Research has found that bonobos behave differently based on whether they perceive the presence or absence of information in others. This discovery overturns the conventional belief that the ability to detect knowledge gaps exists only in humans.
A research team from the Johns Hopkins University in the United States noted on the 3rd (local time) that primates can sense the ignorance of others. The findings were published in the Proceedings of the National Academy of Sciences (PNAS).
The research team conducted an experiment to observe the behavior of bonobos, which varies according to human knowledge. In an experiment involving three bonobos, one researcher first hid a snack (grapes or cereal) under one of three cups. At this time, the researcher sitting across from the bonobo sometimes saw where the snack was hidden, while at other times they did not. The researcher then asked the bonobo, "Where is the snack?" and waited for 10 seconds.
The experiment revealed that when the researcher sitting opposite the bonobo witnessed the process of hiding the snack, the bonobo simply sat still and waited. In contrast, when the researcher did not see the process of hiding the snack, the bonobo pointed to the cup that hid the snack. One bonobo even tapped the cup multiple times to attract the researcher's attention.
Chris Krupenny, a professor of psychology and neuroscience at Johns Hopkins University, said, "Not only humans but also primates possess rich cognitive abilities in common," adding, "This ability suggests the possibility that humans and primates evolved from a common ancestor."
Numerous studies have shown that primates possess empathy and social bonding abilities similar to humans. Erica Cartmill, a professor at the University of California, Los Angeles (UCLA), observed the process of primates playing with peers and building social bonds. Professor Cartmill explained, "Play is a behavior that builds social bonds among peers, which is accompanied by expressions such as vocalizations and facial expressions," and added, "The behavior observed this time aimed to provoke or tease another peer unilaterally."
Italian researchers discovered in 1990 that monkeys exhibited the same neural activity by observing the behavior of other peers or humans without any special actions. This neural activity later became known as "mirror neurons," and it is known that all primates possess these mirror neurons.
Heo Jae-won, director of the National Primate Research Center, said, "While humans have been considered communicators as collaborators, chimpanzees were thought to communicate as competitors, but this study shows that not all primates behave that way."
Reference material
Proceedings of the National Academy of Sciences (PNAS) (2025), DOI: https://doi.org/10.1073/pnas.2412450122
Proceedings of the Royal Society B (2024), DOI: https://doi.org/10.1098/rspb.2023.2345