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Shape Science: The Bouba-Kiki Effect

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Bouba or Kiki?: This experiment's results may reveal something about the origins of language. Image: George Retseck

Key concepts
Language
Speech
Shapes
Sound
Psychology
Human behavior

Introduction
Do shapes have certain "sounds" to people, regardless of what language people speak? For example, does everyone associate certain physical characteristics, like sharpness and roundedness, with certain sounds? Understanding such similarities may not only help people better understand how languages develop, but it may also improve people's ability to communicate, especially when trying to cross language barriers. In this activity you'll investigate the "Bouba–Kiki effect" to find out how abstract shapes may be linked to sound.

Background
One of the most amazing things humans do is use language to communicate. People have developed languages over many tens or hundreds of thousands of years, resulting in many very different tongues being spoken around the world today. How did our ability to use language evolve? Where and when was it first used?

One idea is that the first languages were representative sounds that people linked to concepts. Eventually these meaningful sounds grew more diverse and structurally intricate as they evolved into more complex speech. This idea brings with it a major question: Were the first sounds made by humans arbitrary and random, or were they consistently applied to certain symbols and concepts? A psychological phenomenon called the Bouba–Kiki effect has been used to help answer this question. In this effect, people are shown a pointy picture or a curvy, bubbly shape and asked to identify it as "Bouba" or "Kiki," even though those are both nonsense words. They are asked to do the same with a pointy, sharper shape. A surprising number of people identify the round shape as "Bouba" and the pointy shape as "Kiki" although they have not been told what the words mean. Will you observe the Bouba–Kiki effect or will you have the results of a 50–50 random-chance event?

Materials
•   A pen, pencil, or marker. You can use a colorful assortment if you want!
•   20 index cards
•   A piece of paper
•   At least five volunteers

Preparation
•   On 10 index cards, draw a pointy, star-like shape, like the one shown in the illustration above.
•   On the other 10 index cards, draw round, bubbly shapes—like the one in the illustration above.
•   Randomly mix the cards by shuffling all of them together a few times.

Procedure
•   Tell your first volunteer that you will show them a series of cards, and that you want to know if the picture is Bouba or Kiki, but do not tell them what Bouba or Kiki mean.
•   If they ask you for a definition, just explain that they are supposed to guess and do their best to decide.
•   Show your volunteer the cards, one at a time.
•   On a piece of paper keep track of the number of "correct" and "incorrect" answers. "Correct" answers are when the volunteer identifies a pointy, starlike shape with Kiki or a round, bubbly shape with Bouba. (Note that the answers your volunteers give you are not actually correct or incorrect, because "Bouba" and "Kiki" are made-up words.)
•   How many correct answers did the volunteer give? Did the volunteer give any incorrect ones, matching Kiki with the round shape or Bouba with the pointy shape?
•   Repeat these steps with at least five more volunteers. Use the same deck of index cards each time, but shuffle it so that the cards are randomly mixed.
•   When you finished, what was the total number of correct responses and the total number of incorrect responses from all volunteers? Did the volunteers mostly give correct responses?
•   Extra: Try to find volunteers from a series of different age groups and do this activity again. Does the Bouba–Kiki effect differ by age group? What is the youngest group in which you can observe the effect?
•   Extra: Give a new volunteer a piece of paper and ask the volunteer to draw something that is Bouba or Kiki. Try this with several new volunteers, collect all of the drawings, and score them for being pointy or rounded in shape. How well does this work? Does the volunteer always make a Bouba drawing rounded and a Kiki one pointy?
•   Extra: If you know people who speak different languages, try this activity on them. Does it still work?
•   Extra: What is it about the words "Bouba" and "Kiki" that make this work? Try this activity again but this time swap the vowel sounds by using the words "Bee-Bee" and "Kooka" instead of "Bouba" and "Kiki" when volunteers look at the drawings. Are the results the same, or do your results switch around? If they're the same, then perhaps the consonant sounds of the "B" and the "K" are most important, but if they're switched, then the vowel sounds of the "ee" and "oo" may be more important.


2 Comments

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  1. 1. craigayre 08:38 AM 11/20/12

    I suspect this has more to do with evolutionary survival than words. Spiky things are often dangerous: thorns, teeth, stings, spears, arrows etc. Generally alarm calls have a higer frequency, resulting in shriek (theres an onomatopeic example) sounds with lots of "eee" in it, with the volume and frequency carrying some quantitative information about the severity of the hazard. Therefore the sounds we would use to describe spiky things would sound more shrill and alarming. I doubt this is learned, but hard-wired by natural selection. I suspect the link in the brain would be:
    1. determine extent of hazard of shape.
    2. Determine sound which would communicate hazard.
    3. Communicate hazard with shrill sound.

    Less hazardous things will therefore be communitcated in the opposite way with sounds of lower frequency. Round things are often less hazardous: Apples, sponges, balls etc. I reckon we call spiky shapes KiKi because natural selection which has resulted in greater success of individuals who could communicate potential hazards effectively.

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  2. 2. fabiuz2609 in reply to craigayre 12:05 PM 11/22/12

    Your hypothesis would be quite easy to disprove, if false. As suggested in the article, just check if the same phenomenon occurs in other countries, for different languages (as for me, in Italy, I would have made the same association). If indeed the kiki/bouba effect is an evolutionary adaptation connected to sound frequency and danger, it should be independent by spoken language. If, on the contrary, results point to language correlation, then it cannot be. Many languages simply make larger use of specific consonants or vowels at the expense of others. So I guess there are languages for which the bouba-kiki effect doesn't appear, or it appears in such a different form to invalidate your hypotesis. It's only a guess, anyway.

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