Chimp test: method
Numerical masking task (after Inoue & Matsuzawa, 2007), adaptive length
Scorer version: 1 (board version 1 for seeded challenge boards)
← Back to the testWhat it measures
Visuospatial short-term memory for the positions of several items and their serial order, after one self-paced look.
Procedure
A grid of 8 × 5 cells (shown 5 × 8 on narrow screens). The first round shows the numbers 1 to 4 in random, distinct cells. Viewing time is unlimited; when the visitor taps 1, all other numbers turn into identical blank squares, and the remaining cells must be tapped in ascending order. A round with every tap in order adds one number to the next round. A wrong tap is a strike, and the round restarts with the same count at new positions. Three strikes in total end the game. Maximum 40 numbers (the whole grid). Input: touch or mouse; no practice. Modes: normal (random boards), daily challenge (boards seeded by the UTC date) and friend challenge (the same seeded boards from a shared link).
Parameters
| Parameter | Value |
|---|---|
| Grid | 8 × 5 cells (transposed on narrow screens) |
| Numbers in the first round | 4 |
| Increase after a clean round | +1 |
| Strikes that end the game | 3 (cumulative) |
| Maximum numbers | 40 |
| Viewing time | unlimited, until the first tap |
| Practice | none |
| Inputs | touch, mouse |
Scoring
Score = the largest number of items completed in one clean round (all taps in order 1 … N); higher is better. Also reported: the number of rounds and strikes.
Valid-run rules
At least 1 and at most 83 rounds; tapped values must lie between 1 and 40; scoring stops at the third strike. Daily-challenge runs need a seed that matches the UTC date. In normal mode the server takes the round sizes from the page's log and does not regenerate the boards.
Differences from the classic task
Inoue and Matsuzawa (2007) tested chimpanzees and humans on a touchscreen with the numerals 1 to 9 in two versions: a masking task (the others turn white when the first numeral is touched, as here) and a limited-hold task (numerals shown for as little as 210 ms). This version uses only the self-paced masking variant, has adaptive length beyond 9 items and a three-strike rule, and runs on consumer screens of any size.
Limitations
Scores rise steeply with practice (Silberberg & Kearns, 2009), so first runs mostly reflect learning the task. Screen size changes the spatial layout. Strategies (grouping, naming positions) vary between players. Unsupervised setting. Not a clinical measure.
Languages and review status
Language-independent stimuli, instructions in all site languages.
Review status by instruction language
Published instruction languages are listed below. Translation method: machine-assisted translation with automated script and spelling checks. Language-specific material is described above; native-speaker review is not documented here.
| Instruction language | Documented review status |
|---|---|
| English | Original English text. |
| Afaan Oromoo | Automated script and spelling checks; native-speaker review not documented. |
| Afrikaans | Automated script and spelling checks; native-speaker review not documented. |
| Akan | Automated script and spelling checks; native-speaker review not documented. |
| Azərbaycan dili | Automated script and spelling checks; native-speaker review not documented. |
| Bahasa Indonesia | Automated script and spelling checks; native-speaker review not documented. |
| Bahasa Melayu | Automated script and spelling checks; native-speaker review not documented. |
| Bosanski | Automated script and spelling checks; native-speaker review not documented. |
| Català | Automated script and spelling checks; native-speaker review not documented. |
| Čeština | Automated script and spelling checks; native-speaker review not documented. |
| Chichewa | Automated script and spelling checks; native-speaker review not documented. |
| ChiShona | Automated script and spelling checks; native-speaker review not documented. |
| Dansk | Automated script and spelling checks; native-speaker review not documented. |
| Deutsch | Automated script and spelling checks; native-speaker review not documented. |
| Eesti | Automated script and spelling checks; native-speaker review not documented. |
| Español | Automated script and spelling checks; native-speaker review not documented. |
| Filipino | Automated script and spelling checks; native-speaker review not documented. |
| Français | Automated script and spelling checks; native-speaker review not documented. |
| Galego | Automated script and spelling checks; native-speaker review not documented. |
| Hausa | Automated script and spelling checks; native-speaker review not documented. |
| Hmoob | Automated script and spelling checks; native-speaker review not documented. |
| Hrvatski | Automated script and spelling checks; native-speaker review not documented. |
| Igbo | Automated script and spelling checks; native-speaker review not documented. |
| Ikinyarwanda | Automated script and spelling checks; native-speaker review not documented. |
| isiXhosa | Automated script and spelling checks; native-speaker review not documented. |
| isiZulu | Automated script and spelling checks; native-speaker review not documented. |
| Italiano | Automated script and spelling checks; native-speaker review not documented. |
| Kiswahili | Automated script and spelling checks; native-speaker review not documented. |
| Kurmancî | Automated script and spelling checks; native-speaker review not documented. |
| Latviešu | Automated script and spelling checks; native-speaker review not documented. |
| Lietuvių | Automated script and spelling checks; native-speaker review not documented. |
| Lingála | Automated script and spelling checks; native-speaker review not documented. |
| Magyar | Automated script and spelling checks; native-speaker review not documented. |
| Malagasy | Automated script and spelling checks; native-speaker review not documented. |
| Nederlands | Automated script and spelling checks; native-speaker review not documented. |
| Norsk bokmål | Automated script and spelling checks; native-speaker review not documented. |
| Oʻzbekcha | Automated script and spelling checks; native-speaker review not documented. |
| Polski | Automated script and spelling checks; native-speaker review not documented. |
