A sound is usually something heard rather than seen, yet the human brain often links particular sounds with specific visual forms. A rounded shape may seem to suit a soft-sounding word, while a sharp shape feels more appropriate for a sound with crisp edges.
New research suggests that domestic dogs may make similar connections, offering another clue about how animals process information through different senses.
<h3>A Curious Connection Between Sound and Sight</h3>
The phenomenon is known as the Bouba–Kiki effect. In human studies, people commonly associate the invented word “Bouba” with rounded shapes and “Kiki” with angular ones. The words have no fixed meanings, so the pattern suggests that certain sound qualities may naturally correspond with visual features.
Researchers wanted to know whether this association also appears in dogs. The study, published in Proceedings of the Royal Society B: Biological Sciences in 2026, examined how pet dogs responded when they heard the two made-up sounds while looking at different shapes. The research involved 70 domestic dogs and was led by Eleonora Biffi and colleagues. Its central question was whether dogs could show a consistent preference for particular shapes depending on the sound playing nearby.
<h3>How the Experiments Worked</h3>
The researchers conducted two experiments. In the first, 51 dogs participated alongside their owners. Each dog encountered two screens displaying black shapes: one with rounded edges and another with sharp, pointed angles. Speakers played either “Bouba” or “Kiki” repeatedly while the dogs faced the screens. During the initial part of each trial, owners kept their dogs positioned toward the displays. A camera recorded the animals' behavior, allowing researchers to analyze which screen attracted their attention.
After the viewing period, the dogs could move freely and inspect the area. This gave the team another way to examine their responses beyond simply measuring where they looked. The second experiment included 19 additional dogs. This time, owners wore headphones playing music so they could not hear the sounds used during the test. The adjustment helped address a potential source of bias: owners might unintentionally influence their pets through movements or other subtle signals when they know which sound is playing.
<h3>What the Dogs' Responses Revealed</h3>
Across both experiments, dogs spent significantly more time looking at rounded shapes when “Bouba” was played and at pointed shapes when they heard “Kiki.” The pattern suggests that the animals associated the sound qualities with different visual forms.
During the free-exploration period in the first experiment, dogs also spent more time investigating the pointed shape while “Kiki” played. However, the second experiment did not produce the same preference during free exploration. That difference is important. It suggests that the association was clearer in the dogs' looking behavior than in their later exploration. The findings should therefore be interpreted carefully rather than treated as proof that dogs understand sounds in exactly the same way humans do.
<h3>What This Means for Animal Cognition</h3>
People often assume that interpreting sounds symbolically requires advanced language skills. Yet the Bouba–Kiki effect raises the possibility that some links between sound and appearance may emerge from more basic features of perception. For example, a sound with abrupt changes may feel compatible with an angular outline, while a smooth, flowing sound may seem to fit a curved form. Researchers are still working to understand why such connections occur and how widely they are shared across species.
The dog study contributes to this wider question by showing that an animal does not necessarily need spoken language to display a relationship between auditory and visual information. However, the experiments cannot establish precisely what the dogs were thinking. Their behavior could reflect perceptual preferences or learned associations rather than an understanding of words as symbols.
The study offers an intriguing look at how dogs may connect what they hear with what they see. Their responses to “Bouba” and “Kiki” suggest that sound–shape associations are not exclusive to humans, although the precise mental processes behind the behavior remain uncertain.
Rather than proving that dogs interpret language as people do, the findings highlight a broader possibility: different senses may work together in ways that scientists are only beginning to understand. Further research will help clarify how widespread these connections are and what they reveal about animal perception.
