Can you do better than a chimp?

In this test, boxes will appear at different locations on the screen, each containing a number. Try to remember which number appears in which box. After a short time, the numbers will disappear. Now, click the boxes in numerical sequence, beginning with the box that contained 1, then 2, and so on.

If you are correct, the next problem will have one more box to remember. If you make an error, then the next problem will have one fewer box to remember. After 3 errors, the test will end.

## Optimizing Performance

In this test:

- Accuracy does matter; after three errors, the test ends. However, wrong answers do not subtract from your score, which is the maximum number of boxes you can correctly remember.
- Speed does not matter; the numbers appear quickly, but you have as long as you'd like to answer. It might be hard to remember if you wait too long though!

So to get maximum points, pay careful attention when you are shown the location of each number, and reach the largest number of boxes you can possibly remember.

*Video instructions*

## Domain Scores

Your score on this test contributes to:

- Your
*short-term memory*score (a lot). - Your
*reasoning*score (a bit).

The contribution of each test to each performance category is based on a "factor analysis" that looked at how tests tend to clump together when measuring a massive set of data. The results were published in *Neuron* in 2012 (Hampshire, Highfield, Parkin, & Owen, 2012). The exact contribution of each test to each performance category may change as more data is collected.

## Monkey Ladder in the Real World

Viewing a situation, planning a sequence of moves, then executing them from memory, is essential in many everyday tasks. It would be especially useful when planning a sequence of branches to grab while swinging through trees—maybe that's why apes are so good at it! Here is a video of Ayumu the chimp doing very well at Monkey Ladder:

## References

- Cook, P., & Wilson, M. (2010). Do young chimpanzees have extraordinary working memory?
*Psychonomic Bulletin & Review, 17,*599-600. - Inoue, S., & Matsuzawa, T. (2007). Working memory of numerals in chimpanzees.
*Current Biology, 17,*R1004-R1005. - Silberberg, A., & Kearns, D. (2009). Memory for the order of briefly presented numerals in humans as a function of practice.
*Animal Cognition, 12,*405-407.