| Português | Automated script and spelling checks; native-speaker review not documented. |
| Română | Automated script and spelling checks; native-speaker review not documented. |
| Sesotho | Automated script and spelling checks; native-speaker review not documented. |
| Setswana | Automated script and spelling checks; native-speaker review not documented. |
| Shqip | Automated script and spelling checks; native-speaker review not documented. |
| Slovenčina | Automated script and spelling checks; native-speaker review not documented. |
| Slovenščina | Automated script and spelling checks; native-speaker review not documented. |
| Soomaali | Automated script and spelling checks; native-speaker review not documented. |
| Srpski | Automated script and spelling checks; native-speaker review not documented. |
| Suomi | Automated script and spelling checks; native-speaker review not documented. |
| Svenska | Automated script and spelling checks; native-speaker review not documented. |
| Tiếng Việt | Automated script and spelling checks; native-speaker review not documented. |
| Türkçe | Automated script and spelling checks; native-speaker review not documented. |
| Türkmençe | Automated script and spelling checks; native-speaker review not documented. |
| Yorùbá | Automated script and spelling checks; native-speaker review not documented. |
| Ελληνικά | Automated script and spelling checks; native-speaker review not documented. |
| Български | Automated script and spelling checks; native-speaker review not documented. |
| Кыргызча | Automated script and spelling checks; native-speaker review not documented. |
| Қазақ тілі | Automated script and spelling checks; native-speaker review not documented. |
| Македонски | Automated script and spelling checks; native-speaker review not documented. |
| Монгол | Automated script and spelling checks; native-speaker review not documented. |
| Русский | Automated script and spelling checks; native-speaker review not documented. |
| Татарча | Automated script and spelling checks; native-speaker review not documented. |
| Тоҷикӣ | Automated script and spelling checks; native-speaker review not documented. |
| Українська | Automated script and spelling checks; native-speaker review not documented. |
| ქართული | Automated script and spelling checks; native-speaker review not documented. |
| Հայերեն | Automated script and spelling checks; native-speaker review not documented. |
| עברית | Automated script and spelling checks; native-speaker review not documented. |
| ئۇيغۇرچە | Automated script and spelling checks; native-speaker review not documented. |
| اردو | Automated script and spelling checks; native-speaker review not documented. |
| العربية | Automated script and spelling checks; native-speaker review not documented. |
| پښتو | Automated script and spelling checks; native-speaker review not documented. |
| پنجابی | Automated script and spelling checks; native-speaker review not documented. |
| سنڌي | Automated script and spelling checks; native-speaker review not documented. |
| فارسی | Automated script and spelling checks; native-speaker review not documented. |
| کوردیی ناوەندی | Automated script and spelling checks; native-speaker review not documented. |
| ትግርኛ | Automated script and spelling checks; native-speaker review not documented. |
| አማርኛ | Automated script and spelling checks; native-speaker review not documented. |
| कोंकणी | Automated script and spelling checks; native-speaker review not documented. |
| नेपाली | Automated script and spelling checks; native-speaker review not documented. |
| मराठी | Automated script and spelling checks; native-speaker review not documented. |
| मैथिली | Automated script and spelling checks; native-speaker review not documented. |
| हिन्दी | Automated script and spelling checks; native-speaker review not documented. |
| অসমীয়া | Automated script and spelling checks; native-speaker review not documented. |
| বাংলা | Automated script and spelling checks; native-speaker review not documented. |
| ਪੰਜਾਬੀ | Automated script and spelling checks; native-speaker review not documented. |
| ગુજરાતી | Automated script and spelling checks; native-speaker review not documented. |
| ଓଡ଼ିଆ | Automated script and spelling checks; native-speaker review not documented. |
| தமிழ் | Automated script and spelling checks; native-speaker review not documented. |
| తెలుగు | Automated script and spelling checks; native-speaker review not documented. |
| ಕನ್ನಡ | Automated script and spelling checks; native-speaker review not documented. |
| മലയാളം | Automated script and spelling checks; native-speaker review not documented. |
| සිංහල | Automated script and spelling checks; native-speaker review not documented. |
| ไทย | Automated script and spelling checks; native-speaker review not documented. |
| ລາວ | Automated script and spelling checks; native-speaker review not documented. |
| မြန်မာ | Automated script and spelling checks; native-speaker review not documented. |
| ខ្មែរ | Automated script and spelling checks; native-speaker review not documented. |
| 한국어 | Automated script and spelling checks; native-speaker review not documented. |
| 日本語 | Automated script and spelling checks; native-speaker review not documented. |
| 简体中文 | Automated script and spelling checks; native-speaker review not documented. |
| 粵語 | Automated script and spelling checks; native-speaker review not documented. |
| 繁體中文 | Automated script and spelling checks; native-speaker review not documented. |
How to cite
Helibrain (2026). Chimp test, v1. https://helibrain.com/chimp-test/methods
Changelog
· Version 1 · Initial methods publication for the current released task.
References
Inoue, S., & Matsuzawa, T. (2007). Working memory of numerals in chimpanzees. Current Biology, 17(23), R1004–R1005.
https://doi.org/10.1016/j.cub.2007.10.027original paradigm
Silberberg, A., & Kearns, D. (2009). Memory for the order of briefly presented numerals in humans as a function of practice. Animal Cognition, 12(2), 405–407.
https://doi.org/10.1007/s10071-008-0206-8practice effects in humans
Methods text: CC BY 4.0. Attribute Helibrain and link to this method. Source datasets and task material keep their own licences; this licence covers the methods text.
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