When a dog hears a familiar word, its mind remembers and draws an image of the object it refers to. This ability is transversal to all dogs, and does not depend on their age, breed, or the number of words they know. This is concluded by a study by the universities of Eötvös Loránd, in Hungary, and Stavanger, in Norway, published this Friday in the journal Current Biology.
Previous experiments on dogs, apes and dolphins had suggested that the ability to relate words to objects was something reserved only for exceptional individuals of these species, and that they could only acquire it after intense training. The current work generalizes the skill, for the first time, to an entire non-human species.
“This can change the way we think about animal communication and the evolution of language,” explains Marianna Boros, a neuroethologist at the Hungarian university and one of the authors of the work, in an email to La Vanguardia. “If dogs as a species are capable of understanding communication about the outside world, we may want to reconsider whether other mammals are capable of doing the same,” she concludes.
The key that has led researchers to be able to generalize the ability for the entire species has been a change in the research approach. Until now, all studies had conducted behavioral experiments. The owners said a word to the animals, and they had to choose the object to which it referred (pointing to it or appropriating it). The results were always negative, except for a few specific individuals.
However, these jobs not only required the animals to understand the words, but they had to demonstrate this knowledge, which required combining skills. The new research has focused exclusively on analyzing comprehension. He has done this by measuring the brain activity of 18 dogs using non-invasive encephalography, that is, placing external electrodes on the animal's skull.
In the experiment, the owner of each dog pronounced a word known to the animal and then showed an object that may or may not match the word. Sometimes, for example, he would say “ball” and show a stuffed animal, or a bone; and other times, he showed the ball. Brain activity when the word and toy coincided was different from when they did not, and the difference was accentuated the more familiar the dog was with the object.
This different signal constitutes a neural marker that has also been observed when testing in humans, and that the field has accepted as evidence of word understanding. Even so, just because dogs are able to understand what object we are referring to when we use a known vocabulary does not mean that they learn like we do, the authors warn in their article.
A characteristic of human beings is that already in their first steps in learning they are able to generalize, that is, to understand that a word does not refer to a single specific object, but to many others with similar characteristics.
In the experiment, "when we tested the word 'ball' we did not show them just any ball, but in each case the one that belonged to the dog," explains Boros. “We don't know if the dog would have shown the same reaction if we had shown it a different ball,” he reasons.
In any case, the discovery changes the way we understand the relationship between dogs and words, which until now was based on their ability to follow instructions. “Dogs not only learn specific behavior in relation to certain words, but they could understand the meaning of some individual words just as we humans do,” says Lilla Magyari, a researcher at the Hungarian and Norwegian centers, and also co-author of the study. .
“Your dog understands more than he shows,” he concludes, given that all of them understand the meaning of some words, but very few are capable of acting or demonstrating it. Understanding the reason behind this statement is one of the next steps that researchers want to solve.
Another pending question is whether the learning of words that refer to objects is something transversal in the animal world, or if it is a specific characteristic of dogs, developed evolutionarily due to their close coexistence with humans. Understanding how domestication and our presence has shaped dogs' brain capacity to perceive voice and speech is, in fact, the main objective of the Communication Neuroethology Laboratory in which both experts work.
