How Pretend Play Works—and Why Apes Do It Too

The Cognitive Power of Make-Believe

When a child pours invisible tea for a stuffed bear, something remarkable is happening inside their brain. They are holding two versions of reality simultaneously—one where the cup is empty and one where it brims with imaginary liquid. This ability, called pretend play, requires the mind to represent objects and scenarios that do not physically exist, then act on those representations as though they were real.

For decades, scientists classified this skill as uniquely human. No other species, the thinking went, possessed the cognitive architecture to imagine what isn't there. That assumption was upended in February 2026, when a study published in Science demonstrated that a bonobo named Kanzi could track and reason about pretend objects—passing the first controlled test of imagination in a nonhuman animal.

What Pretend Play Actually Requires

Pretend play is far more cognitively demanding than it appears. It rests on several interlocking mental abilities:

• Symbolic representation—treating one thing (a banana) as if it were another (a telephone)
• Counterfactual reasoning—entertaining a scenario the player knows to be false
• Theory of mind—understanding that another person shares the pretend framework
• Executive function—inhibiting the impulse to treat the pretend world as literal

In humans, pretend play emerges around age two, peaks between ages three and five, and continues into middle childhood. Research from the Child Mind Institute shows it strengthens language development, emotional regulation, and abstract thinking—skills that form the scaffolding for later academic and social success.

The Bonobo Breakthrough

The 2026 study, led by comparative psychologist Amalia Bastos of the University of St Andrews and Christopher Krupenye of Johns Hopkins University, put Kanzi through a series of carefully designed "tea party" experiments at the Ape Initiative in Des Moines, Iowa.

In the first test, a researcher placed two empty transparent cups on a table, then pretended to pour juice from an empty pitcher into both. After "emptying" one cup back into the pitcher, the researcher asked Kanzi: "Where's the juice?" Kanzi consistently pointed to the cup that still held the imaginary liquid.

A second experiment offered a choice between a cup of real juice and one containing only pretend juice. Kanzi chose the real juice roughly 78% of the time—demonstrating he could distinguish between actual and imagined contents. According to the Johns Hopkins University report, these results indicate Kanzi was genuinely representing invisible objects in his mind, not simply following behavioural cues.

Rewriting the Timeline of Imagination

The implications stretch far beyond one clever bonobo. If bonobos share the cognitive machinery for pretend play, that machinery likely existed in the last common ancestor of humans and great apes, which lived six to nine million years ago. Imagination, in other words, may be far older than our species.

Anecdotal evidence had hinted at this for years. Wild chimpanzees in Uganda were observed carrying sticks and cradling them like infants—behaviour that resembled doll play. Captive chimpanzees appeared to drag imaginary blocks across the floor after playing with real wooden ones. But until the Science study, no controlled experiment had confirmed that apes could mentally represent objects that were not physically present.

Why It Matters Beyond the Lab

Understanding the evolutionary roots of imagination has practical consequences. In child development, decades of research confirm that pretend play builds inhibitory control, cognitive flexibility, and task persistence—the executive functions that predict school readiness. If these capacities share deep evolutionary origins with other primates, scientists may gain new tools for studying how they develop and what happens when they don't.

For animal cognition research, the findings open new questions. Can other great apes—gorillas, orangutans—also pass pretend-play tests? Does imagination exist in more distant relatives like monkeys or corvids? And what does the presence of make-believe in nonhuman minds tell us about the boundary between animal and human thought?

The empty teacup on a laboratory table may seem like a simple prop. But what a bonobo sees in it—or imagines in it—is reshaping how science understands the origins of the human mind.