Experimental procedures involved training a tortoise to approach a sound source for a food reward, followed by a test where the tortoise had to choose between two flapping doors with different sized discs based on high or low-pitch sounds.
Two Testudo hermanni tortoises.
Newswise — An international research team from Queen Mary University of London, UK, and the Rovereto Civic Museum Foundation, Italy, has made a groundbreaking discovery concerning reptiles' ability to synchronize visual and auditory information.
Published in Biology Letters by the Royal Society, their research findings reveal that reptiles possess a fascinating capacity to spontaneously connect distinct sensory modalities, specifically vision and hearing. The study focused on tortoises, which exhibited a remarkable inclination to associate low-frequency sounds with large shapes and high-pitched sounds with small shapes, even without any prior training. This revelation sheds light on how reptilian brains are naturally equipped to anticipate visuo-acoustic correspondences commonly encountered in their natural environment.
While previous investigations have identified crossmodal associations between sensory modalities in mammalian species such as humans, chimpanzees, and dogs, it remained uncertain whether these associations extended to other vertebrate animals, particularly reptiles. To address this knowledge gap, Dr. Maria Loconsole, formerly affiliated with Queen Mary University of London and now associated with the University of Padova, along with Dr. Elisabetta Versace, also from Queen Mary University of London, spearheaded a study with the primary objective of exploring and elucidating the presence of these crossmodal associations in reptilian species.
To uncover the spontaneous preferences of land tortoises (Testudo hermanni) in matching acoustic pitch (high vs. low tone) with visual size (small vs. large disk), the research team conducted a choice task. Initially, the tortoises were trained to follow sounds leading them to a food reward. Subsequently, they underwent tests to determine their preferences for high and low pitch sounds, each associated with either small or large shapes. The aim of this experiment was to reveal the innate tendencies of the tortoises in forming associations between auditory and visual stimuli without explicit training.
Dr. Maria Loconsole expressed astonishment at the remarkable findings of the study. The tortoises consistently exhibited a clear preference for small disks when exposed to high-pitched sounds, and conversely, they chose large disks when confronted with low-pitched sounds. These intriguing results shed light on how natural environmental patterns, such as the correspondence between size and pitch, influence and shape the cognitive abilities of animals. The research offers valuable insights into the interplay between sensory modalities and cognition in reptilian species, contributing to a broader understanding of animal behavior and perception.
The research findings strongly suggest that crossmodal associations are not limited to specific species but are widespread across various animal groups, implying that they might serve as an organizing principle of the vertebrate brain. Dr. Elisabetta Versace, Senior Lecturer at Queen Mary University of London, points out that this phenomenon could have evolved independently in mammals, birds, and reptiles, or it might be a shared mechanism inherited from a common ancestor. To gain a deeper understanding of the brain's organization and behavioral evolution, it becomes crucial to extend research efforts to encompass a diverse range of species. By studying a wide array of animals, we can uncover general principles governing brain functioning and behavior, providing valuable insights into the intricacies of evolution and cognitive processes across the animal kingdom.
Gionata Stancher, the head of Zoology at the Rovereto Civic Museum Foundation, expresses his delight in collaborating with Queen Mary University of London. The collaboration highlights the significance of preserving the sanctuary, not only for the protection of land tortoises but also for its invaluable contribution to advancing knowledge on animal behavior and cognition. This research underscores the vital role that sanctuaries and protected environments play in unraveling the mysteries of the animal kingdom, ultimately fostering a deeper appreciation and understanding of the natural world and its diverse inhabitants.
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Credit: M. Loconsole et. al./Biology letters
Caption: Experimental procedures involved training a tortoise to approach a sound source for a food reward, followed by a test where the tortoise had to choose between two flapping doors with different sized discs based on high or low-pitch sounds.
Credit: Francesco Rossi
Caption: Two Testudo hermanni tortoises.
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