Like Humans, Dogs Understand Both Tone and Vocabulary

When we talk to our dogs, it turns out they’re listening pretty carefully. According to a study in the journal Science, dogs listen to both vocabulary and tone of voice, processing them together. That means your beloved pup is paying attention both to what you say and how you say it.

The New York Times reports that Hungarian scientists recently trained a group of 13 extremely patient dogs to lie completely still in a MRI machine while the researchers measured brain activity. Scientists then played a voice recording of a trainer saying positive phrases (like “good boy”) in a positive tone of voice, positive phrases in a neutral tone of voice, neutral words (like “however”) in a positive tone of voice, and neutral words in a neutral tone of voice.

They found that the reward centers in the canine volunteers’ brains lit up significantly more when they heard positive phrases in a positive tone. Positive phrases in a neutral tone and neutral phrases in a positive tone didn’t have nearly the same impact. That is, dogs interpreted tone and vocabulary together. (Researchers note that in cases where dogs respond to owners saying meaningless or insulting words in a positive tone of voice, the dogs are likely responding to body language.)

The team also found that dogs put more stock in words than intonation: While the left hemisphere of the brain is largely responsible for interpreting the meanings of words, the right is responsible for interpreting intonation. Looking at the MRI results, researchers observed a left hemisphere bias for processing meaningful words independently of intonation—a bias humans also share.

The discovery is significant, in part, because it shows that dogs—and possibly other animals—process language in much the same way as humans. They not only interpret both tone and vocabulary together, but share a left hemisphere bias when it comes to communication.

"Humans seem to be the only species which uses words and intonation for communicating emotions, feelings, inner states," researcher Attila Andics tells NPR. "To find that dogs have a very similar neural mechanism to tell apart meaningful words from meaningless sound sequences is, I think, really amazing."

For more on the study from the authors themselves, check out the video below.

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