Domestic dogs may share the human tendency to link specific sounds with rounded and pointed shapes, according to a 2026 study published in Proceedings of the Royal Society B: Biological Sciences. Researchers used AI head-tracking during trials to discover that canines looked significantly more at rounded shapes when hearing Bouba
and explored spiky forms during Kiki
.
Hold up a soft, curving blob and a jagged star to most people anywhere in the world, ask them to name one Bouba
and the other Kiki,
and you will get near-universal agreement. The smooth shape gets the gentle moniker; the sharp edges claim the hard consonant. This psychological phenomenon, first documented in the 1920s, points to a deep cross-cultural link between visual forms and auditory sounds.
Now, behavioral researchers suggest this inclination is not strictly human. Canines appear to follow the same pattern, tying linguistic sounds to visual geometries in a manner similar to people.
University of Parma Experiments and AI Tracking
Eleonora Biffi, an animal behaviorist at the University of Parma, led a team that recruited 70 domestic dogs for a pair of controlled trials. The initial setup placed 51 dogs and their owners into a room equipped with dual screens and speakers positioned on opposite sides. After letting the animals acclimate to the surroundings, owners sat centrally while automated equipment cycled through combinations of human voices uttering either Bouba
or Kiki
alongside rounded and pointed shapes.
GoPro cameras filmed every session. To eliminate human bias in observing animal reactions, the investigators fed these videos into an AI programmed to detect head orientation. This computational approach allowed the team to measure where the canines focused their attention beyond random chance.
Rock Music Isolates Owners to Verify Dog Reactions
To verify whether the pets were simply reacting to subtle physical signals from their human companions, the research team designed a second experiment with 19 different dogs. The physical layout remained identical, but the owners wore headphones playing rock music to block out the audio test entirely.
While study participants in the first group displayed a general bias toward looking at spiky forms overall, that specific tendency vanished once owners were isolated via rock music. Yet, the core correlation between the sounds and the matching shapes held firm. The animals still aligned Bouba
with rounded geometries and Kiki
with angular ones based on their own independent focus.
It could be hypothesized that the dogs were influenced by the owners’ unintentional cues.
Study authors, Proceedings of the Royal Society B: Biological Sciences
Investigators also proposed an anatomical rationale for the initial spiky-shape bias observed in the first trial. Ancient canids and wolves possess facial structures defined by angular, ‘spiky’ features, offering a distinct contrast to the round facial morphology common to human infants that might cultivate an opposing visual preference.
Broader Implications for Human-Animal Communication
Researchers caution that definitive declarations remain premature. Additional work is necessary to fully map how domestic animals process sound symbolism and link vocalizations with physical objects. Still, these findings offer a foundational baseline for investigating why dogs grasp human language with such agility and how they became human companions in the first place.