Dogs have long shown that they can respond to such instruction words as sit, fetch, and come. They have more difficulty differentiating between objects — say a Frisbee or a ball. Earlier research shows that, when asked to choose between two items, dogs pick the correct one about half the time — no better than a coin flip. But a new study shows dogs’ brains respond about as well as a human’s when presented with familiar versus unfamiliar words, according to a study in Current Biology.
Marianna Boros of the Department of Ethology at the Eötvös Loránd University, Budapest, and colleagues wanted to understand this discrepancy. Some of the confusion may be due to the nature of the earlier experiments, as well as a dog’s training, background, and personality. “My dog, he has a few toys, but he only cares about one single ball,” says Boros. “It’s possible that they know the word but don’t understand the task.”
Patterns of Understanding
So, the researchers decided to look directly at brain activity rather than just rely on how dogs respond to a command. Many studies have been done on humans — including infants, nonverbal people, and adults — that show different brain electrical information depending on whether these subjects hear words they know or objects that match a word. Those tests are widely accepted as evidence that the subject understands the words.
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After familiarizing both dogs and their owners with the laboratory, researchers used adhesive cream to attach EEG monitors to the dogs’ heads. The dog and owner then made themselves comfortable on either a couch or a mat. Then, the owners showed the dogs a series of objects — some that matched the owners’ words and some that didn’t.
The results revealed different patterns of electrical activity in the brain when the dogs saw things that matched a spoken word versus a word that didn’t represent the item shown. The dogs performed about as well as humans in similar tests, with 14 of 18 exhibiting brain activity indicating understanding.
Our Dogs, Our Selves
Comparing how dogs and people process words can help explain how humans learn language. “By understanding animals better, we also understand ourselves better,” says Boros. The way we use and learn language may change over time. The same goes for dogs. For instance, dogs might have needed to learn action words because,
not long ago, more worked as herders or retrievers. As more become pets rather than workers, dogs may gain more understanding of words that stand for objects.
The researchers wonder about how other mammals might perform in similar tests. Boros also says similar experiments could be performed using fMRI — but it’s much harder to train dogs for such studies. It can take up to six months to prepare them for such work.
Boros says these kinds of studies can show what humans have in common with animals and what sets us apart. “It’s not trivial about what is shared among all mammals and what it uniquely human,” she says. “We put ourselves on a pedestal, and then it turns out that we are not so unique after all.”
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