Humans can remember events that happened years ago, with those memories often surfacing unexpectedly in response to sensory triggers like flavor or scent. Now, new evidence suggests that chimpanzees and orangutans have similar capacities. (Credit: © mrahmo / Fotolia) Enlarge

July 18, 2013 — We humans can remember events in our lives that happened years ago, with those memories often surfacing unexpectedly in response to sensory triggers: perhaps a unique flavor or scent. Now, researchers reporting in Current Biology, a Cell Press publication, on July 18 have evidence to suggest that chimpanzees and orangutans have similar capacities. In laboratory tests, both primate species were clearly able to recollect a tool-finding event that they had experienced just four times three years earlier and a singular event from two weeks before, the researchers show.

It seems we have more in common with our primate cousins than we thought, specifically when it comes to our autobiographical memories, the researchers say.

"Our data and other emerging evidence keep challenging the idea of non-human animals being stuck in time," says Gema Martin-Ordas of Aarhus University in Denmark. "We show not only that chimpanzees 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 in the study could also distinguish between similar past events in which the same tasks, locations, and people were involved, she adds. "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. This idea of 'binding' has been considered to be a crucial component of autobiographical memories."

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