Bonobo Imagination: Kanzi Demonstrates Pretend Play in Tea Party Experiments

Overview

In a Science Friday segment, host Kathleen Davis discusses with cognitive scientist Amalia Bastos a study on Kanzi the bonobo and his ability to participate in pretend play. The team replicated a classic child-psychology tea party paradigm, using two empty glasses and imaginary juice to test whether Kanzi could track imaginary displacements. Through careful controls and naive experimenters, the researchers demonstrated that Kanzi pointed to the juice-containing container more often than chance, indicating a grasp of pretend scenarios. They also ran a follow-up test with real versus fake juice to rule out confusion. The discussion touches on the evolutionary value of imagination and Kanzi's lasting impact on the field.

Introduction and Context

Science Friday hosts a conversation about imagination beyond humans, prompted by a bonobo named Kanzi. Kathleen Davis, the show’s sci fi producer, explains that Kanzi could engage with symbols on lexigrams to request interactions like tickling and chasing, inspiring a deeper look into whether nonhuman primates can participate in pretend play. Amalia Bastos, a cognitive scientist at the University of St Andrews, describes how the idea for the study emerged from Kanzi's own behaviors and his communication with researchers. The aim was to test whether imitation of pretend scenarios requires imagination or can be explained by simple cue-following.

"Kanzi pointed at me, and pointed at one of the symbols on his lexigram" - Kathleen Davis

Experimental Design and Rigor

The researchers adapted a well-known child literature paradigm to bonobos. Kanzi was presented with two glasses and imaginary juice, and researchers asked him to indicate which glass contained the imaginary liquid. The team used a naive experimental setup: the data collectors did not know the hypotheses, and the pouring was performed by trained researchers rather than the experimenters themselves. Bastos notes that this design reduces the risk of experimental bias and strengthens the claim that Kanzi engaged with pretend play rather than simply following cues. A follow-up experiment replaced the pretend juice with real and fake juice to verify perceptual distinctions; Kanzi could tell the difference, showing that the task relied on imagination rather than misperception.

"the people actually collecting the data didn't know what was expected of Kanzi" - Kathleen Davis

Findings and Implications

Kanzi pointed to the correct, imaginary-juice glass more often than would be expected by chance, supporting the claim that he tracked the displacement of imaginary objects. Bastos and colleagues emphasize that this does not prove Kanzi hosted his own tea party, but it does show a capacity to imagine and monitor imaginary events orchestrated by humans. The team also discusses limitations, such as Kanzi's encultured background and the challenge of eliciting pretend play without direct reinforcement. The discussion broadens to consider whether imagination could be present in other species and the evolutionary benefits it might confer, particularly in preparing for future situations without real risk.

"pretending is a way to prepare you for the future without any real risks" - Amalia Bastos

Broader Reflections and Future Directions

The interview closes with reflections on humanity's self-perceived uniqueness. The researchers highlight how new findings continually reshape our understanding of what makes humans special, illustrating how discoveries about animal cognition challenge long-held assumptions. Bastos notes that Kanzi's death in 2025 marks a poignant moment for the field, underscoring the emotional connection researchers develop with highly studied individuals. The conversation ends with a nod to Kanzi's legacy and the possibility of applying innovative methods to test imagination in less enculturated species.

"Kanzi understood that there was a tea party happening, and he's playing pretend" - Amalia Bastos