It means that chimpanzees also depend on complex social learning behaviour. And that while this was previously regarded by many as something uniquely human.

People learn to use tools and other skills by copying others. This form of social learning has made human culture increasingly complex. Some argue that this so-called “cumulative culture” is something uniquely human. But a new study of chimpanzees proves otherwise.

Study

In a long-running experiment, researchers supplied a group of wild chimpanzees in the Mount Nimba nature reserve — located on the border of Guinea, Liberia and Ivory Coast — with piles of nuts and stone tools. Precisely these tools are used by a neighboring chimpanzee population to crack nuts. But do the chimpanzees in the experiment understand what to do with them? Can wild chimpanzees invent complex behaviors like cracking nuts?

A chimpanzee uses stone tools to crack a nut. Image: Kathelijne Koops, UZH

The answer to that question is no. Despite showing curiosity, the Nimba group failed to crack open the nuts even after a year. So it seems that chimpanzees don’t instinctively know what to do when they come across nuts and rocks. To crack open the nuts, they probably need to learn how from peers.

Chimpanzee Culture

The findings provide further insight into the nature of chimpanzee culture. Nut cracking is considered a cultural behavior that only certain groups do. The experiments suggest that chimpanzees who have never seen a congener crack a nut, at least are not so quick to think of it themselves. Not even if they are given the necessary tools. “They really have to be taught how to crack nuts,” says researcher Kathelijne Koops. “They seem incapable of inventing the use of tools themselves.” An example figure from whom they can copy seems to be the missing puzzle piece in the experiments.

social learning

According to the researchers, this indicates that chimpanzees also depend on complex social learning behaviour. They should disregard other people’s use of tools, just like people. It means that chimpanzees most likely also have a ‘cumulative culture’ that relies on social learning. And that while this was previously regarded by many as something uniquely human.

It means that chimpanzee culture is much more like our own culture than previously thought. “Our findings on wild chimpanzees — our closest relatives — help shed light on what makes our human culture (and not!) unique,” Koops said. “In particular, the results suggest a similar cultural evolution. The human capacity for our cumulative culture may have shared evolutionary origins with chimpanzees.”