The Kiki-Bouba effect

Look at the picture above. Which one of the two figures would you call Kiki and which one would you call Bouba? I guess that you’ll say that the left one with jagged shapes is Kiki and the right one with round shapes is Bouba. If so, you are not alone. More than 95% of all people who were asked this question gave the same answer. Moreover, it’s an intercultural phenomenon and it’s also independent of age. The Kiki-Bouba effect prevails even in cultures with no written language and among pre-reader children. Apparently, the relation between the sound of a word and the image it evokes (and the other way round) is to a high extent innate in man. It belongs to man’s nature. On purpose I write “to a high extent”, for, as we saw already, not 100% of all who were asked the question called the jagged-shaped figure Kiki, and for some groups, like autists, and for some cultures the connection is weaker, though it still exists. Nevertheless, we can call the Kiki-Bouba effect a natural phenomenon.
The effect was first discovered in 1929 by the German-American psychologist Wolfgang Köhler, but it has especially been investigated since Vilayanur S. Ramachandran and Edward M. Hubbard repeated Köhler’s experiment in 2001. They introduced also the nonsense words Kiki and Bouba. The effect exists also outside language. For instance, we call some music romantic and other music wild. In music the effect is used for evoking certain feelings or emotions.
Linguists always thought that the relation between the sound of a word and its meaning is arbitrary. The Kiki-Bouba effect shows that as such this view is not right. Of course, when we say “table”, it’s not so that it is inherent to the word that we are talking about a certain piece of furniture with four legs. But the opposite would be that a relationship between language and meaning is completely absent, and that’s not true either. I have shown already that such a relationship exists in my blog “How we think, at least initially”, dated 18 November 2013. The Kiki-Bouba effect is another instance of this relationship.
There are several explanations for the phenomenon. One is quite interesting in view of the relation between language and the way we think: Ideasthesia. Ideasthesia is the term for the neuroscientific phenomenon in which activations of concepts evoke perception-like sensory experiences. Synesthesia is a well-known example. In the case of synesthesia people have sensory responses in reaction to external stimuli. For instance, they see colours, when they hear music. Ideasthesia is broader and involves also the cognitive and semantic aspects of the stimulus: The relationship involved is dependent on the meaning of the stimulus. In the relationship between music and colours, for instance, meaning doesn’t play a part; the phenomenon just happens. In the Kiki-Bouba effect, however, meanings are essential. If you think of a sharp sound you can think of a knife, because a knife is also sharp, albeit in another sense. In the same way there is a relation between Kiki and jagged-shaped and between Bouba and round-shaped. In view of the idea that there is a connection between language and thought this is quite interesting. The Kiki-Bouba effect is an instance of the way we think. It says something about how we are constituted. It’s an example of how in a sense a concept determines the way we look at the world and see reality. Language influences our thinking about the world, although it goes in two directions, of course, for what we see influences also how we speak about it: Whether something is Kiki or whether it is Bouba. 

Some sources and literature
- “Bouba/kiki effect”, in Wikipedia, https://en.wikipedia.org/wiki/Bouba/kiki_effect
- Peiffer-Smadja, Nathan; Laurent Cohen, “The cerebral bases of the bouba-kiki effect”, on https://www.sciencedirect.com/science/article/pii/S1053811918321141
- Ramachandran, V.S,; E.M. Hubbard, “Synaesthesia – a window into perception, thought and language.” Journal of  Consciousness Studies, 2001/8: 3-34.
- “What is the Kiki-Bouba test?”, on https://brainstuff.org/blog/what-is-the-kiki-bouba-test
- Shukla, Aditya, “The Kiki Bouba effect – research overview & explanation”, on https://cognitiontoday.com/the-kiki-bouba-effect-research-overview-explanation/#The_Kiki-Bouba_effect