A Helpful Friend

Bonobos are able to tell when a human doesn’t know something and help them find their way, a new study shows.

Johns Hopkins University researchers Chris Krupenye and Luke Townrow conducted an experiment with three male bonobos to determine the ape’s “theory of mind” – described as the ability to understand the mental state of others.

“(This) ability to sense gaps in one another’s knowledge is at the heart of our most sophisticated social behaviors, central to the ways we cooperate, communicate, and work together strategically,” Krupenye explained in a statement. “Because this so-called theory of mind supports many of the capacities that make humans unique, like teaching and language, many believe it is absent from animals.”

For their experiment, Townrow sat across a table with one bonobo, while a second person placed a treat under one of three cups. While the apes would watch as the experimenter placed the treat, Townrow would sometimes see where it was hidden, and other times he couldn’t.

After asking, “Where’s the grape,” the researcher waited 10 seconds before choosing a cup. If Townrow had seen the hiding place, the bonobo remained still.

But if he hadn’t, the animal actively pointed to the correct cup – sometimes emphatically.

“Their fingers would point right through the mesh – it was clear what they were trying to communicate,” said Krupenye.

One bonobo, Kanzi, was especially demonstrative: He would tap on the mesh insistently to direct Townrow to the right cup.

The team explained that the findings showed that the ape species recognized when someone lacked knowledge and acted to help.

Their behavior also suggested that the creatures held two conflicting perspectives at once: They knew where the food was and also understood that their human partner did not.

The study aligns with previous research on wild chimpanzees that vocalize warnings when members of their group are unaware of nearby threats, according to Scientific American.

It also shows that this theory of mind ability might date to the last common ancestors of humans and bonobos that lived millions of years ago.

The authors are hoping to explore new insights into this ability, such as whether the apes recognize the mental state of ignorance and if they understand they are changing a human’s knowledge.