We humans are pretty special. We can talk and think and understand each other and do all kinds of things animals can't do, right? Maybe not.
Researchers in Hungary say they have conclusively found that dogs understand and care about not only what we say but how we say it -- and, perhaps more significantly, they do so in pretty much the same way we do.
So, when talking to dogs as when talking to people, it's not just what you say, but how you say it.
Dogs, like people, use the left hemisphere brain region to process words and the right hemisphere to process intonation, the researchers found. The study indicates that the neural mechanisms to process words evolved much earlier than previously thought and that they are not unique to humans.
Dogs didn't develop the physical structures that would have allowed them to form words, but they have the mental capacity to process words and intonations from their human companions, in other words.
Obviously, dogs who live in the wild may not develop this capability, but family dogs who are bathed in words from their humans over time can learn to understand many of them, just as an infant does.
"During speech processing, there is a well-known distribution of labor in the human brain. It is mainly the left hemisphere's job to process word meaning, and the right hemisphere's job to process intonation. 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," said lead researcher Attila Andics of the Department of Ethology at Eötvös Loránd University, Budapest.
"Our findings suggest that dogs can also do all that, and they use very similar brain mechanisms," Andics said.
The researchers trained 13 dogs to lie completely motionless in an fMRI brain scanner, then measured the dogs' brain activity as they listened to their trainers speak.
"Dogs heard praise words in praising intonation, praise words in neutral intonation, and also neutral conjunction words, meaningless to them, in praising and neutral intonations. We looked for brain regions that differentiated between meaningful and meaningless words, or between praising and non-praising intonations," said Anna Gábor, PhD student and one of the authors of the study.
Say it like you mean it
Andics and colleagues also noted that praise activated dogs' reward center - the brain region which responds to all sorts of pleasurable stimuli, like food, sex, being petted, or even nice music in humans. Importantly, the reward center was active only when dogs heard praise words in praising intonation.
"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. 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. Again, this is very similar to what human brains do," Andics said.
The study may help improve communications between dogs and humans. It also has important conclusions about communications among humans.
"Our research sheds new light on the emergence of words during language evolution. What makes words uniquely human is not a special neural capacity, but our invention of using them," Andics said.