Concept formation in American black bears, Ursus americanus

Despite their large relative brain size, bears have been neglected in studies of comparative cognition in comparison to their fellow carnivores, the social canines and pinnipeds. Here, three captive adult American black bears were presented with a series of natural concept discrimination tasks on a touchscreen computer, in which the discriminations varied in degree of abstraction. The more abstract discriminations could not be performed by attending to perceptual features of the stimuli alone. For instance, at the most abstract level, the bears were required to select images of animals rather than nonanimals, and exemplars within both categories were perceptually diverse. At least one bear performed at above-chance levels with transfer to novel images at each level of abstraction. The bear that began testing with the most abstract problems showed the best transfer on more abstract discriminations, suggesting that the usual practice of overtraining animals on perceptual discriminations may hinder their ability to acquire concepts at more abstract levels. The bears' performance suggests that a generalized diet may be more critical than group living with regard to the evolution of complex cognition in carnivores.

► This is the first demonstration of concept formation in bears, using a touchscreen computer.
► Bears formed natural concepts at concrete, intermediate and abstract levels.
► Black bears, a nonsocial species, showed transfer comparable to that of great apes tested previously.
► Presenting more abstract discriminations first, contrary to standard procedures, appeared to facilitate performance.