Bonobos May Understand Pretend Scenarios and Track Imaginary Objects, Study Suggests
Recent research published in the journal Science suggests that bonobos may possess the capacity to understand pretend scenarios and track imaginary objects. The study, co-authored by Dr. Amalia Bastos from the University of St Andrews and Dr. Christopher Krupenye from Johns Hopkins University, focused on a bonobo named Kanzi, who died at age 44.
Research Focus and Subject Background
The investigation aimed to determine if Kanzi, a bonobo known for communicating with graphic symbols and creating simple stone tools, could engage in pretend play. Pretend play is defined in the study context as acting as if something is real while understanding that it is not. Kanzi had been raised in a laboratory setting. Previous observations in other great apes included chimpanzees holding sticks as if they were infants and captive chimpanzees simulating play with imaginary blocks.
Experimental Design and Findings
The research involved three primary experiments designed to test Kanzi's engagement with imaginary concepts:
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Imaginary Juice Test: Kanzi was presented with two empty transparent cups. Researchers simulated filling one cup with an empty jug and then 'emptied' the imaginary contents from that cup back into the jug. When asked to identify the cup containing juice, Kanzi selected the 'full' cup in 34 out of 50 trials, equating to 68% accuracy. This outcome exceeded chance levels and occurred without the provision of rewards for correct selections.
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Real vs. Imaginary Juice Distinction: To assess if Kanzi differentiated between tangible and imaginary liquids, he was offered one cup containing real juice and one empty cup, into which researchers then pretended to pour juice. Kanzi chose the cup with real liquid in 14 out of 18 trials, indicating an ability to distinguish between actual and simulated substances. This represented an almost 80% selection rate for real juice.
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Imaginary Grape Test: In a third experiment, researchers placed an imaginary grape into one of two transparent containers. Kanzi successfully identified the container holding the imaginary grape.
Kanzi's 68% accuracy in identifying the 'full' cup in the Imaginary Juice Test exceeded chance levels and occurred without rewards, providing early evidence of his ability to track imaginary objects.
Implications and Expert Perspectives
Researchers suggest that the ability for make-believe may have roots deep in human evolutionary history, potentially tracing back to a common ancestor shared with bonobos an estimated 6 to 9 million years ago. The study provides experimental evidence indicating that a non-human animal can track imaginary objects within pretend scenarios, implying that the capacity to represent pretend objects is not exclusive to humans.
Dr. Krupenye stated the work suggests imagination's roots are not exclusive to humans.
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 added that further work is necessary with apes not extensively trained for human communication, noting that it is not surprising for close living relatives to exhibit advanced cognitive abilities similar to humans.
Conversely, Michael Tomasello, a comparative psychologist at Duke University, expressed skepticism, highlighting the distinction between envisioning an action and maintaining pretense. Tomasello indicated that his conviction would require observing Kanzi initiate the pouring of imaginary water.
Limitations and Future Research
The study acknowledges challenges inherent in determining the cognitive processes of apes concerning the abstract nature of imagination, including the possibilities of imitation or confusion between real and imaginary objects. Kanzi's unique upbringing in a human-centric laboratory environment raises questions about whether his demonstrated abilities are specific to his individual context or representative of broader ape capabilities. Researchers, including Dr. Bastos, noted that Kanzi's case establishes a foundation for future studies, particularly for understanding the cognitive capacities of endangered great ape species in wild environments.