The neurobiology of categorization

Categorization is the act of responding differently to objects or events in separate classes or categories. It is a vitally important skill that allows us to approach friends and escape foes, to find food, and avoid toxins. The scientific study of categorization has a long history. For most of this time, the focus was on the cognitive processes that mediate categorization. Within the past decade, however, considerable attention has shifted to the study of the neural basis of categorization. This chapter reviews that work. It begins with a brief overview of the basal ganglia, which are a collection of subcortical nuclei that are especially important in categorization. It then focuses on initial category learning and considers the neural basis of automatic categorization judgements.