Related Experiment Video
Updated: Jul 16, 2026
12:30
Testing Visual Sensitivity to the Speed and Direction of Motion in Lizards
Published on: December 14, 2006
Reversed sound-shape association in tortoises (Testudo marginata)
Giovanna Marliani1, Gionata Stancher2, Maria Loconsole3
1Department of General Psychology, University of Padova, Padova, Italy.
Animal Cognition
|July 14, 2026
Summary
Tortoises exhibit a reversed Bouba-Kiki effect, exploring shapes opposite to sound associations seen in humans. This suggests crossmodal cognition may differ across species or be influenced by task structure.
Area of Science:
- Cognitive Science
- Comparative Psychology
- Neuroscience
Background:
- Crossmodal correspondences are spontaneous sensory links observed across species.
- The Bouba-Kiki effect, linking sound symbolism to shape, is documented in humans, infants, and some animals.
- Reptiles' crossmodal perception remains largely unexplored.
Purpose of the Study:
- To investigate the Bouba-Kiki effect in the marginated tortoise (Testudo marginata).
- To determine if tortoises exhibit sound-shape correspondences similar to humans and birds.
- To explore the role of task structure in crossmodal perception.
Main Methods:
- A free-exploration task was designed for 10 marginated tortoises.
- Tortoises were exposed to "Bouba" and "Kiki" sounds paired with round and spiky 3D objects.
- Exploration time for each object during different sound playbacks was recorded.
Main Results:
- Tortoises displayed a reversed Bouba-Kiki effect compared to humans.
- They explored the round object longer during "Kiki" sound playback.
- They explored the spiky object longer during "Bouba" sound playback.
Conclusions:
- The reversed sound-shape mapping in tortoises challenges universal assumptions of crossmodal cognition.
- The findings may indicate an interaction between innate sound-shape correspondences and task-specific exploratory behaviors.
- Alternatively, tortoises might possess fundamentally different perceptual organization principles for crossmodal associations.
