Bonobos can spot bozos: Apes can tell when humans act stupid, says study

Researchers tested if apes could exercise “theory of mind” and found that they can tell if someone is ignorant and will leap to bridge the knowledge gap, a first.

Chris Krupenye, the study’s co-author, explained that our ability to recognize when others lack knowledge is key to our most advanced social behaviors.

This cognitive process, known as “theory of mind,” enables humans to “cooperate, communicate, and work together strategically.”

However, whether nonhuman primates possess this ability had been debated for decades—until now, as new findings suggest they can even warn others of potential danger.

Apes know when you don’t know something

Krupenye and co-author Luke Townrow, a Johns Hopkins Ph.D. student, replicated their behavior in the wild for the first time in a controlled setting by conducting a “seemingly simple experiment” with three bonobos sheltered at Ape Initiative: Teco, Nyota, and Kanzi.

Far from rudimentary, however, “theory of mind supports many of the capacities that make humans unique, like teaching and language,” Krupenye explained. For the first time, their exercise demonstrated that apes perform this “seemingly simple” mental process.

Once familiar with the objective, the bonobos understood that they would get a treat if Townrow found it. The grape or Cheerio was hidden under one of three cups, so “where is it?” He asked them.

Sometimes, it was obvious that Townrow knew where it was; other times, he wasn’t privy to that information. Depending on his knowledge set, the apes reacted differently. When he knew, they didn’t respond. In the case that he hadn’t seen where Krupenye had placed the treat, they jumped in.

“Their fingers would point right through the mesh—it was clear what they were trying to communicate,” Krupenye said. They were able to detect ignorance, and when their partners lacked knowledge, they pointed more often and more quickly, Krupenye mentioned.

The experiment furthermore suggests that apes can “simultaneously hold two conflicting world views in their mind. They know exactly where the food is, and at the same time, they know that their partner’s view of the same situation is missing that information.”

But how do they think about someone else’s mind?

Some called the experiment “contrived.” Regardless, it revealed that apes do possess “theory of mind,” suggesting that “these abilities evolved millions of years ago in our common ancestors.”

Next, the team plans to delve deeper how apes think about one another’s mind.

“What we’ve shown here is that apes will communicate with a partner to change their behavior, but a key open question for further research is whether apes are also pointing to change their partner’s mental state or their beliefs,” Townrow concludes.

The study was published in the journal Proceedings of the National Academy of Sciences.