In 1978, an amazing image of a gorilla taking a photo of itself in a mirror graced the front page of National Geographic Magazine. It was the world’s first look at the incredible creature known as Koko, a lowland gorilla who had been taught to communicate with humans. But she wasn’t just asking for bananas! What she had to say astounded scientists around the world. Let’s find out about how one ape helped us make some of the most important discoveries about animal behavior in human history!
Born in San Francisco Zoo on July 4th, 1971, Koko’s full name was Hanabiko, which is Japanese for fireworks child, how patriotic and poetic! She lived with her mother in the zoo’s gorilla troop until she was six months old, but she was diagnosed with an illness and had to be raised by a human family in the zoo’s nursery. As she began to recover, the young gorilla caught the eye of then psychology student Francine “Penny” Patterson. Penny believed that Koko could be the perfect primate for a revolutionary new study. She proposed that this young gorilla could be taught to speak to humans using sign language! Six months later in July 1972, Koko was moved to Stanford University and Project Koko took off!
Washoe Chimpanzee & Sign Language
The study was based on the findings of a female chimpanzee called Washoe, who the first animal to acquire any kind of human language. Washoe had been raised by humans since infancy, and as part of a study in 1969 she was taught American Sign Language, or ASL. But what was even more staggering was that she used these signs to communicate emotion! Until this point, that was something many had believed to be a uniquely human trait.
In one incredible account from 1982, a volunteer called Kat Beach who worked with Washoe became pregnant. Washoe would often ask about Kat’s pregnancy by signing “BABY” and displayed fascination with her growing belly. Sadly, Kat miscarried. When she returned to see Washoe several weeks later, she told the chimpanzee the news by signing “MY BABY DIED”. But when Washoe responded, it left everyone amazed. She touched her cheek and drew a line down her face, the ASL sign for “CRY”. Chimpanzees don’t shed tears, but Washoe had somehow managed to associate human crying with sadness, a surprisingly human, and empathetic response!
It turned out Washoe had also lost two babies after giving birth and showed signs of depression afterwards. Perhaps she understood what Kat was going through? Then, before Kat left, she signed “PLEASE PERSON HUG”. It seemed like she didn’t want Kat to leave without some emotional support!
Project Koko
Because gorillas are so large and difficult to train, these primates had never been considered for a study like this before. So, teaching 1-year old Koko required a lot of help. In the first 11 months of the project, Koko was in the presence of one or more fluent ASL signers for 10 to 20 hours a week.
They taught her the signs through two methods. The first was called molding, where Koko’s companions would shape her hands into the right configurations and motions. The second was called imitation, where Koko was encouraged to form the same sign after it had been used by a teacher. In the clip below, Penny uses the sign for “CANDY” first, and then moves Koko’s hands to imitate the gesture, before rewarding her with the sweet treat. Looks much tastier than a banana!
Penny and Koko: Reflections on Motherhood (2018) by kokoflix
But how could the researchers know that Koko was really communicating, and not just mimicking behaviors that she’d associated with tasty treats? In Project Koko, a sign like this would only be considered reliably learned if it met some scientific criteria. One of those criteria was that it had to be witnessed and recorded by two independent observers. This stopped people lying or being mistaken about what they saw. Another was that Koko had to spontaneously use a sign on at least half of the days of any given month. This meant that it was being both remembered and learned. And finally, it had to be used appropriately, so that she learned specific signs related to specific things! So, with all the science in place, how quickly would Koko pick up on this new, alien language? Amazingly, it took just a few weeks of training before she signed her first word on her own! It was a close approximation of “FOOD” or “EAT”! Next came “MORE” which you can see she does by pushing her fingertips together, and soon after she learned “DRINK” as you see here in the clip below.
Koko learns to sign Eat, Food, and More as a baby gorilla by kokoflix After the first 2 years, her teaching increased to 8 and a half hours a day, that’s longer than most schools days! By the time she was 3 ½, Koko’s vocabulary had expanded to include 100 signs which met the most stringent criteria, along with almost 300 more that she used spontaneously!
By that age, most human children have a vocabulary of about 1000 words. Even though that seems like a big gap, Koko wasn’t that far behind. In fact, she could use the same number of words that an average 2-year-old would know. For a gorilla, that level of progress was astonishing! By the age of 5, she was regularly using 500 to 600 signs, and could string signs together in a sentence to communicate her wants and needs. According to the speed of her development, this gave her an IQ of about 85! For some perspective, human average is around 100, which means Koko must have already been smarter than most people in Florida!Between 1972 and 1982, the amount of new words Koko learned each year was anything between 2 and 200, but she never stopped trying! Here, in 2009, you can see how she learned to sign “BUTTERFLY” for the very first time. Sometimes she was quite literally winging it!
