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Crossmodal Pitch-Luminance Association in Tortoises
Maria Loconsole1, Beatrice Malaman1, Gionata Stancher2
1Department of General Psychology, University of Padova, Padova, Italy.
Annals of the New York Academy of Sciences
|September 16, 2025
Summary
Hermann's tortoises spontaneously associate higher-pitched sounds with white and lower-pitched sounds with black, similar to humans and chimpanzees. This crossmodal association suggests shared perceptual strategies across diverse species.
Area of Science:
- Cognitive Science
- Comparative Psychology
- Neuroscience
Background:
- Crossmodal associations, spontaneous links between sensory modalities, are common in humans and other animals.
- Previous research indicates pitch-luminance associations in humans and chimpanzees, but not in baboons or chickens.
- The evolutionary origins of crossmodal associations remain debated, with possibilities including shared cognitive strategies or learned behaviors.
Purpose of the Study:
- To investigate pitch-luminance associations in a nonvocal reptile, the Hermann's tortoise (Testudo hermanni).
- To determine if tortoises exhibit spontaneous crossmodal associations similar to those observed in primates.
Main Methods:
- A spontaneous food-searching task was designed for tortoises.
- Tortoises were exposed to either higher-pitched (700 Hz) or lower-pitched (450 Hz) sounds.
- The animals then chose to search for food behind either a light (white) or dark (black) colored wall.
Main Results:
- Tortoises consistently associated higher-pitched sounds with the white wall.
- Tortoises consistently associated lower-pitched sounds with the black wall.
- These findings mirror the pitch-luminance associations observed in humans and chimpanzees.
Conclusions:
- The study provides novel evidence of pitch-luminance association in Hermann's tortoises.
- This suggests that phylogenetically distant species may share similar perceptual organization or statistical learning mechanisms.
- The findings raise questions about whether these crossmodal associations are due to homology or convergent evolution.
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