Bouba/kiki effect

The bouba/kiki effect is a non-arbitrary mapping between speech sounds and the visual shape of objects. It was first documented by Wolfgang Köhler in 1929 using nonsense words. The effect has been observed in American university students, Tamil speakers in India, young children, and infants, and has also been shown to occur with familiar names. It is absent in individuals who are congenitally blind and reduced in autistic individuals. The effect was investigated using fMRI in 2018.[1] The bouba/kiki effect is one form of sound symbolism.[2]

Booba and Kiki shapes
This picture is used as a test to demonstrate that people may not attach sounds to shapes arbitrarily: American college undergraduates and Tamil speakers in India called the shape on the left "kiki" and the one on the right "bouba".



The bouba/kiki effect was first observed by German American psychologist Wolfgang Köhler in 1929.[3] In psychological experiments first conducted on the island of Tenerife (where the primary language is Spanish), Köhler showed forms similar to those shown at the right and asked participants which shape was called "takete" and which was called "baluba" ("maluma" in the 1947 version). Although not explicitly stated, Köhler implies that there was a strong preference to pair the jagged shape with "takete" and the rounded shape with "baluba".[4]

Extension to other contextsEdit

In 2001, Vilayanur S. Ramachandran and Edward Hubbard repeated Köhler's experiment using the words "kiki" and "bouba" and asked American college undergraduates and Tamil speakers in India "Which of these shapes is bouba and which is kiki?" In both groups, 95% to 98% selected the curvy shape as "bouba" and the jagged one as "kiki", suggesting that the human brain somehow attaches abstract meanings to the shapes and sounds in a consistent way.[5][failed verificationsee discussion]

Daphne Maurer and colleagues showed that even children as young as 2½ years old may show this preference.[6] More recent work by Ozturk and colleagues (2013) showed that even 4-month-old infants have the same sound–shape mapping biases as adults and toddlers.[7] Infants are able to differentiate between congruent trials (pairing an angular shape with 'kiki' or a curvy shape with 'bubu') and incongruent trials (pairing a curvy shape with 'kiki' or an angular shape with 'bubu'). Infants looked longer at incongruent pairings than at congruent pairings. Infants' mapping was based on the combination of consonants and vowels in the words and neither consonants nor vowels alone sufficed for mapping. These results suggest that some sound–shape mappings precede language learning, and may in fact aid in language learning by establishing a basis for matching labels to referents and narrowing the hypothesis space for young infants. Adults in this study, like infants, used a combination of consonant and vowel information to match the labels they heard with the shapes they saw. However, this was not the only strategy that was available to them. Adults, unlike infants, were also able to use consonant information alone and vowel information alone to match the labels to the shapes, albeit less frequently than the consonant–vowel combination. When vowels and consonants were put in conflict, adults used consonants more often than vowels.

The effect has also been shown to emerge in other contexts. For example, when words are paired with evaluative meanings (with "bouba" words associated with positive concepts and "kiki" words associated with negative concepts)[8] or when the words to be paired are existing first names, suggesting that some familiarity with the linguistic stimuli does not eliminate the effect. A study showed that individuals will pair names such as "Molly" with round silhouettes, and names such as "Kate" with sharp silhouettes. Moreover, individuals will associate different personality traits with either group of names (e.g., easygoingness with "round names"; determination with "sharp names"). This may hint at a role of abstract concepts in the effect.[9]

Contexts where the effect is smaller or absentEdit

Other research suggests that this effect does not occur in all communities,[10] and it appears that the effect breaks if the sounds do not make licit words in the language.[11] The bouba/kiki effect seems to be dependent on a long sensitive period, with high visual capacities in childhood being necessary for its typical development. In contrast to typically sighted individuals, congenitally blind individuals have been reported not to show a systematic bouba/kiki effect for touched shapes.[12][13] Autistic individuals do not show as strong a preference. Individuals without autism agree with the standard result 88% of the time, while individuals with autism agree only 56% of the time.[14]


