Planet of the Apes: Koko the Gorilla Demonstrates Great Apes' Capacity for Speech

Friday, 14 August 2015 - 1:04PM
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Friday, 14 August 2015 - 1:04PM
Planet of the Apes: Koko the Gorilla Demonstrates Great Apes' Capacity for Speech
Koko the Gorilla, who is best known for her ability to meaningfully communicate with humans using a form of American Sign Language, has consistently demonstrated our underestimation of the intelligence of great apes. Now, researchers who work closely with her have discovered that she may have capacity for speech, which would make apes the only animal other than humans with that particular skill.

Koko has spent her entire life in captivity, living immersed among humans for more than forty years. She interacts with her human caretakers, psychologist Penny Patterson and biologist Ron Cohn, for hours each day, and through sign language has given valuable insight into apes' complex inner lives. Researcher Marcus Perlman started working with Koko in 2010, with the intention of studying her gestures and movements, but after studying 71 hours of video, discovered that she may be capable of a form of vocal speech.

Opening quote
"Decades ago, in the 1930s and '40s, a couple of husband-and-wife teams of psychologists tried to raise chimpanzees as much as possible like human children and teach them to speak. Their efforts were deemed a total failure," Perlman told UW News. "Since then, there is an idea that apes are not able to voluntarily control their vocalizations or even their breathing."
Closing quote


Apes do make vocal sounds, but after these failed experiments, they were thought to be entirely reflexive in response to stimuli from their environment, such as the sudden appearance of a predator or a mating call. Human speech is distinctive, as the thought goes, because we are able to control it and learn new sounds.

Opening quote
"This idea says there's nothing that apes can do that is remotely similar to speech," said Perlman. "And, therefore, speech essentially evolved - completely new - along the human line since our last common ancestor with chimpanzees."
Closing quote


But now, in a new study published in Animal Cognition, Perlman and co-author Nathaniel Clark analyzed nine different vocal behaviors that indicated Koko's control over her breathing and vocalizations. She was seen blowing her nose into a tissue, playing wind instruments, breathing condensation onto glasses to clean them, blowing a raspberry into her hand to indicate that she wanted a treat, and imitating phone conversations by vocalizing into a telephone.







While these behaviors aren't exactly speech, they do demonstrate that we have been erroneous in assuming that apes are definitely incapable of speech.

Opening quote
"She doesn't produce a pretty, periodic sound when she performs these behaviors, like we do when we speak," said Perlman. "But she can control her larynx enough to produce a controlled grunting sound."
Closing quote


Not only do the behaviors show that she is able to control her breathing, but they also show that she's been able to learn from her human companions. As a result, it stands to reason that any ape could be capable of speech-like behaviors if they lived with humans for long enough.

Opening quote
"Presumably, she is no more gifted than other gorillas," he said. "The difference is just her environmental circumstances. You obviously don't see things like this in wild populations."
Closing quote


Koko may actually give biologists more insight into the evolution of speech, as her behavior demonstrates that our ability to speak may have begun to evolve with gorillas.

Opening quote
"Koko bridges a gap," said Perlman. "She shows the potential under the right environmental conditions for apes to develop quite a bit of flexible control over their vocal tract. It's not as fine as human control, but it is certainly control."
Closing quote


Koko first came to prominence in the media in 1984, when she famously mourned the loss of her pet kitten:



And if that wasn't enough sadness for you, she also reportedly mourned the loss of her good friend Robin Williams, who passed away a year ago this week:

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