1956/Bruner/2

This process of categorizing involves ... an act of invention. This hodgepodge of objects is comprised in the category "chairs," that assortment of diverse numbers is all grouped together as "powers of 2," these structures are "houses" but those others are "garages." What is unique about categories of this kind is that once they are mastered they can be used without further learning. We need not learn de novo that the stimulus configuration before us is another house. If we have learned the class "house" as a concept, new exemplars can readily be recognized. The category becomes a tool for further use. The learning and utilization of categories represents one of the most elementary and general forms of cognition by which man adjusts to his environment. It was in this belief that the research reported in this volume was undertaken. For it is with the categorizing process and its many ramifications that this book is principally concerned.