OBJECT REPRESENTATION IN THE BOTTLE-NOSED-DOLPHIN (TURSIOPS-TRUNCATUS) - INTEGRATION OF VISUAL AND ECHOIC INFORMATION

A dolphin performed a 3-alternative matching-to-sample task in differe nt modality conditions (visua/echoic, both vision and echolocation; vi sual, vision only; echoic, echolocation only). In Experiment 1, traini ng occurred in the dual-modality (visual/echoic) condition. Choice acc uracy in tests of all conditions was above chance without further trai ning. In Experiment 2, unfamiliar objects with complementary similarit y relations in vision and echolocation were presented in single-modali ty conditions until accuracy was about 70%. When tested in the visual/ echoic condition, accuracy immediately rose (95%), suggesting integrat ion across modalities. In Experiment 3, conditions varied between pres entation of sample and alternatives. The dolphin successfully matched familiar objects in the cross-modal conditions. These data suggest tha t the dolphin has an object-based representational system.