Dogs understand what certain words stand for, according to researchers who monitored the brain activity of willing dogs while they were shown balls, slippers, leashes and other highlights of the domestic dog world.
The finding suggests that the canine brain can reach beyond commands like “sit” and “fetch”, and the insanity-inducing “walkies”, to grasp the essence of nouns, or at least those that refer to items for which the animals care
“I think the capacity is there in all dogs,” says Marianna Boros, who helped organize the experiments at Eötvös Loránd University in Hungary. “It changes our understanding of language evolution and our sense of what is uniquely human.”
Scientists have long been fascinated by whether dogs can actually learn the meaning of words and have accumulated evidence to support the conjecture. A survey in 2022 found that dog owners believed their furry companions responded to between 15 and 215 words.
More direct evidence for cognitive skills in dogs came in 2011 when psychologists in South Carolina reported that after three years of intensive training, a border collie named Chaser learned the names of more than 1,000 objectsincluding 800 cloth toys, 116 balls and 26 Frisbees.
However, studies have said little about what happens in the dog brain when it processes words. To delve into the mystery, Boros and her colleagues invited 18 dog owners to bring their pets to the lab along with five objects that the animals knew well. These included balls, slippers, frisbees, rubber toys, cues and other items.
In the laboratory, the owners were instructed to say words to objects before showing their dog either the correct item or another one. 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 through non-invasive electroencephalography, or EEG. The tracks revealed different patterns of activity when the objects matched or clashed with the words their owner said. The difference in the traces was more pronounced for words that owners believed their dogs knew best.
Similar blips in EEG recordings were seen when people performed the tests and were interpreted as people understanding a word well enough to form a mental representation that was either confirmed or confused by the object they were later shown.
Writing in Current Biologythe scientists say the results “provide the first neural evidence for object word knowledge in a non-human animal”.
Boros emphasized her claim that dogs do not understand words as well as humans. It will take further work to understand, for example, whether dogs can generalize in the way humans learn as infants, understanding that the word “ball” need not refer to one specific, heavily chewed spongy sphere.
The study raises the question of why, if dogs understand certain nouns, more of them don’t show it. One possibility is that a dog knows what a word refers to but hasn’t bothered to respond to 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 could be widespread through mammals,” she said. “This in itself is highly exciting as it sheds new light on language evolution.
“It could be that the dogs don’t really care enough about the game of ‘fetch this particular thing’ to play along with the way we’ve trained and tested them so far. Your dog may understand what you are saying but choose not to act.”
