Sensory integration in the bottlenosed dolphin: immediate recognition of complex shapes across the senses of echolocation and vision.

In matching-to-sample tests, a bottlenosed dolphin (Tursiops truncatus) was found capable of immediately recognizing a variety of complexly shaped objects both within the senses of vision or echolocation and, also, across these two senses. The immediacy of recognition indicated that shape information registers directly in the dolphin's perception of objects through either vision or echolocation, and that these percepts are readily shared or integrated across the senses. Accuracy of intersensory recognition was nearly errorless regardless of whether the sample objects were presented to the echolocation sense and the alternatives to the visual sense (E-V matching) or the reverse, with samples presented to the visual sense and alternatives to the echolocation sense (V-E matching). Furthermore, during V-E matching, the dolphin was equally facile at recognition whether the sample objects exposed to vision were "live," presented in air in the real world, or were images displayed on a television screen placed behind an underwater window. Overall, the results suggested that what a dolphin "sees" through echolocation is functionally similar to what it sees through vision.