A new Science study tests pretend play in bonobos, showing they can track pretend and real outcomes—adding to mounting evidence that ape cognition is more human-like than once assumed.
A bonobo named Kanzi sat at a wooden table in Des Moines, Iowa, faced with plastic cups and a pitcher that held—at least in appearance—imaginary juice.
The scene looked like a child’s tea party.. But Kanzi. then 44. was part of a controlled laboratory test designed to answer a deeper question: when great apes seem to “play. ” are they simply repeating learned behaviors. or are they capable of something closer to imagination—using one mental representation to stand in for another.
The work. carried out at the Ape Initiative facility in 2024 and published in Science in February. is the first empirical test to document pretend play in a great ape species.. It also arrives at a time when the cognitive study of apes has been steadily reshaping what researchers think is possible—especially around memory. social reasoning. and the ability to update beliefs when evidence changes.
In the Kanzi experiments, researchers used a verbal scaffold to keep the task understandable.. In one scenario. two cups were presented as if they contained juice: one cup was “filled. ” and the other was later “emptied” into the jug.. Kanzi was then asked to indicate which cup contained juice.. He made the correct choice in 34 of 50 trials. a result that suggests he could track a pretend beverage as a meaningful category rather than as a random object.
In another test, Kanzi faced a more direct comparison: real orange juice versus “pretend” juice.. When given the choice, he selected the cup with real juice in 14 out of 18 trials.. That difference matters.. If an ape were only responding to routine actions or sensory cues. it would be less likely to consistently distinguish between what is real and what is staged.
What’s striking is not just that Kanzi appeared to cooperate with the game.. The study is pushing toward a broader cognitive interpretation: that great apes may be able to work with “secondary representations”—mental stand-ins for situations that aren’t physically present.. In plain terms. it’s closer to thinking about an idea of a thing rather than merely reacting to the thing itself.
These findings land on top of a growing body of research that has already challenged the old boundary between human “uniqueness” and animal cognition.. Over the past decade. studies have reported long-term social memory in chimpanzees and bonobos. evidence that chimpanzees can revise beliefs when stronger information becomes available. and observations of intricate social behaviors that resemble. in function if not in form. human social cognition.. Even in cultural quirks—differences in tool use. signaling. and learned meanings—apes increasingly look less like individuals following instincts and more like members of communities with shared rules.
One of the most consequential threads in this research is the concept of theory of mind: the ability to understand that other individuals have their own beliefs and knowledge. which may differ from your own.. Researchers have been debating this capacity for years. and the trend in results has moved toward greater agreement that apes are more socially sensitive than once assumed.. The logic is straightforward: if an animal can track what others know—or how evidence changes what you should believe—then “imagination” begins to look less like a purely human possession and more like a capability that may have deep evolutionary roots.
That evolutionary framing also reframes what pretend play could mean in an ape.. Pretend behavior is sometimes dismissed as play for play’s sake.. But the Kanzi study suggests it may function as a window into how apes organize the world internally: they can treat certain cues as representing something else. and they may understand that representations can point to real consequences.. The experiment’s design—balancing pretend and real outcomes—helps separate simple mimicry from the ability to use a false or staged state as information.
There is, too, a conservation undertow.. Great apes are not only scientifically important; they are endangered across multiple regions.. As researchers probe more about their minds. the urgency intensifies: time may be running out to understand full cognitive and social diversity before habitat loss and population declines simplify what remains.
This is where research on culture becomes more than an academic detail.. If chimpanzee communities maintain distinct learned behaviors—different meanings. different tool traditions. different social rules—then losing a group can erase something that doesn’t live only in DNA.. In other words. protecting apes isn’t only about preventing extinction at the species level; it may also be about safeguarding the variety of living knowledge within species.
Misryoum readers may recognize the human parallel in everyday life.. Communities pass along “how things work” through shared routines and context—what a gesture means. how a tool is used. what counts as safe or useful.. When those communities vanish, the knowledge can disappear with them.. The idea that animals have culturally specific versions of behavior adds weight to conservation strategies that target populations rather than only numbers.
Still, one experiment cannot rewrite everything at once.. Pretend play in one bonobo, even with carefully designed tests, is a meaningful step—but it also raises new questions.. How widespread is pretend understanding among bonobos, chimpanzees, and orangutans?. Does it require particular social learning environments?. And does an ape’s ability to handle “make-believe” correlate with other capacities—like belief updating. long-term memory of social partners. or flexible reasoning under uncertainty?
As apes continue to be tested with tasks that get closer to the abstract—distinguishing real from pretend. adapting choices based on evidence strength. and tracking relationships across time—the line between “human-like” and “animal-like” keeps moving.. Kanzi’s tea party. simple on the surface. now sits inside a much bigger scientific story: that the mental lives of our closest relatives may be richer than we once thought. and that understanding them may also sharpen how we protect what remains.