Language
Shape-Word Matching Task
Also called: bouba/kiki task, bouba-kiki test, maluma/takete task, sound-shape matching task, sound symbolism task
Measure the bouba/kiki effect: participants choose whether a written made-up word names a rounded or a spiky shape, in 80 choices, with the same words in eight languages.
4-6 minUntimed
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Preview any test free after you sign up.
- Papers, 2021 to 2025
- 74
- Evidence grade
- D
- Registered clinical studies
- 0
What it measures
Measures the bouba/kiki effect, how people match the sounds of words with shapes. Each screen shows a written made-up word, such as "monubo" or "tekepi", and a rounded and a spiky shape, and participants choose the shape the word names. The main score is the percent of choices that follow the sounds. The words are written; no sound is played.
Constructs
- Sound symbolism
- Cross-modal correspondence
- Language
- Shape perception
Research uses
- Sound symbolism and cross-modal research
- Language and reading research
- Cross-linguistic comparison
- Within-study group comparison
How the paradigm works
The Shape-Word Matching Task measures the bouba/kiki effect: most people give a made-up word with soft, rounded sounds, such as "bouba", to a rounded shape, and one with sharp sounds, such as "kiki", to a spiky shape. Köhler (1929, 1947) showed it with "maluma" and "takete", and Ramachandran and Hubbard (2001) with "bouba" and "kiki". Ćwiek and colleagues (2022) found it in speakers of 25 languages written in 10 scripts, with an estimated 72% matching both words, and published matches pool to 89% when the words use the classic sounds and could be words of the listener's language (Styles and Gawne, 2017).
More about the paradigm
Each screen shows one written made-up word above two shapes our code draws, a rounded blob and a spiky star of the same area and color, after the radial patterns of Chen and colleagues (2016), and the participant chooses the shape the word names. Round-sounding words use b, m and n with o and u, such as "monubo"; spiky-sounding words use k, t and p with i and e, such as "tekepi", the sounds that carry the effect, consonants most of all (Nielsen and Rendall, 2011; Fort, Martin and Peperkamp, 2015). There are 20 words of each kind and 40 shape pairs. Each pair appears once in each half of the session, once with a round word and once with a spiky word, so a session makes 80 choices by default, with the rounded shape on each side for half the screens of each kind of word. The words are the same in all eight languages, written in katakana in Japanese, and were checked against word lists of the eight languages so that none is a word. There is no time limit and no right answer. Two practice screens with neutral words and shapes come first.
The words are written and no sound is played, so the test measures the effect as people read. In literate adults the curve of the letters adds to it (Cuskley, Simner and Kirby, 2017); the katakana of Japanese sessions carry little of that (Ćwiek and colleagues, 2022). The main score is the percent of choices that follow the sounds, where 50 is chance. The test also reports the same for round and spiky words, the percent of pairs matched both ways, the share of choices that took the rounded shape whatever the word, the share on the left and the median choice time.
Scores
- Sound-Symbolic Matches%
- Percent of choices that follow the sounds: the rounded shape for a round word and the spiky shape for a spiky word.
- 50 is chance; higher means more choices follow the sounds
- Round-Word Matches%
- Percent of round-word screens on which the rounded shape was chosen.
- 50 is chance
- Spiky-Word Matches%
- Percent of spiky-word screens on which the spiky shape was chosen.
- 50 is chance
- Pairs Matched Both Ways%
- Of the pairs answered twice, the percent where both words went to their own shape.
- 25 is chance
- Rounded Shape Chosen%
- Percent of all choices that took the rounded shape, whatever the word.
- Near 50 when the choices follow the words; 90 or more, or 10 or less, is flagged
- Left Choices%
- Percent of choices on the left.
- Informational
- Median Choice Timems
- Median time from the screen appearing to a choice, leaving out choices under 100 ms.
- Informational
- Choicescount
- Screens answered in the test.
- Fewer than 90% of those planned invalidates
- Planned Choicescount
- Screens the session set out to show.
- Informational
- Anticipationscount
- Choices under 100 ms.
- Lower supports interpretation
Use and evidence
74 papers from 2021 to 2025 name this task in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 216 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 23 |
| 2024 | 10 |
| 2023 | 16 |
| 2022 | 11 |
| 2021 | 14 |
| 2020 | 8 |
| 2019 | 24 |
| 2018 | 17 |
| 2017 | 16 |
| 2016 | 14 |
| 2015 | 9 |
| 2014 | 10 |
| 2013 | 7 |
| 2012 | 4 |
| 2011 | 3 |
| 2010 | 3 |
| 2009 | 0 |
| 2008 | 1 |
| 2007 | 1 |
| 2006 | 2 |
| 2005 | 0 |
| 2004 | 0 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 0 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade D
Little published measurement evidence found.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 5
- Registered clinical studies using it as an outcome
- 0
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.14.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Words
- 20 round-sounding words (b, m and n with o and u) and 20 spiky-sounding words (k, t and p with i and e), three syllables each, written for this test and checked against word lists of the eight app languages. Japanese sessions show them in katakana.