In 2019, Nathan Peiffer-Smadja and Laurent Cohen published the first study using fMRI to explore the bouba/kiki effect.[1] They found that prefrontal activation is stronger to mismatching (bouba with spiky shape) than to matching (bouba with round shape) stimuli. A subsequent study by Kelly McCormick and colleagues reported a similar pattern of greater activation for mismatched word-shape stimuli, but with most activity in parietal regions including the intraparietal sulcus (IPS) and supramarginal gyrus (SMG), regions known to play a role in sensory association and perceptual-motor processing.[15] Interestingly, Peiffer-Smadja and Cohen also found that sound–shape matching also influences activations in the auditory and visual cortices, suggesting an effect of matching at an early stage in sensory processing.[1]

Implications for understanding languageEdit

Ramachandran and Hubbard suggest that the kiki/bouba effect has implications for the evolution of language, because it suggests that the naming of objects is not completely arbitrary.[5]: 17  The rounded shape may most commonly be named "bouba" because the mouth makes a more rounded shape to produce that sound while a more taut, angular mouth shape is needed to make the sounds in "kiki".[16] Alternatively, the distinction may be between coronal or dorsal consonants like /k/ and labial consonants like /b/.[17] Additionally, it was shown that it is not only different consonants (e.g., voiceless versus voiced) and different vowel qualities (e.g., /a/ versus /i/) that play a role in the effect, but also vowel quantity (long versus short vowels). In one study, participants rated words containing long vowels to refer to longer objects and short vowels to short objects.[18] The presence of these "synesthesia-like mappings" suggest that this effect might be the neurological basis for sound symbolism, in which sounds are non-arbitrarily mapped to objects and events in the world.[citation needed] Research has also indicated that the effect may be a case of ideasthesia,[19] a phenomenon in which activations of concepts (inducers) evoke perception-like experiences (concurrents). The name comes from the Greek idea and aisthesis, meaning "sensing concepts" or "sensing ideas", and was introduced by Danko Nikolić.[20]

In mediaEdit

The experiment was reproduced in episode 3 of season 4 of the television show Brain Games with the names "takete" and "maluma." One participant expressed her association of takete and maluma with their respective shapes by comparing them to the rigid movement of a toy soldier and the swaying of the hula, respectively. A similar experiment included the association of the name "lomba" with a fictitious brand of milk chocolate and "kitiki" with a fictitious brand of dark chocolate.[citation needed] The creator of indie game Baba is You has confirmed that the main characters, Baba and Keke, are named after the Bouba/kiki effect.

