Rahul Somvanshi
Pick any two words: “bouba” and “kiki.” Now pick a rounded, cloud-like shape and a spiky, jagged one. Nearly every human tested in 97 years of cognitive psychology research since Wolfgang Köhler’s original 1929 experiment will match “bouba” to the round shape and “kiki” to the sharp one—without ever being told to. The effect is so consistent across cultures and languages that it has been used as evidence that human language is not purely arbitrary. Now a peer-reviewed study published in *Proceedings of the Royal Society B* in mid-October 2026 suggests that domestic dogs do something similar.
The study was led by Eleonora Biffi at the University of Parma, in collaboration with researchers from the University of Padua, the University of Haifa, and Jönköping University. Using automated speaker-screen apparatuses—specifically designed to minimize handler cueing—dogs were exposed to the spoken words “bouba” and “kiki” paired with either a rounded or a spiky visual shape. Across 51 dogs in the first trial, animals showed a tendency to look toward the shape that matched the word’s acoustic character. A follow-up trial with 19 additional dogs—whose owners wore headphones to reduce social cues—found the effect weakened, suggesting owner behavior may play a partial role. The researchers call for further work before drawing strong conclusions.
If you train or live with a dog, this research raises interesting questions about how dogs process the acoustic texture of your voice alongside physical information. The findings are preliminary, and their practical implications for training require further study—but they suggest that sound and shape may be connected in canine perception in ways researchers are only beginning to explore.
Beyond Words: How Sound Shapes Canine Perception
The effect in dogs was observed when rounded, slower spoken sounds were paired with smooth geometric figures, and sharper spoken sounds with spiky angular ones. The researchers note this is consistent with the idea that cross-modal sensory mapping—linking sound character to visual character—may exist in species beyond humans. What remains unclear is the extent to which this reflects genuine innate cross-modal perception versus learned associations from years of living with humans.
The headphone finding is a key caveat: the softening of the effect when owners could not hear the words and react suggests that dogs may partly be following human social cues rather than responding purely to sound-shape congruence. The authors acknowledge this limitation and call for replication under more tightly controlled conditions.
For practical dog training, the study is a reminder that the acoustic texture of vocal cues—their speed, roundness, and abruptness—may communicate information beyond the literal meaning of words. These are not confirmed training rules, but they offer a direction for researchers and attentive handlers to explore.
What is the bouba-kiki effect in dogs? The bouba-kiki effect in dogs, as described in a 2026 *Proceedings of the Royal Society B* study led by Eleonora Biffi at the University of Parma, refers to a tendency for dogs to match rounded visual shapes with softer spoken sounds and angular shapes with sharper sounds—similar to the cross-modal pattern found in humans. The effect was weaker when owners wore headphones, indicating that social cues may be involved. The authors call for further research to establish how robust and generalisable the finding is.
Ancient dog DNA tracking the 30,000-year co-evolutionary arc gives this study its deepest context; previous coverage of canine problem-solving in real emergencies illustrates the practical ceiling of the human-dog communication channel, and the behavioral science underlying major legal decisions about dogs shows the real-world stakes of understanding canine cognition accurately.
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