What working memory is
Working memory is the ability to hold information in mind and use it at the same moment. You rely on it when you add two prices in your head, keeping the first total while you work out the next step, or when you follow spoken directions while you are already walking.
The using is what separates it from simply storing something. In the model Alan Baddeley and Graham Hitch proposed in 1974, working memory has a speech-based part for words and digits and a visuospatial part for positions and patterns.
Why the chimp test is a good probe
Numbered squares appear at scattered positions, starting with four. You tap them in order from 1. After your first tap the remaining numbers are covered, so every other position has to be held in mind. Clear the board and the next one has one more number. A wrong tap is a strike, and three strikes end the run. Your score is the largest board you cleared.
The task asks for more than storage. You hold a set of positions, keep them in the right order, and update your place after every tap while your hand is moving. Holding and acting at once is what working memory does. Because the items are positions on a board, the task leans on the visuospatial part.
The four-chunk limit
In 1956 George Miller put the span of short-term memory at about seven items, plus or minus two. Later work suggests the capacity of working memory is closer to four chunks. A chunk is anything you treat as a single unit.
Most people clear boards of 7 to 9 numbers, which is more than four. They get there by chunking:
- Store neighbors as one cluster, such as the pair in the top left.
- Remember the route as a shape, like a zigzag or a loop.
- Split a long board into two or three short legs.
Nine positions packed into three or four chunks fit inside the limit.
Reading your score
One run tells you little. Sleep, stress and distraction all move the result, so play a few times and watch the trend on your dashboard. The full score table is on the chimp test page. For plain storage without the juggling, try the short term memory test.
This is a game, not an assessment. If you are worried about your memory, see a doctor.