The bouba/kiki effect is one of the odder psychological phenomena. For some reason, when presented with two random shapes (one angular and another rounded), and two nonsense words (“kiki” and “bouba”), people tend to associate bouba with the lobed figure and kiki with the spiky one. First discovered in the 1920s, this particular idiosyncrasy of the human mind is a strong indication that we associate certain sounds with certain shapes, which has important implications for the evolution of language.
It’s also proved to be strikingly widespread. Cultures from around the globe speaking different languages can “correctly” identify bouba and kiki (including those with no written language). In fact, when people who have been blind since birth are presented with 3D representations of the figures, they too get it right. Now, according to a new study published in the Proceedings of the Royal Society B: Biological Sciences, the bouba/kiki effect may even extend to dogs.
To investigate the possibility of a canine bouba/kiki effect, a team of animal behaviorists recruited 51 dogs and their owners. They invited the pairs into a room with two screens on either wall, one of which displayed the rounded bouba figure and the other displaying the sharp kiki figure. After the dogs settled in, the team played a human voice saying the words “bouba” and “kiki” over a set of speakers while a camera recorded their reactions. In an effort to avoid the owners accidentally sending subtle cues to their canines, the researchers repeated the experiment with 19 dogs whose owners were wearing headphones.
Read more: “Why Do Some People Look Like Their Dogs?”
The team used artificial intelligence to track where and for how long the canines looked during the experiment. They found that the dogs tended to look longer at the rounded shape when the word “bouba” was played and longer at the angular shape more often when the word “kiki” was played. (Weird, right?)
It’s not the first time the bouba/kiki effect has been found in animals, however. A study published earlier this year found that baby chickens, freshly hatched from their eggs, made the association. The chicks, however, showed an overall bias toward rounded shapes, and the researchers discovered something similar in this study.
Overall, dogs in the first setup showed a general bias toward gazing at the kiki shape. But this bias wasn’t present in the second setup, when the owners’ ears were covered. According to the team, this strange discrepancy probably can’t be chalked up to subtle cues. “It could be hypothesized that the dogs were influenced by the owners’ unintentional cues,” they write. “However, since humans typically show a stronger preference for rounded or curved shapes rather than spiky ones, this is unlikely.”
Instead, the bias toward spiky shapes in the larger, first experimental group may have something to do with a sensory bias in dogs. “In the case of dogs, animals’ facial configuration, especially when considering ancient dogs and wolves, is characterized by more angular, ‘spiky’ features, which contrasts with the round facial morphology typical of human infants and could plausibly contribute to an opposite bias,” they wrote.
In other words, dog morphology is relatively spiky so they prefer spiky shapes, whereas our faces are round so we prefer rounder shapes.
Of course, the researchers stress that all of this will take more study with larger sample sizes to suss out. But either way, welcome to the bouba/kiki club, canines! 
Enjoying Nautilus? Subscribe to our free newsletter.
Lead Image: Mary Swift / Shutterstock