Bonobos, unlike humans, are more concerned with the emotions of strangers than with individuals they know

As humans, we share many traits with bonobos. Bonobos, along with chimpanzees, are our closest ape species. Although there are many similarities in our social behavior, there are also some notable differences.

A new study from the Universities of Leiden and Amsterdam in collaboration with Apenheul shows that both bonobos and humans are more interested in homogenous photos that show emotion than neutral ones. But while our human attention is easily drawn to photos of family and friends that express certain emotions, bonobo attention is drawn to the emotions of individuals we don’t know.

Scientists like to study the behavior and other characteristics of bonobos and chimpanzees to better understand our own evolutionary history. It’s also what motivated Evy van Berlo when he decided to pursue his doctorate by looking at the evolutionary underpinnings of emotions in great apes, which are closely related to humans. research.

Van Berlo is currently working as a postdoctoral researcher at the University of Amsterdam and has completed his PhD. He studied at Leiden University. In one of her studies, together with Maris Caklett, a senior researcher at the University of Leiden, and with the help of a bonobo keeper at the Dutch zoo Apenheul, she found that bonobos and humans varied in pictures of the same species. We explored how people respond to different kinds of emotional expressions.her research results are now published in the journal emotions.

Van Berlo trained bonobos at Apenheul, a zoo dedicated to primates, to press dots on the screen. After he touched the dot, two images appeared very briefly. The images included bonobos from the same group as well as unfamiliar conspecifics. Some images were neutral, while others showed expressions and activities clearly related to emotional types such as fear, play, and sex. Then a dot reappeared behind one of these two images of him and the ape had to touch it as soon as possible.

Pressing the dot was followed by an apple-shaped reward. The system tracked how quickly the bonobos pressed dots that appeared after viewing different pictures. The idea behind this study was that apes quickly touch dots that appear behind pictures that immediately grab their attention.

“Can you react faster than a bonobo?”

Van Berlo and her colleagues conducted similar studies on humans who visited Apenheul. People were presented with the same task, with pictures of strangers or people visiting the zoo that day, and different facial expressions in the pictures (neutral, happy, scared, angry, etc.).

The challenge for human visitors was, “Can we react faster than bonobos?” We also examined reaction time here, and it was interpreted that the shorter the reaction time, the more attention was paid to the photo displayed at that moment.

“These studies confirmed that both humans and bonobos responded more quickly to homogenous photos with an emotional charge than to neutral photos,” says Van Berlo. “That’s what we expected. It makes sense given that we’re social animals. But there were also notable differences. We humans are primarily While Bonobo’s attention is focused on the study of emotional photographs of unfamiliar strangers.

difference in evolution

This finding is consistent with previous studies showing that bonobos are a so-called heterotropic animal species. Bonobos are more attracted to unfamiliar animals than to familiar conspecifics. For example, unlike humans, they will share food more quickly with unfamiliar bonobos than with individuals they know.

“Scientists suggest that this is an evolutionary difference that stems from differences in living conditions,” Van Berlo said. Under such circumstances, the need for competition with other groups and peaceful interaction with strangers may also be beneficial for species conservation. lived in nomadic groups who had to compete for food with humans from other groups. It’s beneficial.”

According to Van Berlo, it would be interesting to repeat this study in other great apes. Bonobos are known to be the most peaceful apes. Bonobos look very similar to chimpanzees, formerly called pygmy chimpanzees, but they differ greatly in social organization and behavior. Chimpanzees, for example, are much more competitive. Chimpanzee males lead the group, while bonobo females lead the group.

Van Berlo said: Individuals they know more than the feelings of strangers. ”