Humans use both words and the intonation of speech to decipher the meaning of language, and it turns out that our dogs do, too. In a research paper called “Neural mechanisms for lexical processing in dogs” scientists investigated how dogs process the meaning of language. They found that dogs’ brains have even more in common with humans’ brains than previously thought. (It’s not clear when we will collectively stop being surprised by this, but I hope we always remain excited about new evidence to explain why we feel that dogs are kindred spirits.)
In this study, dogs who have been trained to remain still while their brain activity is recorded listened to recordings of their trainers talking. There were four types of recordings: 1) words of praise spoken with intonation typically associated with praise, 2) words of praise spoken with a neutral intonation, 3) neutral words spoken with intonation typically associated with praise, and 4) neutral words spoken with a neutral intonation.
Researchers analyzed the brain activity of the dogs in response to each of the recordings, and came to several conclusions about the way that dogs respond to words and the intonation of human speech. The dogs processed the vocabulary in the left hemisphere of their brains, which is where humans also process the meaning of words. The dogs processed the intonation of the words separately, in a different region of the brain. Just as humans do, dogs processed the intonation of human speech in the right hemisphere of their brain. Dogs also process sounds that convey emotion without words in this same region of the brain’s right hemisphere.
Dogs process both words and the intonation of human speech to decipher meaning. Just as humans do, they process these two aspects of speech separately, then integrate them to determine the full meaning of what was said. Only the praise that was spoken like praise—higher pitched than normal speech and with more variation in pitch—activated the reward centers of dogs’ brains. Though they may understand words of praise said in any manner, it only makes dogs happy to hear us praise them when we do it with proper feeling.
This research does more than reveal yet another similarity in the way that human and dog brains process information. It also suggests that the ability to connect a word to a meaning did not develop with the evolution of spoken language. Rather, it is a more ancient ability that can be made use of in the context of the human-dog relationship to link specific sounds to specific meanings.
The take away messages from this research are that dogs process two parts of spoken language—words and intonation—the same way that humans do and if you want to make your dogs happy, you have to praise them like you mean it!