CEFR Level: B2 (Upper-Intermediate)

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Bonobo’s Pretend Play Challenges Assumptions About Human Uniqueness

February 2026 — A study published in the prestigious journal Science has presented compelling evidence that a bonobo named Kanzi possesses the cognitive capacity for imaginative pretend play—an ability long considered exclusively human.

Beyond the Here and Now

Researchers from Johns Hopkins University designed three rigorous experiments to investigate whether great apes can engage in what psychologists call “secondary representation”: the ability to simultaneously hold in mind both reality and an imagined alternative. This cognitive skill allows human children to host tea parties with empty cups while fully understanding no actual tea exists.

“It really is game-changing that their mental lives go beyond the here and now,” explained co-author Christopher Krupenye. “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.”

The Experimental Design

Kanzi, a 43-year-old bonobo residing at the Ape Initiative, served as the primary subject. Unlike wild apes, Kanzi has been “enculturated”—raised in close proximity to humans—and can respond to verbal prompts using a lexigram system comprising over 300 symbols.

In the initial experiment, researchers placed two empty transparent cups before Kanzi. They proceeded to pantomime pouring juice from an empty pitcher into one cup, then pretended to pour the imaginary juice back into the pitcher. When prompted to identify where the juice was located, Kanzi selected the correct cup 68 percent of the time—significantly above the 50 percent expected by random chance.

A crucial follow-up experiment addressed potential skepticism. Researchers offered Kanzi a choice between a cup with real juice and one with only imaginary juice. Kanzi chose the real juice nearly 78 percent of the time, demonstrating clear discrimination between reality and pretense.

Implications for Cognitive Science

The findings challenge long-held assumptions about the boundaries of animal cognition. Previous observations of apes appearing to engage in pretend behaviors had been dismissed as responses to behavioral cues rather than evidence of genuine imagination.

“Kanzi is able to generate an idea of this pretend object and at the same time know it’s not real,” noted co-author Amalia Bastos, now at the University of St. Andrews. The researchers acknowledge that future studies must determine whether these abilities extend to apes without Kanzi’s extensive human cultural exposure.

The discovery follows in the footsteps of Jane Goodall’s revolutionary observation that chimpanzees use tools—a finding that fundamentally altered our definition of what it means to be human.

Vocabulary Help

• cognitive capacity = mental ability to think, learn, and understand
• secondary representation = holding two mental states (real and imagined) simultaneously
• enculturated = raised within a human cultural environment
• pantomime = to express or act out something without using words
• discrimination = the ability to recognize differences between things

Grammar Focus

• Complex passive constructions: “An ability long considered exclusively human”
• Present participles as adjectives: “The compelling evidence” / “The rigorous experiments”
• Reporting structures: “Researchers noted that…” / “The study demonstrated that…”