Dogs have an innate ability to recognize nouns, forming mental representations of the objects they hear referenced with words. And while our furry friends may have kept this remarkable power hidden up to now by generally refusing to fetch items on demand, a new study on canine brain activity has given them away.
Until now, most research into dogs’ linguistic skills had tested their ability to retrieve specific objects, with disappointing performances making it difficult to assess the extent to which pooches recognize reference words. To gain a deeper understanding, the authors of the new study used non-invasive electroencephalography (EEG) to measure the animals’ brain activity when hearing nouns from their learned vocabulary.
The researchers had 18 dog owners call out the words for toys that their pets knew by name, before holding up either said item or a mismatched object. Observing the dogs’ EEG readings, the study authors noted that this brain activity differed depending on whether the displayed toy matched the recited word or not.
For instance, when the dogs were presented with a mismatch, their brains reacted by producing a signal resembling what’s known as the “N400 effect” in humans. This particular brain response generally arises when we hear or read words that don’t line up with our expectations and is seen as “a well-established neural correlate of semantic processing,” the authors write.
In a statement, study author Marianna Boros explained that the presence of this signal in the dogs’ ECG readings indicates that “they activate a memory of an object when they hear its name.”
“Your dog understands more than he or she shows signs of,” added co-author Lilla Magyari. “Dogs are not merely learning a specific behavior to certain words, but they might actually understand the meaning of some individual words as humans do.”
The strength of this effect was generally stronger for words that dogs were more familiar with, thus supporting the conclusion that the animals really do understand nouns. Furthermore, the researchers found that this ability is not dependent on the size of a dog’s vocabulary, indicating that semantic processing is inherent to the species and doesn’t arise as a product of extensive training.
“It doesn’t matter how many object words a dog understands – known words activate mental representations anyway, suggesting that this ability is generally present in dogs and not just in some exceptional individuals who know the names of many objects,” said Boros.
Despite the advanced linguistic skills illustrated by the dogs’ brain activity patterns, the study authors explain that the animals probably don’t process words in the same way as human adults, or even babies. For instance, they write that “when learning the meaning of a word, infants grasp that words refer to categories, not individual objects.” In contrast, the dogs involved in this research displayed “one-to-one mapping of object names to individual objects, but not mapping to categories.”
Nonetheless, they say that the ability to understand words for specific items “assumes that dogs have to evoke the mental representation of the object upon hearing its name and thus link the two in a referential manner.”
The study is published in the journal Current Biology.
