Great apes can tell when someone else has a false belief

Great apes can tell when someone else has a false belief

Great apes may be even more like us than we thought. We already knew that they can understand someone else’s goals, intentions and desires. However, scientists have long believed that they lack the capacity for understanding what others believe — a mark of advanced social cognition thought to separate people from great apes. But now new research overturns this belief.

“Social cognition is the sum of cognitive abilities necessary to survive in a social world,” says David Buttelmann of the Max Planck Institute for Evolutionary Anthropology in Germany. “Whenever individuals interact, they need to understand the gestures, motivations, feelings, intentions, and beliefs of their partners.”

Using a test developed for human infants, Buttelmann and his colleagues assessed whether chimpanzees, bonobos and orangutans could understand whether someone else’s beliefs were true or false. The researchers recently reported their findings in PLOS ONE.

First a person put an object in one of two boxes. Then a second person switched the object to the other box and locked both boxes.

For the “true belief” test, the first person watched the switch — so he knew where the object was and thus had a true belief.

For the “false belief” test, however, he left the room during the switch — so while he thought he knew where the object was, he was mistaken and thus had a false belief.

In both cases, the person then tried to open the box where he had originally put the object. And the apes, who knew how to unlock the boxes, could decide which one to open.

The researchers found that, like human infants, great apes were more likely to help the person find the object when he had a false belief about where it was. This suggests the apes used their understanding of his beliefs about reality to decide whether to help him.

Buttelmann says great apes enjoy the beliefs test, which is voluntary; “They only play with us if they are in the mood, so we have to present them with interesting games.”

Now he wants to extend this work to other animals. “I would love to develop interactive false-belief tests for other species,” Buttelmann says. “This way we will be able to track the development of our own mind and understand, at some point, what made us uniquely human.”

Research Article: Buttelmann D, Buttelmann F, Carpenter M, Call J, Tomasello M (2017) Great apes distinguish true from false beliefs in an interactive helping task. PLoS ONE 12(4): e0173793. doi:10.1371/journal.pone.0173793

Image Credit: Buttelmann et al (2017)


Robin is a freelance science writer based in the San Francisco Bay Area, covering water, energy and the environment in the western US, and all things biology from biomechanics to behavior.

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