The study focuses on dogs’ brains and their ability to distinguish between familiar and unfamiliar languages. The lead author of the study, neurobiologist Laura Cuaya, conceived the idea for the study when she moved from Mexico to Budapest with her dog Kun-kun.
“We noticed that the people in Budapest were very friendly with dogs and often approached Kun-kun and talked to him,” Cuaya explained to Live Science. “Kun-kun usually pays a lot of attention to people, so I wondered whether he noticed that people in Budapest speak a different language.”
To find out, Cuaya and her team trained Kun-kun and 17 other dogs to lie motionless in an MRI machine so that researchers could successfully scan their brains. While the dogs were being scanned, they listened to three different records: a passage from the well-known children’s book The Little Prince read first in Spanish, then in Hungarian, and then another recording of a series of human noises that do not resemble a spoken language at all. Each dog involved in the study had only been exposed to either Spanish or Hungarian, meaning that one of these languages would be unfamiliar to them.
The scans revealed to the researchers that dogs were able to clearly distinguish between speech and non-speech and that they react differently to familiar and unfamiliar languages. The team assumes that the primary and secondary auditory cortexes, both of which are located within the temporal cortex, allow dogs to process speech in two steps. This process is called the “hierarchy processing,” Cuaya explains. “The primary auditory cortex detects whether a sound is speech or not. Then, the secondary auditory cortex differentiates between a familiar and an unfamiliar language.”
Older dogs demonstrated higher activity in the secondary auditory cortex of the brain, which suggested that they were more skilled at differentiating between familiar and unfamiliar languages than younger dogs. “I think that the main reason [that older dogs are better at differentiating languages] is the amount of exposure to the language,” Cuaya says. “Older dogs have had more opportunities to listen to humans while they talk.”
While researchers believe that other animals are also able to differentiate between languages, dogs are now the only animals known to do so. “The brain is extremely good at picking up patterns, and each language has a series of sounds and patterns that makes them different from each other,” Cuaya points out. “After some training, the brain of many animals should be able to recognize these patterns.”
That said, what makes dogs’ ability to distinguish between human languages is that they don’t have to undergo special training. “Their brains detected the difference spontaneously, perhaps due to the domestication process,” Cuaya adds. “While it is possible that many species can distinguish between human languages, dogs are one of the few that are interested in hearing us.”
Source study: Science Direct – Speech naturalness detection and language representation in the dog brain