[Generalization by the relative sign of "top" in bottlenose dolphins]

Bottle-nosed dolphins demonstrated the ability to distinguish the top position of the objects in the process of learning. They always chose the top object from the three identical things under conditions of permanent location changing of this stimulus triplet on one of the sides of the water enclosure. Specialization of the reflex was tested under conditions of the stimulus triplet administration at the background of different situational changes in surroundings, including the changes in location of external reference points. The animals retained the adequate reaction also after a sudden substitution of the initial stimulus objects for others which were considerably different from the initial stimuli in the shape, material, size etc. When the natural stimuli (three fishes) were presented of the number of the stimuli was substituted from 2 for 5, nevertheless, the dolphins chose the top stimulus. The findings testify to the capability of dolphins for generalization by the relative sign "top position".