After recently reports that dogs can distinguish as many as 89 different words, a completely different research team has learned that dogs can tell the difference between various human languages. The same research determined that dogs can also differentiate between random sounds and language, and that the older the dog, the better they are at each of these skills.
BACKGROUND: DOGS ALREADY GOOD AT UNDERSTANDING HUMANS
Dogs can be trained to respond to verbal commands in any language, and many seem to know the sound of a can opener from miles away. Previous research has shown that this ability includes deciphering as many as 89 different words spoken by a human caregiver, regardless of the language spoken by said human.
Now, this latest research looks at how a dog’s brain reacts to the sound of different human languages as well as non-language ‘gibberish,’ especially dogs who have been raised around humans speaking only one language.
ANALYSIS: HOW DO YOU SAY BELLY RUBS IN HUNGARIAN?
“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,” says Laura V. Cuaya, first author of the study published in the journal Neuroimage. “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.”
To test the hypothesis, Cuaya and her colleagues trained Kun-Kun and 17 other dogs to sit still in a brain scanner while wearing headphones and listening to different audio tracks. Like Kun-kun, all of the dogs had only been exposed to one language during their lives, either Spanish or Hungarian.
Once inside the brain scanner, each dog was played three sets of audio tracks. First the cooperative canines heard words spoken in the language they were familiar with. Second, each dog heard those same phrases again, only this time in the unfamiliar language. Finally, each dog was played a remixed version of the phrase in their familiar language but scrambled in a way that was abnormal for human speech.
As expected, the dogs’ brain scans showed that they recognized the familiar language and not the unfamiliar one. Also, the dogs’ brains reacted completely differently to the scrambled speech, meaning they somehow noted it was not actual language.
“Dog brains, like human brains, can distinguish between speech and non-speech.,” said study co-author Raúl Hernández-Pérez in the press release announcing the results. “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.”
The researchers also noted that the older the dog, the better they were at distinguishing between languages.
“Each language is characterized by a variety of auditory regularities,” said Hernández-Pérez. “Our findings suggest that during their lives with humans, dogs pick up on the auditory regularities of the language they are exposed to.”
OUTLOOK: DOGS MAY NOT BE THE ONLY ONES WITH THIS ABILITY
The researchers note that this ability may be connected to the close relationship developed between humans and canines over the last ten thousand plus years of domestication. However, they don’t rule out the possibility that other animals may also be able to differentiate between human languages.
“We do not know whether this capacity is dogs’ specialty, or general among non-human species,” said Attila Andics, senior author of the study. “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.”
Finally, for those wondering how Kun-kun is doing after moving to Budapest, Cuaya says, “he lives just as happily as he lived in Mexico City – he saw snow for the first time, and he loves swimming in the Danube.”
Of course, ever the scientists, Cuaya also noted, “We hope that he and his friends will continue to help us uncover the evolution of speech perception.”