Like Humans, Chimpanzees and Orangutans Remember Distant Past Events

Humans and apes share a lot in common. We can solve problems, express emotions and use tools. Now, researchers have discovered something else that we have in common; we can both remember events that happened years in the past.

In order to examine whether chimpanzees and orangutans could remember distant past events, researchers set up a tool-finding event. The apes had to search for tools and the location of a tool that they had seen only once before. After testing the animals, the researchers found that the apes were able to remember where to look after having experienced this scenario just four times about three years earlier.

"Our data and other emerging evidence keep challenging the idea of non-human animals being stuck in time," said Gema Martin-Ordas of Aarhus University in a news release. "We show not only that chimpanzee and orangutans remember events that happened two weeks or three years ago, but also that they can remember them even when they are not expecting to have to recall those events at a later time."

The chimpanzees and orangutans weren't just able to remember the past events, though. They were also able to distinguish between similar past events in which the same tasks, locations and people were involved. When presented with a particular setup, the apes instantaneously remembered where to search for the tools and the location of the tool. They were also able to perform the task quickly. On average, it took the animals just five seconds to go and find the tools.

"This is a crucial finding since it implies that our subjects were able to bind the different elements of very similar events-including task, tool, experimenter," said Martin-Ordas. "This idea of 'binding' has been considered to be a crucial component of autobiographical memories."

The new research not only shows a little bit more about chimpanzees and orangutans. The findings also have implications for new research on memories for past events. It's possible that non-human animals may be able to recall far more than we first thought.

The findings are published in the journal Currently Biology.