Bonobo’s pretend tea party shows the power of imagination

A bonobo who took part in a pretend tea party like those performed by young children showed that our closest primate relatives have the capacity to make believe.

Kanzi bonobo (Paniscus) was born in the USA in 1980 and died at the age of 44 in March of last year. He spent most of his life at the Ape Initiative in Des Moines, Iowa, where he was known for being able to communicate by pointing to symbols on a blackboard.

In the year before he died, Amálie Bastosová at the University of St Andrews in the UK and her colleagues conducted a series of experiments to understand whether Kanzi, along with his superior language skills, was also able to engage in what the researchers describe as “secondary representations”. It’s the ability to imagine an alternate reality and, in some situations, share that pretense with another individual—a skill that people develop at an early age.

By age 2 to 3, children can follow the movement of imaginary liquid between containers and see where “tea” is or isn’t, Bastos says. “That’s exactly the kind of context we presented Kanzi to test this ability on a non-human animal.

In the first phase of the experiment, the researchers pretended to pour non-existent juice into two empty cups before pretending to empty one of the cups and then asking Kanzi which one he wanted. More than two-thirds of the time, Kanzi chose a cup that was not filled and still contained the pretend juice.

“If Kanzi hadn’t invented the ‘imaginary juice’ in the cups during the study, he would have had to choose between two cups at random – after all, they were both empty,” says Bastos.

Then the scientists placed an empty cup and one with juice on the table in front of Kanzi. He chose the cup containing the juice more than three-quarters of the time. This test was to ensure that the bonobo could distinguish between real and fake juice.

For the third test, the team began by placing a real grape in one of two cups; Kanzi picked a real grape every time. A mock grape was then placed in each of the two cups before one was emptied. Again, on more than two-thirds of the trials, Kanzi correctly selected the cup that still contained the pretend grapes.

Bastos says all of the team’s studies with great apes are completely voluntary. “The fact that Kanzi stayed and continued to participate even in trials where he knew there would be no reinforcements tells me he must have at least enjoyed it a little.

Gisela Kaplan at the University of New England in Armidale, Australia, says the experiment is “unequivocally that the bonobo has understood the pretense and is coming into play.”

“This experiment is pure and simple, mimicking children’s dollhouse games, children serving each other cups of tea in small cups and pretending to drink, or offering pieces of cake that don’t exist,” he says.

Miguel Llorente at the University of Girona in Spain, describes Kanzi as “an Einstein of sorts” and now wants to understand how and why such imaginative powers emerged in the first place.

“His lifelong exposure to symbolic language and human interaction likely acted as a powerful cognitive scaffold that allowed him to externalize and refine mental tools that may remain latent in wild bonobos,” he says. “While Kanzi represents the cognitive ceiling of its species, its performance suggests that the raw biological hardware for imagination was already present in our common ancestor 6 to 9 million years ago.”

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