The Bonobo Who Played Pretend: Why Kanzi’s Imaginary Tea Party Changes Everything
1. Introduction: The Universal Language of "As If"
Imagine a two-year-old child sitting on a miniature chair, carefully tipping an empty teapot over a plastic cup. They offer a "sip" to a stuffed bear, wait a beat, and then "drink" some themselves. To us, this is the charming, mundane magic of a toddler's first tea party—the birth of the "as if." For decades, evolutionary psychologists believed this ability to decouple mental ideas from reality—a framework known as "secondary representation"—was the final boundary between humans and the rest of the animal kingdom. We assumed our cousins were locked in a "robotic" existence, strictly responding to the physical here-and-now.
However, a groundbreaking study published in the journal Science in February 2026 has shattered this anthropocentric boundary. The research centers on Kanzi, a world-famous bonobo (Pan paniscus) who became a bridge between our species and his own. This discovery carries a poignant weight: Kanzi died in March 2025 at the age of 44. This final study, published posthumously, serves as his parting gift to science—a profound demonstration that the spark of imagination is a legacy shared by the entire Pan-human clade.
2. The Invisible Pour: Tracking Things That Aren't There
The evidence for this cognitive leap comes from a series of "juice party" experiments designed by comparative psychologists Amalia Bastos and Christopher Krupenye. Sitting across from Kanzi at a table with two empty, transparent cups, a researcher took a see-through, empty jug and "poured" pretend juice into both. The researcher then "emptied" one of the cups back into the jug and asked Kanzi: "Where is the juice?"
Kanzi did not point at random. Across multiple trials, he correctly identified the cup that should contain the "pretend juice" 68% of the time, a result significantly higher than chance. To ensure this wasn't a fluke, researchers replicated the logic using "pretend grapes" placed into jars, where Kanzi again successfully tracked the imaginary solids. These tasks require the mind to generate a stable internal representation of an object that has no physical presence—a high-level cognitive feat once thought unique to human development.
"Kanzi is able to generate an idea of this pretend object and at the same time know it’s not real," notes Amalia Bastos, now at the University of St Andrews.
3. Reality Check: Distinguishing the Real from the Make-Believe
A critical question in animal cognition is whether a subject is truly "imagining" or simply confused by the experimental setup. To rule out the possibility that Kanzi’s aging vision led him to believe the cups held real liquid, the team conducted a "reality check." Kanzi was presented with a choice: a cup of actual orange juice versus an empty cup that researchers only pretended to fill.
Kanzi chose the real juice nearly 80% of the time. This data is vital as it proves "dual representation"—the ability to hold a pretend scenario in mind without losing a grip on reality. He knew the imaginary juice was a game, but he preferred the tangible reward.
However, the findings have met with some professional rigor. Biologist Daniel Povinelli of the University of Louisiana at Lafayette suggests a more skeptical interpretation: perhaps Kanzi was simply tracking the "recency of touch," pointing to the cup the researcher had interacted with last. While the "reality check" helps mitigate this, the debate underscores the difficulty of peering into a non-human mind.
4. Mind Reading 101: Tracking Human Ignorance
Imagination is the bedrock of "Theory of Mind"—the ability to understand that others have different knowledge states than our own. In a landmark study published in PNAS in early 2025, lead author Luke Townrow and Christopher Krupenye tested this by asking Kanzi and his relatives, Nyota and Teco, to help a human find a hidden treat.
The methodology revealed a startling level of strategic thinking. When the bonobos knew the human had seen the treat being hidden, they often sat still during a 10-second wait period, knowing the partner required no help. But when the human was "ignorant"—having been looking away when the treat was moved—the bonobos pointed to the correct cup almost immediately. They were holding two conflicting worldviews: their own knowledge of the treat’s location and the partner’s lack of it.
"Imagination has long been seen as a critical element of what it is to be human, but the idea that it may not be exclusive to our species is really transformative," says Christopher Krupenye. "It really is game-changing that their mental lives go beyond the here and now."
5. The 6-Million-Year-Old Spark: Rethinking Evolution
Because these traits—imagination and the tracking of ignorance—are present in both humans and the genus Pan, we must conclude they are ancestral. This suggests the capacity for secondary representation likely dates back 6 to 9 million years to the common ancestor we shared before our lineages split.
We must, however, consider the "enculturation" factor. Kanzi was an "Einstein of bonobos," raised in a human environment and proficient in over 380 lexigram symbols. As evolutionary anthropologist Alexander Piel notes, we are still untangling whether these abilities are "natural" or if human scaffolding unlocked latent potential. It remains unclear if wild bonobos in the Democratic Republic of Congo—currently endangered by poaching and deforestation—exercise these same "as if" muscles in their daily lives.
6. Imagination as the Engine of Invention
Acknowledging imagination changes how we interpret physical survival strategies like tool use. If an animal can play pretend, then tool use is likely not just accidental discovery, but proactive mental simulation. To create a stone flake, Kanzi had to visualize the sharp edge before it existed.
Yet, skepticism remains. Duke University’s Michael Tomasello argues that to be fully convinced of true internal pretense, he would need to see Kanzi initiate the pour himself, rather than just responding to human-led play. Nevertheless, the link between make-believe and invention is becoming harder to ignore.
"You can’t invent a bicycle if you can’t imagine one first," says Cathal O’Madagain of the University of Mohammad VI Polytechnic.
7. Conclusion: Beyond the Robot Lifestyle
The legacy of Kanzi’s tea party marks a paradigm shift. It forces us to retire the "robotic" model of animal behavior and acknowledge the existence of "rich and beautiful minds" in our closest relatives. If a bonobo can track an invisible pour and wait for an ignorant human to catch up, they are existing in a world far more cognitively complex than we previously dared to imagine.
As we reflect on Kanzi’s life and his final scientific contributions, we are left with an ethical imperative. If bonobos possess an internal world that mirrors the vivid imagination of a human child, how does that change our responsibility to protect the few thousand that remain in the wild? We are not alone in the world of "as if"; we are simply the ones with the power to decide if that world continues to exist for our cousins.
