Categorization by People and Pigeons: The Twenty-second Bartlett Memorial Lecture

In one set of experiments, the experience of categorizing sets of variable exemplars of two categories enhanced subjects' ability to discriminate between two new instances of one of these categories. In a second set, subjects that had categorized two sets of exemplars responded more accurately to the hitherto unseen prototype than to a new exemplar close to the category boundary; but in some cases they responded even more accurately to a new exemplar, even further from the category boundary, than to the prototype. In both sets of experiments, people and pigeons behaved in similar ways. The implication is that at least in some situations human behaviour is controlled by a relatively simple set of associative processes, whose operations have been elucidated by conditioning experiments in animals.