Chimp Test

How to play

Numbers flash on a grid for one second, then hide behind blank squares. Tap the squares in order from 1 upward, working entirely from memory. You start with 4 numbers and every cleared level adds one more. You get 3 strikes, and each wrong tap briefly reveals the number you should have picked before the level resets.

Tips

• Read the positions as one shape, like a zigzag or triangle, instead of memorizing squares one at a time.
• Lock in 1 and 2 first. A confident start leaves more attention for the tail end of the sequence.
• A wrong tap shows you the correct square for a moment, and you replay the same level, so study the reveal.
• Most people stall at 7 to 9 numbers. Ayumu the chimp manages 9 or more, so clearing 9 earns real bragging rights.

The study behind the name

In 2007 researchers at Kyoto University published a comparison between young chimpanzees and human adults on this exact task: numbers appear on a screen, vanish behind blank squares, and the subject touches the squares in ascending order. A chimpanzee named Ayumu was faster and more accurate than the university students on the briefest exposures, which is why the test is so often quoted as one humans lose to another species.

The usual explanation is eidetic or photographic memory in young chimps, though the humans in the study had much less practice than Ayumu had. Either way the task became a standard short term memory benchmark, and this is a faithful version of it: one second of exposure, then blanks, then recall in order.

What the game is actually measuring

• Visuospatial working memory: the positions of several items held briefly and recalled in sequence. The numbers are only there to give you an order.
• It starts at 4 numbers and adds one per cleared level, so the score is the largest set you managed to hold at once. Most people plateau somewhere in the range of 7 to 9, which is also roughly the classic digit span figure.
• You get 3 strikes across the whole run. A wrong tap costs a strike and shows you the number you should have chosen, then the level restarts. The third strike ends the run, so the first two slips are recoverable and the third is not.
• Exposure is one second regardless of how many numbers there are, which is why the later levels feel like a cliff rather than a slope.

Common questions

Did chimpanzees really beat humans at this?

In the 2007 Kyoto study a young chimpanzee named Ayumu outperformed adult humans on the fastest exposures. The humans had far less practice, so the result is often overstated, but the task itself is a genuine short term memory test.

How many numbers do most people manage?

The game begins at 4 and adds one each level. Most players stall between 7 and 9, which lines up with the long established limit on how many items people hold in short term memory.

Does a wrong tap end the game?

Not on its own. You have 3 strikes for the run. A wrong tap costs one strike, briefly reveals the correct square, and restarts that level. The third strike ends the run.