BOTTLENOSE DOLPHINS CAN GENERALIZE RULES and DEVELOP ABSTRACT CONCEPTS

Abstract: Generalization of a rule is demonstrated if the rule governs a class of problem, and the subject, after successful experience with a limited number of problems, can apply the governing rule to new problems within that class. We show that the bottlenose dolphin ( Tursiops truncatus ) is capable of such generalization for classes of problems requiting the matching of one of two alternative stimuli to a "sample" stimulus to which the animal had been previously exposed, regardless of the sensory domain used: vision, passive listening, or active echolocation. We also show this generalization capability in a related class of problem requiring a judgment of whether a single "probe" stimulus is the same as, or different from, a stimulus or stimuli previously presented. Further, one dolphin was shown capable of developing a true abstract concept of same/different through its ability to categorize pairs of simultaneously presented objects as identical or not. The suggestion that such generalization ability of dolphins may be in question because of so-called exclusion effects is shown to be not tenable when the whole body of available data is considered.