Bonobos, Our Closest Animal Relatives, Like Bullies And Jerks

Bonobos, who live only in the Democratic Republic of Congo, are endangered and their numbers are dwindling. Bonobos and chimpanzees are our closest relatives. Wandering Panda on Flickr

If you saw someone helping another person, then a third person antagonizing them, who would you choose to associate with? As a human, chances are you'd prefer the helper, who appears to be a more cooperative member of society. But, according to new research out of Duke University, not all apes feel the same way.

A study published today in the journal Current Biology demonstrated that bonobos, who, along with chimps, are humans' closest relatives, actually prefer bullies who harass and hinder others.

This research was inspired by similar studies on humans. In 2007, scientists published a finding on human infants between the ages of six and nine months old. The study found that, even before they even learned to talk, the babies were able to figure out who around them was helpful and who was antagonistic. Then, in behavioral tests, the infants demonstrated that they preferred the helpers. The results were replicated in 2011.

"This led to the hypothesis that this could be a fundamental aspect of human interactions, accounting for some of our more sophisticated cooperative behavior," Christopher Krupenye, one of the authors on the new bonobo paper, told Newsweek. Krupenye is a postdoctoral researcher in developmental and comparative psychology at the Max Planck Institute in Germany.

The authors of the new paper wanted to test this hypothesis and see whether our closest ape relatives would also prefer social, helpful individuals. The would indicate the preference is common, if not inherent, among all apes.

To test their hypothesis, the scientists studied bonobos at Lola Ya Bonobo Sanctuary. They showed them cartoons of simple shapes either helping another shape up a hill, or blocking them and pushing them downward. They also showed a person holding a teddy bear and dropping it, a "helper" picking up the bear and returning it, and a "hinderer" stealing the bear.

When offered a slice of apple from the helpers and the hinderers, or when the slices were placed under paper cutouts of the helpful and unhelpful shapes, bonobos generally showed preference for the jerks.

This preference is surprising considering that bonobos are seen as peaceful creatures, or even "hippie chimps." The researchers chose to study bonobos as opposed to chimpanzees because bonobos are more socially cooperative, especially in settings where food is involved.

However, Krupenye calls their reputation as lovers and not fighters "overblown." They still fight and live in a society of dominance, which could explain why they prefer the more unhelpful, or controlling, individuals.

"For them, dominance is really important," Krupenye said. "We think that they are seeing the hinderer as the dominant individual because the individual blocks someone else's goal."

Humans may be distinct from bonobos in our preference for helpers, however, we don't know if our appreciation of nice behavior is a unique trait to humanity that developed recently, or if the bonobos evolved their preference independently. A similar study on other apes could help answer that question, and if we could go back in time, on our common ancestor as well.