Picture–object recognition in the tortoise Chelonoidis carbonaria
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To recognize that a picture is a representation of a real-life object is a cognitively demanding task. It requires an organism to mentally represent the concrete object (the picture) and abstract its relation to the item that it represents. This form of representational insight has been shown in a small number of mammal and bird species. However, it has not previously been studied in reptiles. This study examined picture–object recognition in the red-footed tortoise (Chelonoidis carbonaria). In Experiment 1, five red-footed tortoises were trained to distinguish between food and non-food objects using a two-alternative forced choice procedure. After reaching criterion, they were presented with test trials in which the real objects were replaced with color photographs of those objects. There was no difference in performance between training and test trials, suggesting that the tortoises did see some correspondence between the real object and its photographic representation. Experiment 2 examined the nature of this correspondence by presenting the tortoises with a choice between the real food object and a photograph of it. The findings revealed that the tortoises confused the photograph with the real-life object. This suggests that they process real items and photographic representations of these items in the same way and, in this context, do not exhibit representational insight.
KeywordsPicture–object recognition Tortoise Turtle Reptile Visual perception
The authors would like to thank the cold-blooded cognition group at the University of Vienna and the University of Lincoln for their helpful comments. We particularly thank Karin Kuenstner for help in running part of the experiment. We are also indebted to Wolfgang Berger for making the setup and Michael Pollirer for providing the experimental arena. This work was supported by funding from the Austrian Science Fund (to L.H.) contract number P19574.
Conflict of interest
The authors declare that they have no conflict of interest.
The experiments comply with the current laws of Austria.
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