New research suggests the working memory of chimpanzees operates similarly to the working memory of humans.
Several studies have detailed the impressive long-term memory of chimpanzees, but less is known about how the ape’s working memory functions.
To test chimpanzees working memories, researchers presented chimps with a lineup of small, opaque boxes. The chimps watched as food rewards were placed inside some of the boxes. To retrieve the food, chimps had to point to the box they wanted the contents of.
If the chimpanzee selected the correct box, he or she was allowed to eat the treat. After each choice, researchers hid the boxes for 15 seconds. To get all the treats, chimps had to remember which boxes they had already chosen.
Researchers increased the difficulty of the task for chimps with a knack for finding the hidden food, adding more boxes and rearranging the boxes during the 15 seconds.
The tests results — published this week in the journal Proceedings of the Royal Society B — revealed similarities between the working memories of chimps and humans.
As it does among humans, working memory differed among individual chimps. The best performing chimps were able to find four treats. One chimp remembered the location of as many as seven treats. The appearance of the boxes, as well as their positioning, helped the chimps remember where the pieces of food were hidden.RELATED Chimpanzees in West Africa observed fishing for crabs year-round
When humans are made to complete a secondary task, while conducting the memory test, their working memory suffers. Researchers observed the same phenomenon among chimps.
“Their performance decreased specifically when competing memory information was introduced,” researchers wrote in their paper. “We [also] found that individual differences in task performance were highly reliable over time. Together, these findings show remarkable similarities between human and chimpanzee.”
Previous studies have revealed the remarkable brain power of chimpanzees. One study showed chimps memorize and recall the buttocks of their friends, family, mates and enemies, the same way humans do. Chimps can even use their memory to beat humans at computer games.