Chimp Test

How to take the chimp test

1. Press Start. Four numbers appear at random positions on the grid.
2. Memorize where each number is. Take as long as you want; the clock is not running.
3. Click 1. All other numbers turn into blank squares at once.
4. Click the squares in order: 2, 3, 4 and so on. A correct square disappears; a wrong one flashes red and costs a strike.
5. Finish the round and the next one has one more number. The game ends after three strikes, and the number of squares in your last round is your score.

What the results mean

Your score is the number of squares in the last round you were playing. It measures working memory capacity for positions, the number of items you can hold at once, plus how quickly you can encode them.

The chimpanzee in the original study, Ayumu, could do 9 numbers after seeing them for 210 milliseconds, and his accuracy barely dropped when the display time was cut. People given the same task were slower and less accurate at short display times, though with unlimited time to look, as on this page, adults usually match or beat him. The point of the study was not that chimps are smarter but that young chimpanzees seem to have a very fast photographic-style memory that humans trade away for language.

The science behind the chimp test

The experiment was published in 2007 by Tetsuro Matsuzawa and Sana Inoue at the Primate Research Institute of Kyoto University. Chimpanzees were taught to touch the numerals 1 to 9 in ascending order on a touch screen. In the memory version, the numbers were replaced by white squares as soon as the first one was touched. Ayumu, then five years old, was faster and more accurate than any of the human university students tested, and his performance held up when the numbers were shown for only 210 ms, which is roughly the time of one eye movement.

Researchers link this to eidetic or photographic memory, which some young children show and which fades with age. Later work found that humans who practiced for months could approach Ayumu's scores, so the gap is partly experience. This page gives you unlimited viewing time, which makes it a test of how many positions you can hold rather than how fast you can capture them.

Tips for a higher chimp test score

Do not try to remember the numbers; remember the path. Trace a line through the squares from 1 to the last number and rehearse the shape of the line. Group the squares into chunks of three or four that form a recognisable shape (a triangle, an L, a diagonal). Keep your eyes on the next square while you click the current one, so you never lose your place. Above 10 numbers most people also benefit from saying the positions to themselves ("top left, middle, bottom right"), because it recruits verbal memory in addition to visual memory. For a pure visual version without numbers, try the visual memory test, and for a pure sequence version the sequence memory test.

Common problems and fixes

The numbers disappear before I am ready

They hide only when you click 1. Look as long as you like first; nothing is timed.

I clicked a blank square and nothing happened

Only the squares that held numbers react. Blank squares that never had a number are ignored, so a click there is neither right nor wrong.

The grid is tiny on my phone

Turn the phone sideways. The grid is 8 squares wide and uses the full width of the screen.

The game ended with lives still showing

A third strike ends the game immediately and the last heart is grayed out on the final screen. Press Start to play again.