Dog lovers already know that a kindly word means a lot to the family pet, but researchers now understand why.
The amazing communication between humans and man's best friend has been the subject of scientific work for years, as dogs have had thousands of years to learn what their owners want and mean. Research in 2014 showed dogs rely on intonation to separate speech components, allowing them to understand what owners mean by, "Let's go for a walk," but that study could not show how the speech was being processed in the canine brain.
New research from Hungary, published in the journal Science, studied the brain activity of dogs as they interpreted human speech. Scientists found the canine brain processes speech using both sides of the brain: The meaning of words activates the left side of the brain, while the tone goes through the right hemisphere. This not only clarifies what is happening inside a dog's brain when someone is speaking, as The Washington Post reported, it shows the dog's brain is working to process speech in much the same way as its owners.
The researchers were interested to find that canine brains process speech in a manner so similar to humans, reported the Agence France-Press. Their hope is that this knowledge can help humans to improve communication with man's best friend.
"The human brain not only separately analyzes what we say and how we say it, but also integrates the two types of information, to arrive at a unified meaning," lead researcher Attila Andics told AFP. "Our findings suggest that dogs can also do all that, and they use very similar brain mechanisms."
This means that to really understand the meaning, as dog lovers already know, the dog needs consistency in word and tone.
“It shows that for dogs, a nice praise can very well work as a reward, but it works best if both words and intonation match,” said Dr. Andics in a statement. “So dogs not only tell apart what we say and how we say it, but they can also combine the two, for a correct interpretation of what those words really meant.”
To determine this, the Hungarian researchers and colleagues at Eötvös Loránd University in Budapest trained a collection of family-owned golden retrievers and border collies to sit quietly inside an MRI scanner. With the scanner monitoring brain activity, a trusted trainer issued compliments such as "clever" and "that's it" in both a warm tone and a flat tone.
Unrestrained and resting, the dogs' brains processed the words regardless of tone, with the words' meaning going to the left brain and the tone going to the right, the Associated Press reported. Only when they matched, however, did the brain's "reward" center express the same sort of excitement seen after physical rewards such as food, sex, or a good ear scratch.
"Dog brains care about both what we say and how we say it," Andics told AP. "Praise can work as a reward only if both word meaning and intonation match."