Where this test comes from
This is a browser version of a famous experiment from the Primate Research Institute in Kyoto. There, chimpanzees were trained to touch numbers on a screen in order, smallest first. In the version that made headlines, the numbers vanished a split second after the first touch. The animal had to finish the sequence from memory alone. Young chimpanzees did astonishingly well even at very short viewing times. The story spread as "chimpanzees beat humans at memory".
The popular retelling flattens a lot. The chimpanzees had trained on the task for a long time. The humans they were compared with usually had not. And the viewing times that favored the chimps were extremely short. What the research really shows is narrower: a trained primate brain is very good at grabbing a quick snapshot of where numbers sit on a screen. It does not show that humans have worse memory overall. Take the name as a nod to the experiment, not a claim about you.
What it actually measures
Three things at once. That's why it feels harder than it looks.
The first is spatial working memory: the positions themselves. That much overlaps with our visual memory test, where squares light up together and you find them in any order.
The second is binding. Here, every position has a number on it, and you must keep the pair together. Not just "something was in the top right", but "the 6 was in the top right". Tying a place to a name is harder than remembering either one alone. It is where most people lose a board they thought they had.
The third is sequencing under pressure. Everything appeared at once, but you must answer in order. Every click is a small act of remembering, and mistakes snowball: hesitate on 5, and your memory of 6 and 7 keeps fading while you think.
How the board escalates
The grid stays at 5×5 throughout and the number count grows. You begin with four numbers, and every board you clear adds one more, so the difficulty comes from density, not from a bigger playing field. This matters. A fixed grid means the board always looks the same size, so a rising score means your memory improved — not that the board changed.
A wrong click costs a strike, and a fresh board of the same size appears. One mistake does not throw away the level you had reached. Three strikes ends the run, and your score is the largest board you completed, not the one you failed on.
By default you can study the numbers as long as you like — they hide when you click the 1. Two optional modes take that away. Hard hides the numbers after three seconds. Chimp gives you 0.65 seconds, the viewing time the Kyoto chimpanzees handled. Each mode keeps its own record, so a Chimp-mode score never mixes with a normal one.
Why there is no percentile here
The published research on this task studied chimpanzees. The human groups were small and tested in lab conditions a browser cannot copy: viewing times controlled to fractions of a second, fixed distance from the screen, trained participants. There is no normative human distribution for a self-paced version played on whatever screen you happen to have.
So we show your score and your own history, and no percentile at all. This is the same rule we use everywhere on this site. If a published study truly matches the task, you get a percentile and a link to it. If not, you get nothing, because the alternative is a number we made up. Most of our nine tests are in that position, and the methodology page names them.
Getting further
Do not read the numbers in order. Your instinct is to find 1, then 2, then 3. But that means scanning the board several times, and the numbers hide the moment you click 1. Instead take the whole board as one image and let the positions register together, then reconstruct the order afterwards.
Chunk by region. "Three along the top, two bottom left" is far cheaper to hold than seven separate coordinates, and it survives the moment of panic better.
Say the hard ones. If two numbers sit close together and you keep mixing them up, give them a quick silent label: "seven is the lower one". That adds word memory on top of picture memory, and two weak copies beat one.
Click deliberately. Speed buys you nothing here. Nothing here is timed. Rushing just produces misclicks on positions you actually remembered, and that costs a strike for nothing. The only clock is the decay of your own memory, and that runs at the same speed whether you hurry or not.
Finally, expect a wall somewhere between eight and twelve for most people. That is roughly where binding load exceeds what working memory holds, and pushing past it is more about strategy than effort.