- Shapes
- 40 pairs our code draws: a rounded blob of 4 to 6 lobes and a spiky star of 7 to 11 points, of the same area and gray.
- Session
- 40 pairs by default, or 24 or 32 as a setting. Each pair appears once in each half, once with a word of each kind, so 80 choices by default.
- Order
- The rounded shape is on each side for half the screens of each kind of word, with no more than 3 words of one kind or 3 rounded shapes on one side in a row. The session's seed draws every screen, and all of it is saved.
- Answer
- A click or tap on a shape, with no time limit and no right answer.
- Practice
- 2 screens with neutral words and two smooth shapes.
- No sound
- The words are written, and no sound is played. In literate adults the curve of the letters adds to the effect (Cuskley and colleagues, 2017).
The words and shapes were made for this test. There are no percentiles or score ranges: a preference has no better direction. Scores support research and do not diagnose.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: bouba_kiki_choice test rows from the scored run, one choice of two shapes per screen, with no right answer; the rounded shape is on each side for half the screens of each kind of word. The same side on every screen invalidates. Choices under 200 ms on at least half the screens invalidate. Fewer than 90% of the planned choices invalidate. One kind of shape on at least 90% of screens is flagged for review. A hidden tab is flagged.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. The same side on every screen means the words and shapes were not looked at. An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast. The score is a share of choices, so it needs nearly all of them. Choosing one kind of shape whatever the word is a possible answer, but it says nothing about the words, so it is flagged; the limits are ConductScience choices.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Shape pairs | 40 pairs (80 choices, standard) | 24 pairs (48 choices), 32 pairs (64 choices), 40 pairs (80 choices, standard) |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Untimed test: runs on desktops, laptops, tablets and phones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Shape-Word Matching Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Köhler W, 1929, 1947; Ramachandran VS, Hubbard EM, 2001; Styles SJ, Gawne L, 2017; Ćwiek A and colleagues, 2022), with the standard settings (shape pairs: 40 pairs (80 choices, standard)). The main score was sound-symbolic matches (percent of choices that follow the sounds: the rounded shape for a round word and the spiky shape for a spiky word).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Köhler, W. (1947). Gestalt psychology (2nd ed.). Liveright. The first sound-shape matches, with maluma and takete.
- Ramachandran, V. S., & Hubbard, E. M. (2001). Synaesthesia: A window into perception, thought and language. Journal of Consciousness Studies, 8(12), 3-34. The names bouba and kiki.
- Ćwiek, A., Fuchs, S., Draxler, C., Asu, E. L., Dediu, D., Hiovain, K., Kawahara, S., Koutalidis, S., Krifka, M., Lippus, P., Lupyan, G., Oh, G. E., Paul, J., Petrone, C., Ridouane, R., Reiter, S., Schümchen, N., Szalontai, Á., Ünal-Logacev, Ö., Zeller, J., Perlman, M., & Winter, B. (2022). The bouba/kiki effect is robust across cultures and writing systems. Philosophical Transactions of the Royal Society B, 377(1841), 20200390. https://doi.org/10.1098/rstb.2020.0390
- Styles, S. J., & Gawne, L. (2017). When does maluma/takete fail? Two key failures and a meta-analysis suggest that phonology and phonotactics matter. i-Perception, 8(4). https://doi.org/10.1177/2041669517724807The sounds of the words, and words that could belong to each language.
- Chen, Y.-C., Huang, P.-C., Woods, A., & Spence, C. (2016). When "Bouba" equals "Kiki": Cultural commonalities and cultural differences in sound-shape correspondences. Scientific Reports, 6, 26681. https://doi.org/10.1038/srep26681Shapes drawn as radial patterns.
- Cuskley, C., Simner, J., & Kirby, S. (2017). Phonological and orthographic influences in the bouba-kiki effect. Psychological Research, 81(1), 119-130. https://doi.org/10.1007/s00426-015-0709-2The part letter shapes play when the words are written.
Source papers
- Ćwiek A, Fuchs S, Draxler C, and colleagues (2022). The bouba/kiki effect is robust across cultures and writing systems. Philosophical Transactions of the Royal Society B, 377(1841):20200390.N 917, Adults
Questions
How long does the Shape-Word Matching Task take?
About 4 to 6 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Sound-Symbolic Matches, Round-Word Matches, Spiky-Word Matches, Pairs Matched Both Ways, Rounded Shape Chosen, Left Choices, Median Choice Time, Choices, Planned Choices and Anticipations. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Shape-Word Matching Task used in research?
74 papers from 2021 to 2025 name it in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 216 of 395 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.14.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Shape-Word Matching Task have?
In the published research, 0 papers report its test-retest reliability and 0 registered clinical studies use it as an outcome (evidence grade D in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Shape pairs (24 pairs (48 choices), 32 pairs (64 choices), 40 pairs (80 choices, standard)). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. Its words are made up and the same in every language, written in Latin letters, or in katakana in Japanese sessions. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
Every test: the full test list.
Run this test in your next study
Start free with 10 free participants on any test, then use participant credits or a yearly plan.