Apes imagine tea party scenes in lab experiments, scientists say

Researchers in Baltimore staged a series of whimsical “tea party” experiments and came away with evidence that at least some apes can imagine and play pretend. The findings, published in the journal Science, challenge the long-standing idea that imaginative play is a uniquely human trait.

At the center of the study was Kanzi, a 43-year-old bonobo known for unusual cognitive skills. Across controlled tasks, Kanzi treated invisible juice and grapes as real objects and reliably indicated their locations after a researcher pretended to pour or move them — suggesting he understood both the idea of a pretend object and its unreality.

What the tea-party tests actually showed about ape imagination

Scientists designed childlike scenarios to ask a simple question: can an ape form a mental representation of something that isn’t physically present? The experiments produced consistent behavior from Kanzi that points to the answer being yes.

• Pretend pouring: The researcher mimed pouring juice from a clear pitcher into two empty clear cups, then pretended to empty one cup. When asked where the juice remained, Kanzi pointed to the correct cup even after cup positions were swapped.
• Real vs. pretend choice: To rule out the idea that Kanzi was simply guessing where hidden liquid might be, the team presented a real cup of juice alongside a cup that only contained pretend juice. When offered a choice, Kanzi almost always selected the real juice.
• Pretend grape task: In a third setup, a researcher pretended to taste a grape and then moved an imaginary grape into one of two jars. Kanzi again indicated the jar he believed contained the pretend fruit more often than not.

How the study was built to avoid mistakes and bias

The researchers took steps to make sure the results reflected true understanding of pretense, not clever cue-reading or confusion about real versus imagined objects. They used transparent containers so Kanzi could see there was nothing physically present, varied the positions of items, and introduced real items alongside pretend ones to measure preferences.

Control features that mattered

• Visible empty containers, eliminating hidden-object explanations.
• Position swaps to prevent location-based guessing.
• Real-object trials to measure whether the ape could distinguish tangible rewards from pretend ones.

These controls strengthen the claim that the bonobo was representing the pretend object mentally rather than reacting to visible cues or prior training.

Context: how this fits with earlier observations of animal play

Ethologists and zookeepers have long reported behaviors that look like pretense among primates: young chimpanzees carrying sticks like dolls, captive apes miming the movement of imaginary blocks, and other playful actions that suggest an inner life. Until now, however, controlled experiments explicitly testing pretend representation were absent.

This study provides the first robust experimental evidence that a nonhuman primate can hold an idea of an object that isn’t actually there, and can distinguish that idea from reality.

Why researchers say the result is important for how we think about cognition

The implications reach into evolution and ethics. If imagination — the ability to create and manipulate mental representations of absent things — is shared with our closest relatives, its roots may extend back to the common ancestor of humans and apes several million years ago. That reframes imagination as an evolutionary continuity rather than a purely human innovation.

Scientists involved in the research note that imagining is a cornerstone of human mental life, linked to play, planning, empathy, and creative problem-solving. Finding precursors of that capacity in apes invites fresh questions about animal minds and how we value them.

Who took part and why Kanzi matters

Kanzi lives at the Ape Initiative, a sanctuary and research center devoted to bonobo study and conservation. He has a documented history of complex behavior and responsiveness to verbal cues, making him an ideal subject for a first controlled test of pretense.

• Age and background: Kanzi is an older bonobo with a history of interactive training and research participation.
• Behavioral record: Previous anecdotal reports suggested he sometimes engaged in pretend-like actions, which led researchers to formalize tests.

What’s next: questions the team plans to tackle

Researchers say this is only a starting point. Their next steps include expanding tests to other apes and species, and probing other forms of imagination — for instance, whether apes can envision future events, simulate possible outcomes, or infer what another individual might be thinking.

• Replicating the paradigm with more individuals and species.
• Exploring temporal imagination — the ability to imagine future scenarios.
• Investigating theory of mind capacities tied to pretend play.

The study encourages a rethink of assumptions that nonhuman animals live only in the immediate present and lack richly structured mental lives. If elements of imagination are shared across primates, both scientific understanding and conservation approaches may shift to reflect the deeper cognitive lives of these animals.

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Michael Thompson

Michael Thompson is an experienced journalist covering U.S. and global news. With ten years on the front lines, he breaks down political and economic stories that matter. His precise writing and keen attention to detail help you grasp the real‑world impact of every event.