Chimp Test
Numbers appear scattered on a grid. The instant you click 1, the rest go blank — click them in order from memory. Clear the board and it grows by one. Three strikes ends the run.
Chimp Test
Click the numbers in order. After you click 1, the rest turn blank — remember where they were. Three strikes ends the run. Chimps average 9.
This task is famous because of Ayumu, a chimpanzee at Kyoto University's Primate Research Institute who reliably beat university students at it — young chimps appear to have a photographic-like buffer for spatial snapshots that adult humans largely traded away (one hypothesis: for language). Most people plateau around 8–10 numbers. The human workaround is the same as the other memory tests: encode the shape of the first few numbers as a path, snapshot the stragglers, and click briskly — the spatial trace decays fast, so hesitation is the real enemy here.