When Laura Cuaya moved from Mexico to Hungary a few years ago to conduct post-doctoral studies in that country, she took her dog, Kun-kun with her. Until then, she had spoken only Spanish to the dog. She wondered whether Kun-kun would notice that people in Budapest spoke a different language.
Cuaya was aware that studies had shown that human infants, even those who were not yet able to speak, could tell the difference between languages. But dogs?Read More »
Placed in a brain scanner
The animals were trained to lie in a brain scanner without moving. In that way, the team could read the changes in the dogs’ brains as they listened to human speech. They placed headphones on the dogs as they lay in the scanner. They then played them a speech from The Little Prince in Hungarian followed by the same speech in Spanish.
Up to that time, the dogs had heard only one of these languages spoken by their owners, enabling the researchers to compare a language that was highly familiar to a dog with one that was totally unfamiliar to that dog.
As another part of the study, the research team played versions of the speech that were scrambled to determine whether the dogs could detect a difference between non-speech and speech.
After conducting a thorough study of the brain functions of the dogs shown by the scanner, the researchers determined that:
• Dog brains, similar to human brains, are able to distinguish between non-speech and speech.
They found these patterns in the primary auditory cortex of the brain. Their ability to do so might be different from the way in which sensitivity to speech operates in humans, says Raúl Hernández-Pérez, co-author of the study. Whereas brains of humans are particularly tuned to speech, dog brains might react only to the naturalness of the sound, he adds.
• Dog brains can determine the difference between languages.
The researchers found that the ability of dogs to determine the difference between Hungarian and Spanish lay in another part of the brain called the secondary auditory cortex.
An interesting aspect of their findings was that older dogs were able to determine the difference between the unfamiliar and the familiar language better than their younger counterparts. The reason likely is that dogs can pick up on the sound patterns of the language to which they are exposed over the course of the time they spend with humans, says Hernández-Pérez.
Not unique to humans
The findings show that the ability to learn about the patterns of a language is not confined only to humans, says Attila Andics, senior author of the study.
The study failed to show, however, whether this ability is special to dogs or is general among species that are not human. It is possible, Andics adds, that changes that have taken place in the brains of dogs over the tens of thousands of years that they have been living with humans have made them better listeners of human language—although this might not be necessarily so, Andics adds. Future studies will be needed to find out whether this is, in fact, the case.
The study is published in the journal NeuroImage.
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