Monkeys remembered events and faces 25 years ago: no worse than people

The animal chose a familiar face from two photographs.

Apes may have amazing memories. Animals can recognize old friends even after more than a quarter of a century, a new study claims. Scientists showed primates images of old acquaintances and noted their reactions

A new study shows that great apes have better memory than some humans. Scientists studied a group of great apes; when the animals were shown photographs of old friends – some of whom they had not seen for more than 25 years – the apes reacted to the photographs.

The study was published in the journal Proceedings of the National Academy of Sciences. Lead author Dr. Laura Lewis of the University of California, Berkeley, told Fox News that the animals are actually very similar to humans.

“We tend to think of great apes as something completely different from ourselves, but we actually saw that these animals have cognitive mechanisms that are very similar to our own, including memory,” she noted.

The team of researchers worked with chimpanzees and bonobos at three zoos – Edinburgh Zoo in Scotland, Plankendael Zoo in Belgium and Kumamoto Nature Reserve in Japan, Fox News reports. The scientists collected photographs of monkeys that are no longer at the zoo and have not been seen by other monkeys for at least nine months to 26 years.

One of the goals was to find out what kind of relationship the animals had and whether they would have any positive or negative feelings associated with these memories.

The monkeys were shown two photographs side by side—one of a monkey they had met before and one of an unfamiliar animal. The researchers then used an eye-tracking device to measure where the monkeys looked and for how long.

The team found that the animals tended to look longer at the familiar image than at the second photo. The primates also focused their gaze more on those with whom they had had positive relationships in the past.

The researchers were most interested in a bonobo monkey named Louise, who was shown an image of her sister and nephew she had not seen in more than 26 years. She looked at them both with “astonishing confidence” in eight separate comparisons, according to the scientists.

The author of the study, Lewis, believes that in this way we can come to the conclusion that the memory power of these animals is similar to that of humans.

“This pattern of social relationships shaping long-term memory in chimpanzees and bonobos is similar to what we see in humans: our own social relationships also appear to shape our long-term memory of individuals,” she explains.

Dr Lewis adds: “The idea that they actually remember others and therefore might miss fellow humans is actually a powerful cognitive mechanism and something that was thought to be uniquely human.”

Laura Lewis points out that the study “raises questions about the possibility that they may have the capacity to become bored.”