Kanzi the bonobo’s unwavering performance in simulated play experiments strongly indicates that the cognitive faculty for conceptualizing absent entities possibly dates back 6 to 9 million years, thereby necessitating a recalibration of prevailing notions regarding the singularity of human imagination.
Kanzi the bonobo. Image credit: Ape Initiative.
“The revelation that their cognitive existences extend beyond immediate temporal and spatial realities is truly a paradigm shift,” remarked Dr. Christopher Krupenye, a researcher affiliated with Johns Hopkins University.
“While imagination has long been regarded as a cornerstone of human identity, the proposition that it may not be exclusively confined to our species presents a profoundly transformative perspective.”
“The groundbreaking discoveries by Jane Goodall concerning tool fabrication by chimpanzees fundamentally altered the definition of what it means to be human. Similarly, this current research compels us to re-examine distinctions that define our uniqueness and to contemplate the richness of consciousness present in other sentient beings.”
By the age of two, human youngsters are adept at engaging in imaginative scenarios, such as staged tea gatherings.
Even infants as young as 15 months exhibit measurable surprise when observing an individual simulate the act of ‘drinking’ from a receptacle after ostensibly emptying its contents.
Prior to this investigation, a dearth of rigorously controlled studies had examined pretense behaviors in nonhuman primates, notwithstanding a variety of anecdotal accounts depicting animals seemingly engaging in pretend actions, both in their natural habitats and in controlled environments.
For instance, instances have been documented in the wild wherein juvenile female chimpanzees have been observed cradling and interacting with sticks, mimicking the maternal gestures of cradling their offspring.
Furthermore, a captive chimpanzee exhibited behavior suggestive of manipulating non-existent blocks on the floor, following a period of engagement with tangible wooden blocks.
Drs. Krupenye and Amalia Bastos, his colleague from the University of St. Andrews, embarked on a quest to ascertain if this capacity for pretense could be rigorously evaluated within a controlled experimental framework.
They devised a series of experiments bearing significant resemblance to a child’s pretend tea party, designed to assess Kanzi, a 43-year-old bonobo (Pan paniscus) residing at Ape Initiative, who had a history of anecdotal reports of pretense and demonstrated an ability to respond to verbal cues through pointing.
In each experimental session, an investigator and Kanzi were positioned opposite each other, tea party-style, at a table furnished with either unadorned pitchers and cups or bowls and jars.
The initial task involved two transparent receptacles, both devoid of content, placed alongside an empty transparent pitcher.
The experimenter simulated the act of decanting a small quantity of imaginary beverage into each cup, subsequently enacting the emptying of one cup, accompanied by a subtle shaking motion to emphasize the removal of any residual liquid. The experimenter then posed the query, “Where’s the juice?”
Kanzi consistently indicated the correct receptacle that still conceptually held the simulated beverage with remarkable accuracy, even when the position of the ‘juice’-containing cup was altered.
To rule out the possibility that Kanzi perceived the presence of actual liquid within the cup, even if it were visually imperceptible, the researchers conducted a supplementary experiment.
This subsequent trial featured a cup containing genuine juice juxtaposed with the cup holding the pretend beverage.
When queried about his preference, Kanzi invariably gestured towards the real juice.
A third experimental iteration mirrored the approach of the second, substituting grapes for liquid.
An experimenter feigned tasting from an empty container before placing a simulated grape within one of two jars.
The experimenter then mimicked emptying one of the containers and inquired, “Where’s the grape?” Kanzi again accurately identified the locus of the non-existent fruit.
While Kanzi’s responses were not infallible, his accuracy remained consistently high.
“The data provide compelling evidence, which is both striking and immensely gratifying, suggesting that apes possess the cognitive capacity to conceptualize entities that are not physically present,” stated Dr. Bastos.
“Kanzi demonstrates an aptitude for generating a mental representation of a hypothetical object while simultaneously maintaining an awareness of its non-actual status.”
“Imagination is intrinsically linked to the cultivation of a rich internal mental landscape in human beings,” commented Dr. Krupenye.
“Should the evolutionary origins of imagination share commonality with nonhuman primates, it should prompt a critical re-evaluation of the assumption that other species lead purely instinctual lives, rigidly bound to the present moment.”
“These findings should galvanize us to extend greater consideration and protection to these creatures possessing complex and beautiful minds, ensuring their continued existence.”
The research endeavor is published this day in the esteemed journal Science.
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Amalia P.M. Bastos et al. 2026. Evidence for representation of pretend objects by Kanzi, a language-trained bonobo. Science 391 (6785): 583-586; doi: 10.1126/science.adz0743