Koko learns a new sign: Butterfly by kokoflix However, Koko wasn’t a completely blank slate when she first started learning how to sign. Penny later discovered that gorillas and other apes have a natural, gestural language. While it’s a lot less complex than American Sign Language, apes use these gestures to communicate with each other, which could help to explain how Koko was able to pick up human sign language so quickly.
But she still had to adapt certain ASL signs to fit her gorilla-sized hands! Gorillas have much smaller thumbs in proportion to the rest of their bodies, making it harder for her to make signs like the letter K, for example. Having two K’s in her name, you can imagine how this presented something of a challenge! Instead, she adapted the sign for her name to a simple shoulder pat. By making these changes, she created a new language variant called "Gorilla Sign Language".
Koko & Michael
Then in 1976, Koko’s world got even bigger. Penny introduced another young gorilla called Michael into her human family. Initially, the two didn’t get on at all! Koko wasn’t ready to stop being an only child, and they often ended up going from playful fights to hardcore wrestling matches! Eventually, they began to enjoy each other’s company, and started to play games that Koko called "Quiet Chase", though you probably know it better as hide and seek!
Once he was all settled in, Michael was then also taught sign language, with Koko close by for help. In just 12 months, he had learned to use over 20 signs! As the gorillas interacted, they were able to practice signing with one another, and Michael even taught Koko the names of 2 different researchers called Ingrid and Karen.
Meet Michael by kokoflix Despite the obvious strides they had made in their development, both the gorillas grasp on the human language was far from perfect. Even when, at their peaks, Koko knew over 1,100 signs and Michael knew about 600, there were quite a lot of gaps still left in their vocabulary. This meant that Koko could sometimes over generalize the meaning of a sign. For example, she would use the sign for “STRAW” to refer to anything that looked like a plastic drinking straw, like tubing, a pen, cigarettes, or even a car antenna.
Clever Hans & The Burden Of Proof
With these minor faults in mind, how did the researchers prove that the gorillas were actually learning the signs, and not just guessing the right answer? This tricky conundrum is known as burden of proof, and it’s something that has been a problem in animal psychology since the famous incident of Clever Hans.
Let’s stop monkeying around for a moment, and travel back to the beginning of the 20th century and into the stable of a horse called Clever Hans. Hans wasn’t called ‘clever’ for no reason, this horse could apparently do math! His trainer, Wilhelm Van Osten, had taught the horse to tap its hoof against the ground to answer math questions.
So, if he said, “What’s 6 plus 15?” Hans would tap his hoof 21 times before being rewarded with a tasty treat! He was right almost all of the time and could even answer questions from other people as well! But scientists weren’t convinced. After some rigorous tests they discovered that if Clever Hans could not see his examiner, then he could not answer the question. The truth is Hans didn’t know math, but he had been able to associate certain cues from the examiner with a tasty treat at the end. These small cues, like looking down at the horses hoof to start tapping and looking back up to stop, were just the same as teaching a dog to do tricks.
Talking Gorillas: Gorilla Sign Language
After that short detour, let’s get back to the gorillas! How could the researchers prove that Koko and Michael really were learning sign language, and not just associating hand gestures with snacks? To prove that she was smarter than the average ape, Koko was put through a series of tests when she was 4 years old.
These involved one researcher placing an object in a box with a clear glass panel so that Koko could see the item, but that a second researcher could not. Then, Koko was asked “what is in the box?”. At no point did the second researcher see what item was put in the box. This kind of test is called a
double-blind, which means that the results can’t be affected by human interference! The items were all things Koko was familiar with and could sign for, like a slide viewer, or a flower. Of the 50 items she was shown, she got 31 correct. She sometimes made errors based on the kind of item being shown, like mistaking a piece of candy for a cracker. Sometimes she used a sign that was similar in form to the answer, but not quite right. Other times, she would ignore the question completely and ask for the box to be opened by signing “KEY, OPEN” or “KEY, BOX”! Even though it was far from a perfect score, getting 62% right was still a high result! Most importantly, it proved that Koko wasn’t looking for cues from her researchers or companions, unlike not-so-Clever Hans!
