Conceptual Categorization

Abstract

Abstract For the past 15 years my research has concentrated on how infants form their first concepts. Because forming a concept usually involves forming a category, I often call concepts conceptual categories. This is a cumbersome expression, but I believe it is important to distinguish two different kinds of mental structures: co ceptual and perceptual categories. Some researchers find this distinction unnecessary, but the view of categorization as a uniform process faces difficulty in accounting for many facets of mental life. As the chapters in this book testify, categorization itself is ubiquitous in mental functioning. But even though some basis of similarity is involved in all kinds of categories, content differs radically. We can categorize on the basis of single or multiple dimensions (square, loud, red), the behavior of things (animate and inanimate), abstract meaning (good and evil), and even ad hoc bases (things to take if the house catches on fire; Barsalou, 1973). This range of content from perceptual dimensions to abstract ideas, combined with the fact that some categorization is deliberate and requires effortful retrieval, whereas other categorization occurs automatically without effort, makes it highly unlikely that all categorization rests on a single process. I refer the reader to a summary of both psychological and neurological evidence showing that adults engage in more than one kind of categorization (Smith, Patalano, & Jonides, 1998). Later in this chapter I summarize some developmental evidence that also militates against the view that all categorization is of the same form. The most obvious example is that we all form perceptual categories as a natural part of perceiving, but on deliberate categorization tasks both children and adults do many different things, such as categorize on the basis of overall appearance, single dimensions, or meaning. This range of variation in the kind of processing that is taking place means that whenever one talks about categorization it is crucial to specify the kind of categories one has in mind. The widespread failure to do so accounts for many of the controversies in this area of research.