The Bouba/Kiki Effect

Another brainteaser this week, on a test which any psychology student would recognise.

First, have a look at these shapes. Which one would you call ‘bouba’ and which one would you call ‘kiki’? Once you’ve done this, scroll down to see the answer.



In fact, these shapes have not been officially named, but 95% of people asked this question name the shape on the left ‘kiki’ and the shape on the right ‘bouba’. This is amazing considering that this is a free choice, with a 50/50 answer. It seems to be that each shape is better suited to a certain name. But why?

The experiment shown above was carried out by Ramanchandran & Hubbard (2001) as part of their work on synaesthesia – a condition in which people’s senses overlap e.g. hearing sounds as viewing colours. If you’d like to read more about synaesthesia check out my blog post. Their hypothesis as to why synaesthesia occurs is that it is caused by extra connections in the brain between senses.

The authors proposed that the reason most people identify the spiky shape as ‘kiki’ and the rounded shape as ‘bouba’ because the shape of the objects mimic the phonetics of the sounds of the names when spoken. This is therefore evidence that most people, even though they do not have synaesthesia, have connections in their brain between the different senses.

Although this might just seem like a fun, but pretty trivial experiment, the results actually have profound implications for our view on how language began in the first place. As 95% of people map the same sounds to these objects, the authors suggest that there might be ‘natural constraints’ on how sounds and objects are linked. They also suggested that the representation of a word in the motor cortex (to form the shapes to speak the word) and auditory areas are linked to the visual appearance of the object, which again shows these cross-modal connections at work.


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