“In addition to speech detection, dog brains could also distinguish between Spanish and Hungarian,” say researchers.

A new brain imaging study conducted by experts from the Department of Ethology at Eötvös Loránd University (Hungary) reveals that dog brains can recognize speech and exhibit different activity patterns when exposed to a familiar and unfamiliar language.

This is the first time that a non-human brain has been shown to be able to distinguish between two languages.

This research has been published in the journal NeuroImage.

“Some years ago I moved from Mexico to Hungary to join the Neuroethology of Communication Lab at the Department of Ethology, Eötvös Loránd University for my postdoctoral research. My dog, Kun-kun, came with me. Before, I had only talked to him in Spanish. So I was wondering whether Kun-kun noticed that people in Budapest spoke a different language, Hungarian,”

“We know that people, even preverbal human infants, notice the difference. But maybe dogs do not bother. After all,

Kun-kun and 17 other dogs were trained to lay motionless in a brain scanner, where we played them speech excerpts of The Little Prince in Spanish and Hungarian. All dogs had heard only one of the two languages from their owners, so this way we could compare a highly familiar language to a completely unfamiliar one. We also played dogs scrambled versions of these excerpts, which sound completely unnatural, to test whether they detect the difference between speech and non-speech at all,” said Laura V. Cuaya, first author of the study.

When comparing brain reactions in dogs to speech and non-speaking, researchers discovered unique activity patterns in the primary auditory cortex of the dogs. This disparity existed independently of whether the stimuli came from a language that was familiar to the subject or one that was new to him. The researchers found no evidence that dog brains have a neurological preference for speech over non-speaking, despite the fact that they were exposed to both.

But the mechanism underlying this speech detection ability may be different from speech sensitivity in humans: whereas human brains are specially tuned to speech, dog brains may simply detect the naturalness of the sound” — explained Raúl Hernández–Pérez, coauthor of the study.

These language-specific activity patterns were found in another brain region, the secondary auditory cortex. Interestingly, the older the dog was, the better their brain distinguished between the familiar and the unfamiliar language. “Each language is characterized by a variety of auditory regularities. Our findings suggest that during their lives with humans, dogs pick up on the auditory regularities of the language they are exposed to,” added Hernández–Pérez. 

It is exciting, because it reveals that the capacity to learn about the regularities of a language is not uniquely human. Still, we do not know whether this capacity is dogs’ specialty, or general among non-human species. Indeed, it is possible that the brain changes from the tens of thousand years that dogs have been living with humans have made them better language listeners, but this is not necessarily the case. Future studies will have to find this out,” concluded Attila Andics, senior author of the study. 

“And if you wonder how Kun-kun is doing after moving to Budapest: he leaves just as happily as he lived in Mexico City – he saw snow for the first time and he loves swimming in the Danube. We hope that he and his friends will continue to help us uncover the evolution of speech perception” said Cuaya.

Source: 10.1016/j.neuroimage.2021.118811

Image Credit: Eniko Kubinyi

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