How does number flash memory work?
Numbers from 1 upwards appear in random squares of a 6 × 6 grid, and a bar shows how long they will stay. When it runs out they turn into blank squares, and you tap them in order from memory. You can tap 1 sooner to hide them straight away. Clear a level and the next one has one more number; a wrong tap is a strike and the level is dealt again in new places. 3 strikes end the run.
The numbers stay up for 0.6 seconds plus 0.2 seconds for each number: 1.4 seconds for the first level of 4, 2.4 seconds for 9.
How is your Number Flash Memory result calculated?
Your result is the largest level you cleared: the most numbers you tapped in the right order after they hid. Strikes and levels cleared are shown beside it. There is no score for speed, but the clock on each level means you have to take in the whole grid at a glance.
How is this different from the chimp test?
In the Chimp Test you can look for as long as you like before tapping 1. Here the numbers hide on their own, which is closer to the hardest version of the 2007 Kyoto study the chimp test is named after. Sana Inoue and Tetsuro Matsuzawa showed numerals for a moment and then covered them with white squares; with five numerals shown for 210 milliseconds, the young chimpanzee Ayumu still tapped them in order about four times in five.
Practice closes much of the gap. Ayumu had trained on the task for a long time; the students he was compared with had not. When Alan Silberberg and David Kearns gave two people practice on the same task, their accuracy matched his (Animal Cognition, 2009), and after enough practice two students tested by Peter Cook and Margaret Wilson clearly beat him (Psychonomic Bulletin & Review, 2010). Each study tested only two people, so they show what training can do, not how most people score. A short look is still hard for anyone: there's no time to rehearse the positions, only to take in the pattern.
How do you remember more numbers?
- See a shape, not a list. Take in the path from 1 onwards as one zigzag across the grid.
- Fix the start and the end. Where 1 and the last number are anchors the rest of the path.
- Tap without stopping. The picture fades fast once the numbers are gone.
For a memory of a whole pattern at once, try the Visual Memory Test; for remembering a number itself, the Digit Span Test.