Move over to Dr. Doolittle. After spending a year indoors with our pets, we might think we can talk with animals better than ever. We interpret some barking as excitement, some meowing as anger.
But what if our pets actually try to talk to us?
Scroll through social media enough and you will meet a famous dog on Instagram named Stella. Why is she famous? Well, Stella’s owner Christina Hunger is a speech therapist and is wondering if she could learn to talk to her dog. Using a few buttons with words recorded in their voice (like the “It was easy” button that everyone apparently bought from Staples in the 1990s), Hunger taught Stella to press it to communicate her thoughts. wants and needs. When she is hungry she can press “eat” and when she wants to go for a walk, she can press “outside”.
Over the years, the collection of a few buttons has grown into a huge network of 48. In one of her most recent videos, Stella hits “No.” Out. Come. Out. ”To which Hunger replies,“ You’re right, we’re not out yet. ”
Watch enough of these videos and you might be mesmerized by Stella’s linguistic ability, but Stella and her buttons have sparked a debate over whether what she does really matters as language. In the scientific community, the debate over whether and to what extent non-human animals can acquire language has been around for decades.
Language learning poster kids
The mid-20th century sparked interest not only in conspecific communication (between members of the same species), but also in interspecies communication (between members of different species). Specifically, communication between humans and other animals. In the late 1940s and early 1950s, researchers Keith and Catherine Hayes attempted to teach a chimpanzee named Viki how to speak. After years of training, Viki was only able to produce four words: “mum”, “dad”, “cup” and “top”.
Because of the difficulty chimpanzees have in producing speech sounds, other studies have turned to communication with hand gestures. Two of the most famous creatures to have learned the signs are Nim Chimpsky and Koko the gorilla. Having learned over 1,000 American Sign Language-derived gestures, Koko was revered by many as “having learned ASL.” But this interpretation has been widely discredited by language experts due to the limited scope, complexity, and sequence length of Koko’s signs.
In the realm of non-primates, a famous parrot named Alex has been studied by animal psychologist Dr Irene Pepperberg for over 30 years. By the end of his life, Alex knew over 100 different voice tags for objects, actions, and colors. He could look at a group of objects and tell Pepperberg how many green objects or cubes or keys were in front of him.
A final example of an awesome word learner is a border collie named Chaser. Over a three-year period, Chaser was able to learn over 1,000 proper names of objects. Its owner, Dr John Pilley, would introduce Chaser to a new toy by saying “This is __”, then he would hide the toy and ask him to find it. What started with a few toys eventually grew into an impressive collection of 800 cloth animals, 116 balls, 26 frisbees and over 100 plastic toys.
While not all of these examples allow animals to learn a full human language, they remain remarkable examples of animal abilities to communicate with humans. So what about the four legged animals that live in our homes? They communicate with us all the time, right?
Read facial expressions
Let’s start with an obvious center of communication: the face. I often take my dog’s smiles to mean he is happy when I might interpret raised eyebrows as a concern. Are dogs really able to communicate with their faces, or am I just imagining things?
Researchers have shown that domestic horses are capable of producing 17 different facial expressions, domestic cats are capable of producing 15 facial expressions, and dogs can produce more than 20 facial expressions.
We humans are much better at differentiating all the raised eyebrow lines and ears that dogs make than those created by other pets. Additionally, dogs can recognize human facial expressions, which is not as well proven for cats or horses. In fact, humans are better at reading facial expressions made by dogs than we are at reading facial expressions made by our closest living relative, the chimpanzee.
Cat owners may disagree with the idea that humans and cats have no special connection with facial reading. Many of my cat-owner friends say their feline pets show calm contentment by slowly blinking and sometimes fully closing their eyes.
Recent research by Tasmin Humphrey and colleagues at the University of Sussex investigated what animal scientists call the “slow flashing sequence”. In the laboratory, the slow blink sequence is defined as a series of half-blinks followed by either a long narrowing of the eyes or a complete closure of the eyes.
The team observed that after seeing their owners blink slowly, cats were more likely to initiate their own slow blink sequence! The team also compared how the cats reacted to unknown experimenters giving either a slow blink or a neutral face to the participating cats. Cats were much more likely to approach the experimenter after seeing a slow blink. It seems that cats and humans use slow blinking sequences to communicate positive and relaxed emotions to each other. Even when they are strangers!
This awkward rear sniff by a dog is the canine equivalent of a handshake. Dogs use their sense of smell, also known as olfaction, to identify us and our emotions. This is probably due to their remarkably sharp sense of smell. In fact, their odor detection is about 10,000 times better than that of humans. Dogs have been proven to be able to identify their owners and distinguish between their owner’s scent and a stranger’s scent, even without either person in the room.
More surprisingly, dogs use their awesome sense of smell to sense our emotional states. Although body odor seems unpleasant to us humans, it contains important chemical signals that convey information about how we feel. Human smells communicate negative emotional states like fear and disgust, but they have also been shown to communicate positive emotional states like happiness. As humans, we often feel them without even knowing it! When we receive any of these chemical signals, we automatically display a less intense version of the emotional state the other person is in.
It turns out that dogs do something similar! In one experiment, waste pickers sniffed body odors from people who were either fearful or happy at the time their sweat was collected. After a joyful burst of sweat, dogs were more likely to exhibit “happy behaviors,” such as approaching and interacting with a stranger. Meanwhile, sniffing the sweat of anxiety made subjects more likely to exhibit frightening behaviors like retreating to their owner and avoiding the stranger in the room.
Although dogs are naturally good at distinguishing smells, they likely learn associations between our smells and our emotions throughout their lifetimes.
Considering what we know about the famous border collie named Chaser, it’s no surprise that pets can learn human words with training. Teaching our dogs to “sit” and “shake” can take some time, but they get the hang of it. But can humans use vocal sounds to communicate with other species without training them? Surprisingly, yes!
Such a human-animal connection has developed for hundreds of thousands of years. In Mozambique, honey hunters use a distinctive appeal to attract the attention of wild birds, called great honey guides, who instinctively lead them to the nests of wild bees. Once the cross-species team reaches their destination, the human subdues the hive and takes the honey, while the honey guide takes the beeswax.
Claire Spottiswoode, an evolutionary biologist, and two collaborators in South Africa investigated this ancient connection by comparing the specialized sound “brrrr-hm” used by honey hunters with other human and animal sounds. They discovered that honeyguides don’t reveal their hive secrets in response to an old sound. When playing a recording of the specialist call, researchers were much more likely to be led by a honey guide to a honeycomb.
Considering how hard I have to work to teach my dog to turn around, it’s impressive that the honeyguides seem to instinctively respond to a human’s “brrr-hm” call by quickly guiding them to the spot. where they need to go. Even if the dog in your house or the bird on your patio hasn’t learned the names of 1,000 different toys, they still care and communicate with you in their own way. And, even when you are not aware of it, you are also communicating with them.
Nora Bradford is a doctoral candidate in cognitive science at UC Irvine and a writer for NPR’s “Loh Down on Science”.