Generalization of a visual matching-to-sample rule was shown for the first time in a bottlenosed dolphin (Tursiops truncatus), normally considered an auditory specialist. The visual items used were all real-world objects. Some objects had acoustic names in an artificial acoustic language taught to the dolphin named Phoenix. Other objects were unnamed but familiar to Phoenix, and still others were objects entirely new to her experience. In Experiment 1 and 2, we demonstrated Phoenix's ability to match these objects, from among two alternative comparison objects, at levels of 87% correct responses or better, after 0-s delay. In Experiment 3, Phoenix's matches of familiar and of new objects were better than 94% correct through to delays of 30 s and were 73% correct after a delay of 80 s. In Experiment 4, performance was nearly equivalent for statically displayed and dynamically displayed sample objects. Over the four experiments, Phoenix matched 16 of 18 objects successfully on the first trial that they appeared as samples. From these and other recent Findings, it appears that bottlenosed dolphins are capable of carrying out both visualand auditory-based complex cognitive tasks approximately equally well, a finding at variance with earlier notions of sensory modality limitations in cognitive performance of animals.Animals may interact with their world through a variety of sensory' modes, yel il often appears that many cognitive capacities are modality limited. The concept of modality limitation, often called modality specificity, holds that advanced cognitive skills, or even simple ones, may be largely restricted to the dominant sensory modality of the species. For example, monkeys may solve visual hut not auditory tasks easily (D'Amato, 1973;D'Amato & Salmon, 1982;Thompson, 1981), whereas the reverse may hold for dolphins (Herman, 1980). These modality-related differences are not traceable to raw sensory limitations. Monkeys have welldeveloped hearing abilities (Fobes & King, 1982) and dolphins have a highly evolved visual system (Dawson, 1980; Herman, Peacock, Yunker, & Madsen, 1975).Recent work has begun to dispel or reshape some of the notions about modality specificity. D'Amato and Colombo (1985) and Colombo and D'Amato (1986) reported on the ability of capuchin monkeys (Cebiis apella) to learn auditory delayed matching-to-sample (DMTS) tasks, and similar find-

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In 2001, Xitco et al. (Anim Cogn 4:115-123) described spontaneous behaviors in two bottlenose dolphins (Tursiops truncatus) that resembled pointing and gaze alternation. The dolphins' spontaneous behavior was influenced by the presence of a potential receiver, and the distance between the dolphin and the receiver. The present study adapted the technique of Call and Tomasello [(1994) J Comp Psychol 108:307-317], used with orangutans to test the effect of the receiver's orientation on pointing in these same dolphins. The dolphins directed more points and monitoring behavior at receivers whose orientation was consistent with attending to the dolphins. The results demonstrated that the dolphins' pointing and monitoring behavior, like that of apes and infants, was linked to the attentional behavior of the receiver.

The nature and extent of dolphin intelligence has long intrigued humans. Unequivocal answers to the question "how intelligent are dolphins?" have proven evasive due to both the existing myriad views of intelligence and the ambiguity of much spontaneous dolphin behavior. In this paper, we focus on one aspect of intelligence, namely the ability to plan one's behavior in a meaningful way. The generalized ability to create novel and appropriate behavioral plans when confronted with new problems has obvious evolutionary advantages, but has been found in relatively few species. The studies reported in this paper demonstrate planning behaviors in bottlenose dolphins (Tursiops truncatus) in conditions quite different from those that occur during dolphin foraging and mating (two areas in which wild dolphins may engage in planning). The dolphins' ability to plan their behaviors in these novel contexts provides additional evidence that generalized planning ability is not unique to humans, and demonstrate that human-like language is not required for generalized planning skills. These findings also suggest that in addition to species niche specific cognitive abilities, generalized cognitive abilities may play an important role in the evolutionary success of some species.

Dolphins exhibit both action-level imitation (ALI) and program-level imitation (PLI). Dolphins may use ALI primarily for social cohesion, whereas PLI seems more likely to occur in goal-directed, problem-solving contexts. Both PLI and insightful problem solving require a recognition of the functional relations between actions and outcomes. Insightful problem solving, however, involves the creation of a program in the absence of a model, and therefore requires a higher order appreciation and application of the relations between actions and outcomes.