Scientists looked at chimps and bonobos at zoos in Scotland, Japan and Belgium.
Humans are naturally adept at recognizing and remembering faces from a very young age. Newborns show a preference for looking at faces, and as they grow, this ability becomes more refined. Face recognition is often characterized by holistic processing, where the brain perceives and remembers faces as a whole rather than focusing on individual features.
While humans are known for their ability to remember people and relationships over extended periods, there has been a limited understanding of how well apes share this capacity.
A recent study published in the Proceedings of the National Academy of Sciences has unveiled intriguing findings: chimpanzees and bonobos exhibit the ability to recognize familiar faces even after being separated for up to 26 years.
Through an eye-tracking test, researchers observed that these apes devoted more time to looking at former groupmates compared to strangers, indicating a robust long-term memory for facial recognition. Notably, the duration of their gaze appeared to correlate with the quality of their previous relationships, with longer looks directed at individuals they were closer to.
These discoveries lend support to the notion that the remarkable long-term memory shared by humans, chimpanzees, and bonobos has deep evolutionary roots, possibly stemming from a common ancestor millions of years ago.
Dr Laura Lewis, the first author of the research, who is based at the University of California, Berkeley, told The Guardian, "These results represent some of the longest long-term memories ever found in nonhuman animals. It is also one of the very first studies to show that apes' memories may be shaped by their social relationships."
"It is surprising because the length and nature of this social memory is so similar to our own human long-term memory."