But objects and names only made up part of Koko and Michael’s vocabulary. Being surrounded by people every day, emotions were a huge part of their daily interactions. They were taught signs for different feelings, such as “CRY”, “LOVE”, and “SAD” which look almost identical to the human ASL variants. It helped them express themselves and tell stories. But they weren’t always nice. Michael, who at this point was a 450 lb alpha male, recounted a terrifying incident from his infancy when he was asked the question ‘What happened to your mother?’ Take a look at the words he uses:
Gorilla Michael's (Bushmeat) Story by kokoflix It doesn’t take a scientist to work out something very bad happened here. Michael was born in Africa, at a time where deforestation and hunting pushed the existence of the countries gorillas to its brink. From his disturbing account, researchers believe Michael witnessed his mother being killed by poachers for bushmeat. The horrendous event left him orphaned and in captivity. The gorillas also had no trouble using their newly-learned language to express their thoughts and opinions about new people they met, and they weren’t always so nice! When Koko was interviewed by Cynthia Gorney, a writer for National Geographic, back in 1985, she didn’t seem to warm to her at first. In fact, as Gorney recalls, Koko called her a toilet via sign language. So, it seems like she had a great sense of humor, too!
Koko And Kittens
But these “talking” gorillas weren’t all doom, gloom and attitude, there are plenty of quirky anecdotes about them too. It may sound strange, but Koko even developed a total fascination with cats!
In 1983 she requested a cat of her own for Christmas. Researchers bought her a stuffed cat, but when it was given to her, she repeatedly signed the word for “SAD”. So, on her birthday that year, she was given her own real kitten! She named the tailless kitty "All Ball" because when he curled up, he looked like a tiny ball. She treated him gently, and the two of them spent hours playing together.
Koko the Gorilla plays with her kitten, All Ball by kokoflix The pairing was so unusual that a photo of Koko cradling her feline friend made another National Geographic cover, changing the way people saw these intimidating primates around the world! The sweet saga was even turned into its own 16 ½ minute film, as well as a book.
But All Ball would teach Koko an important life lesson. One evening, the little cat was hit by a car, and Penny had to break the terrible news to Koko. She’s a braver person than I ever will be! Koko movingly responded with the signs for “BAD”, “SAD”, “FROWN”, and “CRY” repeatedly, clearly mourning the loss of her beloved little kitten.
Both Koko and Michael showed the world that gorillas were capable of complex emotions like loss and grief. The only real difference that seems to separate them from humans is that they can’t articulate their feelings through words!But Koko’s love of cats didn’t die with All Ball! She soon found new friends in several other kittens and was just as gentle and nurturing with them! Even later in life, her fascination with the little furballs tugged on heartstrings all over the world. Did you ever think you’d see a gorilla asking to have a kitten put on its head? If that doesn’t make you crack a smile, you must really have a heart of stone!
Meet Koko's New Kittens by kokoflix Koko & Robin Williams
The story of this precious primate earned her some serious media attention, and celebrities from far and wide soon wanted to spend time with her. In 2001 comedian Robin Williams was invited to meet her. The actor had been used to captivating crowds of thousands of people with his timeless humor, but here his audience of one did all the performing.
At one point Koko even took his glasses and did her best impression of the famous funny man! They played together, and she even managed to make him laugh by trying to delve into his pockets. But what was most amazing is that she seemed to recognize him. When given a VHS box of one of his movies, she quickly pointed him out on the cover!
Koko's Tribute to Robin Williams by kokoflix Sadly, Koko had to experience the hardships of grief once again when she was told in 2014 that Robin Williams had passed away. At first,
she was somberly quiet. But when she saw an upset woman who had worked with Robin during his visit, she made the signs for “WOMAN” and “CRY”. After that, Koko became very still, with her head bowed and her lip trembling. It was yet another example of how Koko could relate to something beyond herself, giving even more insight into how animals could connect with people in a way we had never known before.
Koko's Toys
Despite her deep connection to people, it’s important to remember that Koko was still, fundamentally, a gorilla. As she approached the age of 10, she began showing interest in having a baby. Not a human baby, but a gorilla infant! She once pointed at an image of a gorilla mother and infant, signing “ME, THAT”. It seemed like her biological clock had started ticking!
Following one miscarriage, Koko would sadly never become a mother. But that never changed her maternal instincts! The way she treated her dolls, specifically her gorilla dolls, showed her nurturing side. She would move their hands like she was teaching them to sign, as if she were trying to pass on everything she had learned!But, as we learned with the toilet incident, Koko didn’t always act so innocent! At the age of three, Koko used her powers of communication to craft her first ever lie. She had broken a toy cat in her den, but when she was asked about it, she replied “KATE, CAT” apparently blaming one of her researchers, Kate. However, Koko might have meant that Kate was with her when the cat was broken. In which case, no harm done.
But another event definitely caught Koko red handed! She’d sat on the facilities kitchen counter, but the counter couldn’t take the weight of a 5-year-old, almost 300 lb, gorilla and the top caved in! When Penny questioned her about it, Koko replied “KATE, THERE, BAD.” Either Kate weighed the same amount as a young gorilla, or Koko really had it out for her! What a mischievous monkey.But as you might expect, Koko wasn’t the only one who was caught trying to dodge blame. Michael once ripped the jacket of a visiting volunteer called Ellie. When she asked, “Who ripped my jacket?” Michael made the sign for “KOKO”! Seems like it’s every gorilla for themselves. When asked again, he had the audacity to place the blame on Penny! Finally, he confessed, by signing “MIKE”.
