Apes may be closer to speaking than many scientists think

Mountain gorilla
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Koko the gorilla is best known for a lifelong study to teach her a silent form of communication, American Sign Language. But some of the simple sounds she has learned may change the perception that humans are the only primates with the capacity for speech.

In 2010, Marcus Perlman started research work at The Gorilla Foundation, where Koko has spent more than 40 years living immersed with humans—interacting for many hours each day with psychologist Penny Patterson and biologist Ron Cohn.

"I went there with the idea of studying Koko's gestures, but as I got into watching videos of her, I saw her performing all these amazing vocal behaviors," says Perlman, now a postdoctoral researcher in the lab of University of Wisconsin-Madison psychology Professor Gary Lupyan.

The vocal and breathing behaviors Koko had developed were not necessarily supposed to be possible.

"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 says. "Since then, there is an idea that apes are not able to voluntarily control their vocalizations or even their breathing."

Instead, the thinking went, the calls apes make pop out almost reflexively in response to their environment—the appearance of a dangerous snake, for example.

And the particular vocal repertoire of each ape species was thought to be fixed. They didn't really have the ability to learn new vocal and breathing-related behaviors.

These limits fit a theory on the evolution of language, that the human ability to speak is entirely unique among the nonhuman primate species still around today.

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

However, in a study published online in July in the journal Animal Cognition, Perlman and collaborator Nathaniel Clark of the University of California, Santa Cruz, sifted 71 hours of video of Koko interacting with Patterson and Cohn and others, and found repeated examples of Koko performing nine different, voluntary behaviors that required control over her vocalization and breathing. These were learned behaviors, not part of the typical gorilla repertoire.

Among other things, Perlman and Clark watched Koko blow a raspberry (or blow into her hand) when she wanted a treat, blow her nose into a tissue, play wind instruments, huff moisture onto a pair of glasses before wiping them with a cloth and mimic phone conversations by chattering wordlessly into a telephone cradled between her ear and the crook of an elbow.

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

Koko can also cough on command—not particularly groundbreaking human behavior, but impressive for a gorilla because it requires her to close off her larynx.

"The motivation for the behaviors varies," Perlman says. "She often looks like she plays her wind instruments for her own amusement, but she tends to do the cough at the request of Penny and Ron."

These behaviors are all learned, Perlman figures, and the result of living with humans since Koko was just six months old.

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

This suggests that some of the evolutionary groundwork for the human ability to speak was in place at least by the time of our last common ancestor with gorillas, estimated to be around 10 million years ago.

"Koko bridges a gap," Perlman says. "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."

Orangutans have also demonstrated some impressive vocal and breathing-related behavior, according to Perlman, indicating the whole great ape family may share the abilities Koko has learned to tap.


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Journal information: Animal Cognition

Citation: Apes may be closer to speaking than many scientists think (2015, August 14) retrieved 15 July 2019 from https://phys.org/news/2015-08-apes-closer-scientists.html
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Aug 14, 2015
"nine different, voluntary behaviors that required control over her vocalization and breathing" is not even the foothills of the foothills of the mountain of human vocal capacities. Humans do not mere speak but can sing, imitate the calls of other animals (as done by many hunters). Even normal speech can be done in a myriad of different ways from whisper, singsong to Donald duck speech (also called buccal speech), an alaryngeal form of vocalization which uses the inner cheek to produce sound rather than the larynx. Humans are just extraordinarily vocally gifted--even birds must envy our ability to sing multiple notes upon single out breaths--they can only sing (with the exception of 30Hz+ trills) one per out breath.

Aug 14, 2015
Are you proposing that human exceptionality is somehow detracting from showing how some of us apes climbed the peak of language? And timing the evolution of that particular trait. Rather it is why we are interested in the evolutionary path. Other human exceptions are:

- We are among the fattest animals around, certainly 2-3 orders of magnitude more adipose tissue (~ 0.1 % in chimps, ~ 10 - 30 % in humans). That is because we were doing exceptionally bad as a species compared to the other extant apes.

- We are good long distance runners and fairly versatile climbers, swimmers, divers. Again because we were bad apes, and had to scrounge and hunt long distances.

- We are among the long lived, and our hearths beat more times than most species. That is likely because we use sex socially, pushing it to older ages, likely because - again - we couldn't swing the wild life but tamed ourselves in order to survive.

Et cetera. Seems most exceptions are due to our failures.

Aug 15, 2015
Animals can not be compared in mental and communicative abilities with humans. They have designed with different puprose. Only the humans are created in the image and likeness of God and is naturaly to have the abilities to comunicate efectively, have imagination and abstract thinking. Тhis enables us to be creators as our Creator, but first we must learn to love.

Aug 15, 2015
Animals can not be compared in mental and communicative abilities with humans. They have designed with different puprose. Only the humans are created in the image and likeness of God and is naturaly to have the abilities to comunicate efectively, have imagination and abstract thinking. Тhis enables us to be creators as our Creator, but first we must learn to love.
I like it when godders speak in absolutes. I like it even better when science proves them wrong.

In coming years chimps will be made to talk. Life wil be found on other planets. The human lifespan will be extended indefinitely. And machines with intellects beyond those of humans will be constructed.

And godders will pretend that their book predicted these things all along.

And the world will laugh at them as usual.

Aug 15, 2015
Yep, saw that movie.

Aug 16, 2015
Somehow this article has threatened a major structural member in a delusion that is shared by many, many psychotics - religious belief. Since it has been learned that the capacity for self delusion has some survival benefit for humans (or at least did at some point) I have lost the naive hope I once had that humans could one day evolve into a rational intelligent life form.

Aug 16, 2015
Humans are just extraordinarily vocally gifted--even birds must envy our ability to sing multiple notes upon single out breaths--they can only sing (with the exception of 30Hz+ trills) one per out breath.

I suggest you learn some avian biology because birds' syrinx is very much more efficient than the human larynx (about 90% air-efficient vs about 2% air-efficient in noise production per exhalation). In addition, because the syrinx is located at the base of the bronchi, there are numerous songbirds that can produce 2 notes at once (a note per lung), a feat quite impossible for a human larynx, and numerous notes per exhalation, and some can further produce much higher, and sometimes lower, pitch than we can hear or vocalise.

This doesn't apply to all birds - some can produce only fairly simple grunting-like sounds - and depends critically on the complexity of the musculature of the syrinx with more complex and numerous muscular control enabling more complex sound production.

Aug 17, 2015
Viko,
You should actually watch some movies on koko

Aug 22, 2015
Incredible. Koko truly does communicate as young human children do by mimicking the human caretaker and now Bonobos who would unlike other higher primates almost always share instead of fight in controlled tests for resources. We and I believe this wholeheartedly have much to learn about and from our closest primate relative "friends"

Aug 22, 2015
Comments made without knowledge seem to be the norm in todays faceless identity less society. Gained true and vetted knowledge that our WWW. can provide in seconds is probably so far the 21st centuries greatest gift to mankind. Cherish it be nice to your fellow "students" in life and above all never stop filling ourselves full of said knowledge. It is very powerful.

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