He had what scientists term an autobiographical memory of the events, a type of memory that many researchers consider unique to humans. Now, a new study argues that at least two species of great apes — chimpanzees and orangutans — have a similar ability; in zoo experiments, the animals drew on 3-year-old memories to solve a problem. Their findings are the first report of such a long-lasting memory in nonhuman animals. The work supports the idea that autobiographical memory may have evolved as a problem-solving aid, but researchers caution that the type of memory system the apes used remains an open question.

 

Elephants can remember, they say, but many scientists think that animals have a very different kind of memory than our own. Many can recall details about their environment and routes they’ve traveled. But having explicit autobiographical memories of things “I” did, or remembering events that occurred in the past, or imagining those in the future—so-called mental time travel—are considered by many psychologists to be uniquely human skills.