Conversations With Gorillas
But Koko and Michael’s relationship with the English language also went beyond sign language! Researchers spoke to the two young gorillas as they were signing and learning, so that they could associate meaning to the words as well as the signs!
At the time, it was considered almost impossible that animals could understand spoken human language. The idea even went against one of the main theories of language development, called the
Motor Theory of Speech Perception. This theory explained that a crucial component of understanding words is knowing how to say them. For example, what’s the word “ANTIDISESTABLISHMENTARIANISM?“
Did you just try to sound it out, or break it down by syllables? That’s your motor system in action! It’s why we sometimes repeat words we haven’t heard before, or why children learning to speak repeat phrases they’ve heard but don’t understand. Without being able to articulate the word, it was proposed that speech could not be understood. But then along came Koko, and you can see how she follows Penny’s verbal instructions.
A Conversation With Koko The Gorilla: Full Documentary by ahamo The older Koko got, the more complex questions she could follow. Here, she’s being asked about how she’d like to expand her family. Without using any sign language, Penny presents four options to Koko, and asks which one Koko would like the most.
Koko Chooses How She'd Like to Expand her Family by kokoflix Not only did Koko understand, but she also chose the option that was closest to resembling a gorilla troop. In other words, it was the option that made the most sense! So, it wasn’t just a guess, Koko could understand English to an extent. Utterly mind-blowing!
Not only that, but Koko also used the sounds of some words to come up with her own signs! Because she couldn’t speak aloud to ask what something was without knowing the right signs, she’d have to get creative. One day, Koko was craving some browse. It’s a kind of leafy green vegetable mix that she was given between her meals. While she’d had it almost every day and heard its name many times, it had never been given a specific sign. So how do you ask for something when you don’t know its sign, and can’t talk? Showing just how clever she was, she began pointing to her eyebrows. At first it confused her keepers, but then they realized she was holding her hand to her eyebrows. Koko knew that “Brows” and “Browse” sounded similar, and by making the connection she was able to communicate just that! She also made up sign combinations to try and expand her knowledge of the world, so combos like “EYE” and “HAT” meant mask, and “FINGER” and “BRACELET” meant ring! But that wasn’t all, Koko and Michael had even more creative talents hidden up their huge furry sleeves! Both of them liked to paint, which let them express themselves in yet another human manner. Michael painted this pictured and called it “Apple Chase.”
To you and me, this looks like a 2-year-old just went to town on the canvas. But the colors and the name are very important. Apple was the name of Michael’s favorite dog, a black and white pooch who would play games of chase with Michael around his enclosure. Of all the paint colors he was given, he chose those black and white colors, along with the name Apple Chase! Koko did the same, purposefully choosing specific colors from a palette and creating artistic impressions of things she felt and saw, like “LOVE”.
You might have expected her to use yellow to indicate her love of bananas, but similar to humans, she chose colors like pink and orange to represent the warm feeling!
The Voice Of Nature
In 2015, Koko’s unique voice was used to communicate with the whole world about an important topic threatening us all. NOE Conservation, a French charity protecting biodiversity, teamed up with Koko’s carers at the Gorilla Foundation. They informed Koko about what was at stake at the upcoming United Nations Climate Change conference and asked for her thoughts. Take a look at what she said:
Koko the gorilla is the voice of Nature at COP21 by Noé She goes on to sign that we need to hurry and fix the earth, and that nature needs us to help, finishing with a very polite “THANK YOU,” demonstrating more manners than most humans! Greta Thunberg would be proud. While it’s clear that her response had been heavily edited and perhaps her response was not entirely spontaneous, the signs themselves were undisputable. “FIX EARTH” and “MAN STUPID” have pretty clear meanings if you ask me! However, we don’t know if Koko really understood what climate change was, and sadly, we never will.
Koko passed away in her sleep in 2018 at the age of 46. Her best friend Michael also made his way up to that heavenly jungle in the sky 18 years before. Both of these amazing apes established that interspecies communication is possible, but Koko had also left humanity with a huge lesson. She had emotional depth. She could love, learn, and grieve similarly to humans. Of course, there are still doubters. Some have pointed out that apes communicate mostly through functional signs, like asking for food or toys. Others claim that Koko’s signs were elicited by her handlers asking her questions. Whatever you think, one thing is clear: Koko’s taught us valuable lessons about understanding animal and human communication. You could say she made one small step for apes, and one giant leap for ape-kind!
