Categorization and Conceptual Behavior in Nonhuman Primates

Animals often behave adaptively in response to a between exemplars of a class. Thus, level 4 is novel stimulus because the stimulus resembles more complex than open-ended classification, others for which the appropriate response is al- the latter being related to the use of perceptual ready known. Such an adaptation expresses an dimensions of stimuli. [See Schrier et al. (1984) ability to categorize. In effect, in the absence of for an example in macaques, D'Amato and Van categorization, each object or event would be Sant (1988) for an example in cebus monkeys, perceived as unique, and generalizations would and Vauclair and Fagot (1996) for an example in be impossible. Therefore it is not surprising to Guinea baboons.] Level 5 of Herrnstein's cate-find categorizing abilities in various animal spe- gorization is attained when a subject is able to cies, although most of the empirical evidence use abstract relations not only between objects concerns birds (mainly pigeons) and primates. but also between concepts, such as in conceptual Since categorization is a fundamental aspect of matching or in conceptual identity (for example, information processing, its study is crucial for the mastery of a "sameness " relation). The evi-increasing our understanding of animals ' cogni- dence for capacities to perform the first three tive abilities. levels of categorization is abundant for severa