Orangutan’s Mimes Understand Other’s Perceptions

Photo via flickr by guppiecat

Sorting through 20 years of orangutan behavior observed in Indonesia, two researchers have discovered in 18 occasions what they interpret as orangutans acting out a request or other communication in elaborated gestures of pantomime, beyond their demonstrated miming used to communicate. The observations may offer insight into what orangutans understand about the minds of others and also shed light on the ancient gestural roots of human language.

On four of the occasions, one orangutan mimed for another, and 14 instances an orangutan mimed to a human, according to a paper released online the week of August 9 in Biology Letters.

One example of miming a need to a human occurred in a free-living forest facility on Borneo, where orangutans sometimes get dirt scrubbed off their faces by a person with a leaf. According to study coauthor and cognitive ecologist Anne Russon of York University in Toronto, a young male called Cecep plopped down in front of her and handed her a leaf.

“I played dumb,” she remembers. “He waited a respectable few seconds, then — all the while looking me in the eye — he took back the leaf, rubbed it on his own forehead….” Again he handed it to her. “Then I did as I was told,” she says, and wiped away the dirt.

Orangutan-to-human pantomimes may be the easiest to observe, Russon says, but these occasions may also present special challenges to communication, and possibly to patience. “The orangutans get a look on their faces like ‘Are you stupid?’” she says.

In another occasion caught on video (see below), Russon says a young female orangutan called Siti swiftly punched though one of a coconut’s three eyelike depressions and broke off a leaf stem to fish out the sweet innards. When Siti had exhausted what she could reach through that opening, she took her coconut to one of the men at the rehabilitation forest who did whack open coconuts with his big parang knife, but he handed the nut back to Siti.

She “briefly and weakly poked into the coconut opening” and then handed it back to the human. When the man again did nothing, Siti took her leaf stem and made chopping-style slashes against the coconut, in what looked to Russon like mimicry of a person using a parang.

One of the themes in 13 of Russon’s examples is the mimer’s elaboration of a breakdown in communications. This “suggests they understand something about what their partner didn’t understand,” she says.

Studying mime offers a way to look at long-standing issues of nonhuman species’ theories of mind. Pantomime gestures also present a way to look at the deep evolutionary origins of human language, Russon says. Recent thinking has raised the possibility that language sprouted from gestural communication.

via Science News

A young orangutan pantomimes for help with a coconut from Science News on Vimeo.

Video credit: Courtesy of A. Russon

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