Bonobos are next to the chimpanzees our closest relatives. However, while chimpanzees are often quite aggressive towards their conspecifics, the bonobos are considered particularly peaceful. According to the motto: "Make Love Not War" they solve their conflicts through sex rather than fighting. Studies also show that the bonobos willingly help each other and even share their food with other species. "So many see the bonobos as the hippies among the apes, " says first author Christopher Krupenye of Duke University in Durham. "They cooperate to an extent that we do not know so much about chimpanzees." But how far does the social streak of the bonobos go? Do you also rate your conspecifics according to how cooperative they are?
Helper or Hinderer?
In our case, three-month-old babies already show a pronounced preference for helpful people: they instinctively turn to the people they were previously able to observe, how they helped another human being. On the other hand, if you see a person harming another person, avoid them. However, whether this behavior is typically human or whether our closest relatives share it with us has been unclear. In search of an answer, Krupenye and his colleague Brian Hare have now tested bonobos in an Orphaned Monkey Guard in the Democratic Republic of the Congo.
For their experiment, they first showed 24 bonobos a short film in which an abstract figure helped another one up a mountain. A second figure pushed her partner down the slope. Subsequently, the great apes should choose between paper representations of these two figures. In a second test, the bonobos watched a man steal a cuddly toy from a second. A second person, on the other hand, turned out to be a helper and returned the beast to the victim. Again, the researchers wanted to know which person would prefer the apes. Would they react just like human children?
Clear preference for the asocial
The surprising result: The bonobos showed with their reactions that they can clearly distinguish between helpful and anti-social behavior. "But they did not demonstrate a preference for the helpers, " report Krupenye and Hare. "Instead, in all cases, they chose the 'bad guys' - those who thwarted the other's goals." This reaction surprised even the two primate researchers. "That was amazing and totally unexpected, " says Krupenye. But the bonobos were not deterred and demonstrated in other variants of this test again and again their preference for anti-social louts. display
"These experiments show that humans and bonobo show very different preferences in almost identical situations - despite their close relationship, " the researchers say. In her view, this might indicate that the instinctive preference for social conspecifics is indeed a typically human trait - and only developed in the course of human evolution. "Apparently, these preferences are closely linked to the particularly cooperative nature of humans, " the researchers said. They may even have been crucial to mankind's ability to train such complex social structures and societies.
Why, however, do the bonobos, despite their high social intelligence, prefer the buggers? Krupenye and Hare suggest that this is related to the pronounced sense of rank and dominance of these great apes. An indication of this was provided by another test. In this, the researchers showed the bonobos videos in which a figure was constantly pushing to a particularly coveted place and drove all the others out - she behaved so dominant. On the other hand, another readily gave up the place. The reaction of the great apes was clear: they preferred the more unsocial but dominant figure. The researchers suspect that this behavior benefits the bonobos in their everyday social life: it pays off for them if they get on well with dominant species.
- Christopher Krupenye and Brian Hare (Duke University, Durham), Current Biology, doi: 10.1016 / j.cub.2017.11.061