Thousands of years of domestication have endowed dogs with a unique ability to comprehend human speech, and new research suggests that their brains can even distinguish between languages. The latest study, published in the journal NeuroImage, is the first to uncover such a skill in a non-human animal. The researchers trained 18 canines to lie immobile within a functional magnetic resonance imaging (fMRI) scanner so that their brain activity could record as they listened to human speaking audio recordings. Two of the dogs in the study came from homes where the only language was spoken was Spanish, while the other 16 came from Hungarian-speaking families.
Each dog listened to an extract from Antoine de Saint-The Exupéry’s Little Prince in both Spanish and Hungarian while in the scanner. They also heard jumbled-up versions of these recordings that made no sense and sounded strange. The researchers discovered that activity patterns inside the dogs’ primary auditory cortex altered depending on whether they heard the actual speech or jumbled gibberish when studying their brain reactions to these recordings. This implies that dogs, regardless of the language spoken, can tell the difference between speech and non-speaking.
This finding, according to research author Ral Hernández-Pérez, is more likely to reflect dogs’ ability to “sense the naturalness of the sound” than their ability to recognize human speech per se. Based on this discovery, the researchers compared brain activity patterns in dogs listening to recordings in their native language against recordings in a foreign language. These language-specific patterns were discovered in a different part of the brain called the secondary auditory cortex, implying that “separate cortical regions facilitate speech naturalness recognition and language encoding in the canine brain.”
The researchers also discovered that older dogs had a stronger brain reaction to language, leading them to believe that more exposure to human voice allows pets to improve their linguistic recognition skills. Furthermore, similar activity patterns were stronger in longer-headed dogs, implying breed variations in how they perceive human speech.
The findings show that “the potential to learn about the regularities of a language is not exclusively human,” according to research author Attila Andics. However, it is unclear “whether this capacity is unique to dogs or common to all non-human creatures.” “It’s possible that the brain changes that have occurred over the thousands of years that dogs have lived with people have made them better language listeners, but this isn’t always the case. This will have to be determined in future research.”
