Bonobos May Share Human Capacity for Make-Believe, Study Suggests
Groundbreaking Research Challenges Exclusivity of Imagination to Humans
A recent study published in the journal Science suggests that bonobos may possess the cognitive capacity to understand pretend scenarios and track imaginary objects. The research, conducted by scientists including Dr. Amalia Bastos from the University of St Andrews and Dr. Christopher Krupenye from Johns Hopkins University, involved experiments with a bonobo named Kanzi. This work challenges the notion that the ability for make-believe is exclusive to humans.
Kanzi: A Bonobo with Advanced Cognitive Abilities
The subject of the study was Kanzi, a male bonobo known for his advanced cognitive abilities. Kanzi was raised in a laboratory setting and was recognized for communicating with humans using graphic symbols and demonstrating the creation of simple stone tools. He died last year at the age of 44.
Researchers adapted developmental psychology studies typically conducted with children to assess Kanzi's understanding of pretend play.
Experimental Design and Key Findings
The study involved three primary experiments conducted at the Ape Initiative in Des Moines, Iowa:
The Imaginary Juice Test
In the first experiment, Kanzi was presented with two empty transparent cups. Researchers simulated pouring imaginary juice into one cup from an empty jug, then pretended to empty the contents of one cup back into the jug.
When asked to identify the cup containing the imaginary juice, Kanzi selected the 'full' cup in approximately 68-70% of trials (34 out of 50 in one report). This occurred without rewards for correct answers.
Distinguishing Real vs. Imaginary Juice
To assess whether Kanzi differentiated between real and imaginary substances, he was presented with one cup containing actual juice and another empty cup where researchers pretended to pour imaginary juice.
Kanzi chose the cup with real liquid in 14 out of 18 trials, indicating an ability to distinguish between tangible and imaginary substances.
The Imaginary Grape Test
In a third experiment, Kanzi was able to identify the location of an imaginary grape that researchers had pretended to place in one of two transparent containers. He correctly identified the location in 68.9% of trials, reportedly performing faster than in the juice experiment.
Interpretations: Deep Roots of Imagination
Researchers concluded that these findings provide experimental evidence that a non-human animal can track imaginary objects in pretend scenarios, suggesting that the capacity for representing pretend objects is not exclusive to humans.
They propose that the ability for make-believe may have roots deep in human evolutionary history, potentially tracing back to a common ancestor shared with bonobos approximately 6 to 9 million years ago.
Professor Zanna Clay of Durham University, who was not involved in the research, commented that the study offers a rigorous experimental test for a form of imaginative thinking in apes. She noted, however, that further work is needed with apes not extensively trained for human communication.
Kristin Andrews, a philosophy professor at City University of New York, stated that Kanzi demonstrated pretense and imagination, which involves holding a non-real version of the world in mind, a skill that can enhance choice-making abilities. Primate behavioral ecologist Nicholas E. Newton-Fisher observed that the experimental evidence supports previous anecdotal reports of imagination in both captive and wild apes.
Limitations and Future Directions
Some skepticism was expressed by Michael Tomasello, a comparative psychologist at Duke University, who noted a distinction between envisioning an action and maintaining pretense. He suggested he would require observation of Kanzi initiating the pouring of imaginary water to be convinced.
The study acknowledged that Kanzi's unique background, including extensive human interaction and language training, raises questions about whether his abilities are specific to his environment or indicative of broader ape capabilities.
While the study involved only one bonobo, researchers suggest the findings may extend beyond Kanzi given existing anecdotal evidence of similar behaviors in other apes. Further investigation is recommended to generalize these results to other great ape species, particularly those in the wild, to understand the full scope of their cognitive capacities.