in a category or not in it. A popular contemporary view is that concepts correspond instead to prototype categories. Prototype categories lack necessary and sufficient conditions; their members need not be absolutely “in” or “out of” the category but can be members to greater or lesser degrees; their members display family resemblances in a number of characteristic properties rather than uniformly sharing a few defining properties; and they are organized around “prototypical” exemplars. This distinction raises several questions. Is one type of category psychologically real, the other an artifact (of formal schooling, or of the experimental methodologies used to study them)? If both are psychologically real, do they serve different functions in cognition? Are they processed by the same kind of computational architecture? And do they correspond to fundamentally different kinds of things in the world? We suggest that some answers to these questions can be found in an unusual place: the English past tense system.
