Our senses often work together, creating connections between seemingly unrelated experiences. For instance, the way something sounds can influence how we perceive its shape. This interconnectedness allows us to build a richer understanding of the world around us.
What is the Bouba Kiki Effect?
The Bouba Kiki effect describes a tendency for people to consistently associate certain speech sounds with particular visual shapes. This phenomenon was first explored in the 1920s by psychologist Wolfgang Köhler, who showed participants two abstract shapes: one rounded and blob-like, and the other sharp and spiky. He then asked them to assign one of two made-up words, “takete” or “malumba,” to each shape. The results showed a strong preference for linking “takete” with the spiky shape and “malumba” with the rounded one.
In 2001, V. S. Ramachandran and Edward Hubbard replicated Köhler’s experiment using the non-words “bouba” and “kiki”. They presented participants with a rounded, curvy shape and a jagged, spiky shape. When asked to assign the words, 95% to 98% of participants chose the curvy shape as “bouba” and the jagged one as “kiki”. For example, “bouba” tends to fit a soft, round cloud, while “kiki” aligns with a sharp, zigzagging lightning bolt.
Why Sounds and Shapes Connect
This consistent association between sounds and shapes stems from the physical characteristics of speech production and perception. When we pronounce “bouba,” our lips tend to form a rounded shape, and the sound itself often involves lower frequencies. This rounded mouth posture and the smooth, continuous flow of air intuitively align with the visual perception of a soft, rounded object.
Conversely, producing the “kiki” sound involves sharper, more angular mouth movements, like those made when saying the “k” sound, and higher frequencies. The abruptness of the “k” sound and the quick, precise tongue movements mirror the visual qualities of a spiky or jagged shape. These connections between mouth movements and acoustic properties create a natural, unconscious link to visual forms.
A Universal Connection
The Bouba Kiki effect has shown remarkable universality, not limited to English speakers or specific cultures. Studies confirm this association across various languages, including among Tamil speakers in India, and in children as young as 2.5 years old. A large-scale online experiment involving speakers of 25 languages from nine language families and ten writing systems further confirmed the effect across diverse groups.
While some variations exist, such as slightly lower rates of association in certain languages like Mandarin Chinese, Turkish, Romanian, and Albanian, the general tendency remains. This widespread consistency suggests that the Bouba Kiki effect is not simply a learned linguistic behavior but rather a more fundamental cognitive process. Beyond visual shapes, the effect can also extend to other senses, such as tactile sensations, where certain sounds might be associated with smooth or rough textures.
How This Effect Matters
The Bouba Kiki effect has several interesting implications across different fields. In the evolution of language, it suggests that the formation of words might not have been entirely arbitrary. Instead, some of the earliest words could have been influenced by sound symbolism, where the sounds themselves mimicked aspects of the objects or concepts they represented. This means that the perceived “roundness” of words like “balloon” might not be a mere coincidence.
In marketing and branding, understanding this effect can be a powerful tool. Companies can strategically choose product names or design logos that evoke specific feelings or characteristics. For example, a brand aiming for a friendly, adaptable, or smooth image might opt for “bouba”-like names and rounded designs, while a brand seeking to convey precision, efficiency, or modernity might lean towards “kiki”-like names and angular visuals. This deliberate use of sound symbolism can influence consumer perception and brand identity.
Recent research has also explored the Bouba Kiki effect in artificial intelligence models. Studies show that vision-and-language models, such as CLIP and Stable Diffusion, exhibit sound-shape associations when generating images from pseudowords. This suggests AI models, much like humans, can form non-arbitrary connections between sounds and visual properties, advancing understanding of both human cognition and AI.