Scientists discover bonobos can imagine, challenging what we know about animal minds

Scientists at Johns Hopkins University have discovered something unexpected in a series of experiments with a bonobo named Kanzi: the ability to imagine things that are not there. The findings, published this week, suggest that imagination may not be the exclusive domain of humans after all, and could reshape how researchers understand animal minds.

Kanzi, a 43-year-old bonobo living at Ape Initiative, sat across a table from researchers in a series of experiments designed to mimic children's pretend tea parties. The results showed that Kanzi could track imaginary juice and pretend grapes, consistently pointing to the correct locations of objects that existed only in the scenario the researchers had created.

Background

Kanzi is no ordinary bonobo. He was raised in a human environment from birth and has spent decades learning to communicate with people. He uses a lexigram board, a keyboard-like device with symbols, to respond to spoken questions by pointing. This background made him an ideal candidate for experiments that required understanding abstract concepts.

Researchers Christopher Krupenye and others at Johns Hopkins noticed something intriguing during an early interaction with Kanzi. When they pretended to chase each other, Kanzi watched and seemed to enjoy the performance even though no one was actually running. This observation sparked an idea: could Kanzi understand pretend play?

The team decided to design a series of controlled experiments to test whether Kanzi could genuinely imagine objects or whether he was simply following visual cues from the researchers' actions.

Key Details

The Juice Experiment

In the first test, an experimenter sat across from Kanzi with two empty transparent cups and an empty pitcher. The experimenter pretended to pour juice from the pitcher into both cups, then acted out dumping the juice from one cup back into the pitcher while shaking it to show it was empty. The experimenter then asked Kanzi, "Where's the juice?"

Kanzi pointed to the cup that was supposed to contain the pretend juice 68 percent of the time, well above what would be expected by chance. Even when the experimenter moved the cups around, Kanzi continued to point to the correct one.

But the researchers needed to rule out an alternative explanation: maybe Kanzi simply believed real juice was hidden in the cup. So they ran a second test. This time, one cup contained actual orange juice and the other held pretend juice created through the same pouring motions. When asked which cup he wanted, Kanzi picked the real juice nearly 80 percent of the time.

"It's extremely striking and very exciting that the data seem to suggest that apes, in their minds, can conceive of things that are not there," one researcher said. "Kanzi is able to generate an idea of this pretend object and at the same time know it's not real."

The Grape Experiment

The researchers repeated the process with grapes. An experimenter pretended to take a grape from an empty container and placed it into one of two jars. After pretending to empty one jar, the experimenter asked, "Where's the grape?" Kanzi indicated the jar holding the pretend object, demonstrating he could apply the same imaginative thinking to different scenarios.

Kanzi did not respond correctly every single time, but his answers were reliably accurate across the trials.

What This Means

The findings challenge the long-held scientific assumption that imagination is unique to humans. Researchers have long believed that the ability to conceive of things that do not exist, to hold abstract ideas in the mind, separated humans from other animals. These experiments suggest that distinction may not be as clear as once thought.

The research also raises important questions about animal cognition more broadly. If bonobos can imagine, what about other apes? What about other species? Researchers plan to explore whether other bonobos and apes without Kanzi's extensive training and human-raised background can also pass these tests.

The work builds on decades of research showing that great apes have surprising cognitive abilities. Previous studies have shown they can use tools, understand cause and effect, and demonstrate self-awareness. But the ability to imagine things that do not exist represents a different kind of thinking, one that requires holding multiple representations in mind at once.

For scientists studying animal minds, the implications are significant. It suggests that the gap between human and animal intelligence may be smaller than previously believed, and that abilities once thought to be uniquely human may have deeper evolutionary roots. As researchers continue this work, they may find that imagination, like many other traits, exists on a spectrum across the animal kingdom rather than being a sharp dividing line between humans and everything else.