In a set of carefully designed experiments modeled on children’s tea parties, researchers at Johns Hopkins University found that an ape could engage in pretend play. The results mark the first controlled demonstration that an ape can imagine objects that are not actually there, a skill long considered uniquely human.

Across three separate tests, the bonobo interacted with invisible juice and imaginary grapes in a consistent and reliable way. The performance challenges longstanding assumptions about the limits of animal cognition.

The researchers conclude that the ability to understand pretend objects falls within the mental capacities of at least one enculturated ape. They suggest this ability could trace back 6 to 9 million years to a common ancestor shared by humans and other apes.

Ape Imagination Upends Human Uniqueness in Science Study
“It really is game-changing that their mental lives go beyond the here and now,” said co-author Christopher Krupenye, a Johns Hopkins assistant professor in the Department of Psychological and Brain Sciences who studies how animals think. “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.

“Jane Goodall discovered that chimps make tools, and that led to a change in the definition of what it means to be human, and this, too, really invites us to reconsider what makes us special and what mental life is out there among other creatures.”