See alsoEdit


  1. ^ a b c Peiffer-Smadja, Nathan; Cohen, Laurent (2019-02-01). "The cerebral bases of the bouba-kiki effect". NeuroImage. 186: 679–689. doi:10.1016/j.neuroimage.2018.11.033. ISSN 1053-8119. PMID 30503933. S2CID 54164828.
  2. ^ Margiotoudi Konstantina and Pulvermüller Friedemann (2020). "Action sound–shape congruencies explain sound symbolism". Scientific Reports. 10 (1): 12706. Bibcode:2020NatSR..1012706M. doi:10.1038/s41598-020-69528-4. PMC 7392762. PMID 32728096. ProQuest 2428279185.
  3. ^ Köhler, Wolfgang (1929). Gestalt Psychology. New York: Liveright.
  4. ^ Köhler, Wolfgang (1947). Gestalt Psychology (2nd ed.). New York: Liveright. p. 133.
  5. ^ a b Ramachandran, V.S. & Hubbard, E.M. (2001). "Synaesthesia: A window into perception, thought and language" (PDF). Journal of Consciousness Studies. 8 (12): 3–34.
  6. ^ Maurer, Daphne; Pathman, Thanujeni & Mondloch, Catherine J. (2006). "The shape of boubas: Sound-shape correspondences in toddlers and adults" (PDF). Developmental Science. 9 (3): 316–322. doi:10.1111/j.1467-7687.2006.00495.x. PMID 16669803. Archived from the original (PDF) on 2011-07-23. Retrieved 2011-06-19.
  7. ^ Ozturk, Ozge; Krehm, Madelaine; Vouloumanos, Athena (2013). "Sound symbolism in infancy: Evidence for sound–shape cross-modal correspondences in 4-month-olds" (PDF). Journal of Experimental Child Psychology. 114 (2): 173–186. doi:10.1016/j.jecp.2012.05.004. PMID 22960203. Archived from the original (PDF) on 2020-08-17. Retrieved 2019-09-24.
  8. ^ Bross, Fabian (2018). "The Good, the Bad, the Bouba, and the Kiki. Cross-Modal Correspondences Between Evaluative Meanings, Speech-Sounds, and Object Shapes". 14th conference "Phonetics & Phonology in the German-Speaking World". University of Vienna. doi:10.13140/RG.2.2.11463.14240.
  9. ^ Sidhu, David M.; Pexman, Penny M. (2015-05-27). "What's in a Name? Sound Symbolism and Gender in First Names". PLOS ONE. 10 (5): e0126809. Bibcode:2015PLoSO..1026809S. doi:10.1371/journal.pone.0126809. ISSN 1932-6203. PMC 4446333. PMID 26016856.
  10. ^ Rogers, Susan K.; Ross, Abraham S. (1975). "A cross-cultural test of the maluma–takete phenomenon". Perception. 4 (1): 105–106. doi:10.1068/p040105. PMID 1161435. S2CID 30045028.
  11. ^ Syles, Suzy; Gawne, Lauren (2017). "When Does Maluma/Takete Fail? Two Key Failures and a Meta-Analysis Suggest That Phonology and Phonotactics Matter". i-Perception. 8 (4): 204166951772480. doi:10.1177/2041669517724807. PMC 5574486. PMID 28890777.
  12. ^ Fryer, Louise; Freeman, Jonathan & Pring, Linda (2014). "Touching words is not enough: How visual experience influences haptic–auditory associations in the "Bouba–Kiki" effect" (PDF). Cognition. 132 (2): 164–173. doi:10.1016/j.cognition.2014.03.015. PMID 24809744. S2CID 29605784.
  13. ^ Hamilton-Fletcher, Giles; Pisanski, Katarzyna; Reby, David; Stefańczyk, Michał; Ward, Jamie & Sorokowska, Agnieszka (2018). "The role of visual experience in the emergence of cross-modal correspondences" (PDF). Cognition. 175: 114–121. doi:10.1016/j.cognition.2018.02.023. PMID 29502009. S2CID 3688492.
  14. ^ Oberman, Lindsay M. & Ramachandran, Vilayanur S. (2008). "Preliminary evidence for deficits in multisensory integration in autism spectrum disorders: the mirror neuron hypothesis". Social Neuroscience. 3 (3–4): 348–355. doi:10.1080/17470910701563681. PMID 18979385. S2CID 6126657.
  15. ^ McCormick, Kelly; Lacey, Simon; Stilla, Randall; Nygaard, Lynne C.; Sathian, K. (2021-08-11). "Neural Basis of the Sound-Symbolic Crossmodal Correspondence Between Auditory Pseudowords and Visual Shapes". Multisensory Research. -1 (aop): 1–50. doi:10.1163/22134808-bja10060. ISSN 2213-4794. S2CID 236998825.
  16. ^ D’Onofrio, Annette (2013). "Phonetic Detail and Dimensionality in Sound-shape Correspondences: Refining the Bouba-Kiki Paradigm". Language and Speech. 57 (3): 367–393. CiteSeerX doi:10.1177/0023830913507694. S2CID 51937587.
  17. ^ McCormick, Kelly; Kim, Jee Young; List, Sara; Nygaard, Lynne C. (2015). "Sound to Meaning Mappings in the Bouba-Kiki Effect" (PDF). Proceedings of the 37th Annual Conference of the Cognitive Science Society: Mind, Technology, and Society: Pasadena, California, 23–25 July 2015. Austin, TX: Cognitive Science Society. pp. 1565–1570. ISBN 978-0-9911967-2-2.
  18. ^ Bross, Fabian (2018). "Cognitive associations between vowel length and object size: A new feature contributing to a bouba/kiki effect". In Belz, M.; Mooshammer, C.; Fuchs, S.; Jannedy, S.; Rasskazova, O.; Zygis, M. (eds.). Proceedings of the Conference on Phonetics & Phonology in German-Speaking Countries. 13. Berlin: Humbold University. pp. 17–20.
  19. ^ Gómez Milán, E.; Iborra, O.; de Córdoba, M.J.; Juárez-Ramos, V.; Rodríguez Artacho, M.A.; Rubio, J.L. (2013). "The Kiki-Bouba effect: A case of personification and ideaesthesia". Journal of Consciousness Studies. 20 (1–2): 84–102.
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