- Unpublished master's thesis, University of Hawaii, Honolulu.
Judgments of Similarity of Rotated and Unrotated Objects by a Bottlenosed Dolphin (Tursiops truncatus) - Matthias Hoffmann-Kuhnt
University of Hawaii, Kewalo Basin Marine Mammal Lboratory, 1129 Ala Moana Blvd., Honolulu, HI, USA, 96814 -
- (C) 1994 University of Regensburg, Germany
In this study a male bottlenosed dolphin’s ability to judge the similarity of rotated and unrotated figures in a visual two-alternative-matching-to-sample task was examined. The dolphin was shown capable of recognizing between two- and three-dimensional stimuli which differed only in shape, but he was not able to distinguish between mirror image stimuli. In the first experiment, the dolphin successfully learned o use three display boxes, a stationing device, and response paddles to indicate his choice in the matching task. Experiments 2 and 3 revealed a profound difficulty to recognize mirror image stimuli in the matching task using several pairs of novel asymmetrical objects. However, limited evidence for discriminating between mirror images was revealed with two of seven pairs. Experiments 4 and 5 identified two key elements, rotation and feature displacement, which are important components for being able to successfully recognize mirror images, and tested the dolphin’s sensitivity to these features. The dolphin was shown capable of discriminating between different orientations of the same stimuli, if the disparity was larger than 15&Mac176;, but he showed difficulties in differentiating between objects consisting of the same features arranged differently. The final experiment tested the dolphin’s ability to discriminate asymmetrical rotated mirror images. Although he was not able to significantly match these stimuli correctly to the sample, his performance accuracy indicated that orientation of the stimuli was not the sole basis for his responses. The results of all experiments suggest that the dolphin had profound difficulties with the discrimination of mirror image stimuli and that this may in part be due to the nature of the matching task in which the dolphin was tested.
Hoffmann-Kuhnt, M. (1994). Judgments of Similarity of Rotated and Unrotated Objects by a Bottlenosed Dolphin (Tursiops truncatus). Unpublished master's thesis, Univeristy of Regensburg, Germany.
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