Autumn and Winter Check-in Challenge
A new study has found that apes — our closest living relatives — can recognize family and long-lost friends even after decades of separation.
Researchers tested 26 captive chimpanzees and bonobos from zoos around the world, showing them former group mates and unknown apes, conclusively confirming long-held primatologists' suspicions.
Laura Simone Lewis, a postdoctoral fellow in the Berkeley Department of Psychology and lead author of the study, explains: "It's a very simple test: Do they look at their previous companion for a longer period of time, or do they look at strangers for a longer period of time”。
We found that, yes, they looked at their former peers for significantly longer periods of time. ”
According to a report published last week in the Proceedings of the National Academy of Sciences, there is also evidence that they become more focused when they see an ape's ** than in a hostile relationship.
"As human beings, we like to think of ourselves as unique and special creatures, with incredible intelligence that is very different from other animals on the planet," Lewis said. ”。This study shows us how similar we are to chimpanzees and bonobos.
She noted that the findings support a theory that the long-term social memory of humans, modern chimpanzees and bonobos evolved from "our last common ancestor, who lived between 5 million and 7 million years ago," and that these ancestors may also have long-term social memory.
How researchers conduct experiments
The participating apes were volunteers, drinking juice while staring at the screen flashing side-by-side of other bonobos and chimpanzees**. One of the animals in each pair has lived with the group for at least a year, while the other is a stranger. An infrared eye-tracking camera recorded the participants' gaze and duration. The data shows that their gaze stays on their familiar companions longer, suggesting that they "have a wealth of recognition for each other."
In the most impressive case, a 46-year-old bonobo named Louise in Japan's Kumamoto Reserve repeatedly showed "intense" attention when she saw her sister Loretta and nephew Erin's **, two men she hadn't seen in 26 years. The team said Louise's findings represent the longest-lasting social memory of any non-human animal to date.
Senior author Christopher Krupeenye, an assistant professor at Johns Hopkins University who studies animal cognition, said the experiment was inspired by long-term observations by primatologists who visit individual animals they study every few months or years.
"When [great apes] see a familiar face, especially one they haven't seen in a long time, they get excited," Krupenye said. It seems that they really recognize and remember us. We wanted to design a study that could test this. ”。
Krupeenye says they now have evidence that apes remember individuals most of the time of their average lifespan of 40 to 60 years. This makes their memory comparable to that of humans, and according to the study, their memory begins to decline after 15 years, but can persist for up to 48 years after separation.
Now that they have conclusive evidence that the memories of these endangered species rival those of humans, dolphins, elephants and ravens, the researchers have more questions, including whether the apes miss those who are no longer with them, especially their friends and family.
"They do remember other people, so they may miss them, and it's a powerful cognitive mechanism that is thought to be something unique to humans," Lewis said. ”。Our research doesn't determine for sure that they are doing so, but it raises questions about the likelihood that they are capable of doing so. ”