If you talk to dog owners, they’ll often swear by their pet’s ability to understand their words, but it’s only recently that scientific evidence has backed up such claims. According to researchers who imaged the brains of dogs while the canines processed words of objects, dogs may have at least a rudimentary neural representation of meaning for words that they have been taught.
Eddie, one of the dogs whose brain activity was scanned with a fMRI scanned. Next to the dog are the toys used in the experiment, “Monkey” and “Piggy”. Credit: Gregory Berns.
“We know that dogs have the capacity to process at least some aspects of human language since they can learn to follow verbal commands,” said Emory neuroscientist Gregory Berns, senior author of the study. “Previous research, however, suggests dogs may rely on many other cues to follow a verbal command, such as gaze, gestures and even emotional expressions from their owners.”
Berns is one of the founders of the Dog Project, which is looking to probe the evolutionary history of man’s best friend. The project was the first to train dogs to voluntarily enter and sit still in a functional magnetic resonance imaging (fMRI) scanner, which to dogs, looks like a loud and intimidating machine — but they braved through it.
Working at the Dog Project, researchers had previously gained insights about the neural inner workings of canines, such as how dogs process faces and odors. Previously, researchers at the MTA-ELTE Comparative Ethology Research Group in Budapest used fMRI to show that dogs have an uncanny ability to pick up our emotions only from our speech, suggesting that our canine friends are able to sense our emotional currents through changes in the tone of our voice. This time, the researchers were looking to investigate how dogs process words.
To this aim, 12 dogs were trained by their respective owners to retrieve two different objects when these were called out by name. The objects had to look and feel different in order to facilitate discrimination, such as a stuffed animal or a rubber toy. Training was considered complete when a dog consistently retrieved the requested toy when presented with both of the objects.
In one experiment, the dog had to stay in a fMRI scanner while the owner, who stood in front of the machine’s opening, called out the names of toys, then showed the corresponding objects. For instance, when Eddie, a golden retriever-Labrador mix, heard the words “Piggy” or “Monkey”, the owner would hold out the matching toy. Sometimes, the owner would utter gibberish words such as “bobbu” and “bodmick” and held up novel objects that the dog had never encountered before.
The fMRI scans revealed that the dog’s auditory regions in the brain became more activated when they heard the words for novel objects, compared to trained words. This result was rather unexpected because it’s the exact opposite of how people’s brains behave — we typically show greater neural activity for known words than for novel words.
While we can’t ask dogs what’s up, the researchers hypothesize that the dogs may show greater neural activation in the auditory region of the brain because they’re paying more attention to novel words — perhaps sensing that their owners want them to obey a command. Dogs know that they will receive a treat if they please their owners, so there may be an incentive to be more attentive to novel words.
Half of the dogs showed increased activation in their parietotemporal cortex, a region of the brain that the researchers say may be analogous to the angular gyrus in humans, which is where the meaning of words are processed. The other half of the canines showed heightened activity when they heard novel words in other brain regions, such as the left temporal cortex and amygdala, caudate nucleus, and the thalamus.
These differences may be due to the fact that the different breeds and sizes of dogs.
But the big takeaway of this study, published in the journal Frontiers in Neuroscience, is that dogs appear to have a neural representation for the meaning of words they’ve have been thought — a response which seems beyond a conditioned Pavlovian response. In other words, it seems like your dog might understand some of what you’re saying after all.
