Dogs understand what certain words mean, according to researchers who monitored the brain activity of volunteer dogs while they were shown balls, slippers, leashes and other highlights of the domestic canine world.
The findings suggest that the dog’s brain can move beyond commands such as “sit” and “fetch” and the frenzy-inducing “walks” to grasp the essence of nouns, or at least those that refer to objects that interest animals.
“I think all dogs have this ability,” said Marianna Boros, who helped organize the experiments at Eötvös Loránd University in Hungary. “It changes our understanding of the evolution of language and our sense of what is specifically human.”
Scientists have long wondered whether dogs can actually learn the meanings of words and have gathered evidence to support their suspicions. A survey in 2022 found that dog owners thought their furry companions responded to between 15 and 215 words.
More direct evidence of canine cognitive prowess emerged in 2011 when psychologists in South Carolina reported that after three years of intensive training, a border collie named Chaser had learned the names of over 1,000 objectsincluding 800 fabric toys, 116 balls and 26 frisbees.
However, studies have learned little about what happens in the canine brain when it processes words. To unravel the mystery, Boros and his colleagues invited 18 dog owners to bring their pets to the lab along with five objects the animals were familiar with. These included balls, slippers, frisbees, rubber toys, leashes and other items.
In the laboratory, owners had to say words to designate objects before showing their dog either the correct object or another. For example, an owner might say, “Look, here’s the ball,” but instead hold up a Frisbee. The experiments were repeated several times with matching and non-matching objects.
During the tests, researchers monitored the dogs’ brain activity using noninvasive electroencephalography, or EEG. The traces revealed different patterns of activity when the objects matched or clashed with the words spoken by their owner. The difference in traces was most pronounced for words that owners thought their dogs knew best.
Similar signals in the EEG recordings were observed when humans performed the tests and were interpreted as people understanding a word well enough to form a mental representation that was either confirmed or confounded by the object they were then shown.
Writing in current biologythe scientists say the results “provide the first neural evidence of object word knowledge in a non-human animal.”
Boros emphasized that she is not claiming that dogs understand words as well as humans. It will take further work to understand, for example, whether dogs can generalize in the same way that humans learn to do as infants, and to understand that the word “ball” need not refer to a sphere specific spongy and heavily chewed.
The study raises the question of why, while dogs understand some names, more of them do not. One possibility is that a dog knows what a word refers to but doesn’t care to act on it. “My dog only cares about his ball,” Boros said. “If I bring him another toy, he doesn’t care at all.”
Dr Holly Root-Gutteridge, a postdoctoral researcher at the University of Lincoln who was not involved in the study, called the work “fascinating”.
“It’s particularly interesting because I think it’s unlikely that it started during domestication, so it might be widespread among mammals,” she said. “This is very exciting in itself because it sheds new light on the evolution of language.
“The dogs may not really care for the ‘fetch this particular thing’ game to follow the way we have trained and tested them so far. Your dog may understand what you say but choose not to act.