Chimp Test
Numbers appear on a grid. Tap 1 and the rest hide; tap them in order, from memory. Each round adds a number, until they slip. A chimp beats most humans at this.
The ladder
Bar widths show roughly how many people land in each band on the provisional curve. Your number is the most numbers you cleared in one round. Round one deals four; they stay on the grid until you tap 1, then the rest hide and you tap them in order; every round cleared adds one; a wrong tap costs one of three strikes and deals the same count again; the third strike ends the run.
What moves it
Places, not numbers. The order is given; only the places are yours to hold. Read the grid as a path, 1 to 2 to 3, and walk it; a path of nine turns is held far more easily than nine spots.
Take your time before 1. Nothing is timed while the numbers show. Every second spent looking is free; every second after the tap on 1 is memory draining. Look until the path is yours, then tap.
Strikes are a budget. Three wrong taps for the whole run, not per round, and a strike deals the same count again. A guess at seven is paid for at twelve; when a place is uncertain, a slow look before 1 is cheaper than a strike after it.
What this measures
In 2007, researchers at Kyoto University's Primate Research Institute published a result that still stings: young chimpanzees, trained to touch numerals in order, held the positions of digits flashed for a fraction of a second better than the adult humans tested beside them. The task became famous as the chimp test, and what it measures is spatial working memory: not the numbers, which are printed, but where each one sits.
Round one deals four numbers. Study them as long as you like, nothing is timed; tap 1 and the rest go blank, then tap the blanks in order. A cleared round deals one more number. A wrong tap costs one of three strikes for the whole run and re-deals the same count on a fresh layout, so a slip earns a second look at the same difficulty rather than a demotion, and the third strike ends the run.
The winning move is to read the grid as a path, 1 to 2 to 3, and walk it back: nine turns of one path hold far more easily than nine loose positions. Why the chimps win anyway, and what their win says about what human memory traded away, is in the memory guide; the curve's pedigree is on the Method page.
Questions people ask
It is the most numbers you cleared in one round. Round one deals four; every round you clear adds one. A wrong tap costs a strike and ends the round, and the same count is dealt again on a new layout; the third strike ends the run, and the round you were on does not count. Nothing else is scored: the strikes and the pace are on the card, but they do not move the number.
After the chimpanzees of Kyoto University's Primate Research Institute, who learned this task on a touch screen: in a 2007 study, young chimpanzees held the places of numerals that had shown for a fraction of a second, and beat the adult humans tested alongside them. This version keeps the rule and drops the timer: the numbers stay until you tap 1, which is how most people meet the test online.
Nobody has measured it properly, so the curve here is a guess, re-centered on Human Benchmark's saved scores and shifted down one for self-selection: 9 is the middle, 11 is a big round, 14 is rare. The numbers stay as long as you like, and the order is printed on them, so expect to land above your digit span. The curve is an assumption until humanlag has its own runs.
Because one rule beats two. The classic online version gives three strikes for the run too, and so does our visual memory test; one budget fits in a sentence and makes every guess cost the same wherever it lands. A strike deals the same count again, so a slip is a second look, not a demotion.
Ayumu, the star of the Kyoto experiments, placed numerals he had seen for as little as a fifth of a second; this version lets you study the board for as long as you like before touching 1. The two tasks share a rule but not a difficulty, so a big round here out-holds this site's pool, not the chimpanzee. Try forming the path in under a second sometime: that is the game Ayumu was playing, and it is humbling.
It starts as an assumption worth 1000 runs, shaped from published norms, and every run played here adds one to it, everyone in one pool. The Method page says which norms, how the percentile is read, and how many runs this test has measured so far.