The Family Dog Project say the ability to process words is older than previously though
A new study has found dog brains process both what people say and how we say it.
Dogs, like people, use the left hemisphere of their brain to process words and the right hemisphere to process intonation.
The Family Dog Project found that praising a dog activates their brain's 'reward centre' only when both words and intonation match.
It suggests dogs can not only tell apart what we say and how we say it, but also combine the two - for a correct interpretation of what those words mean.
The findings suggest mechanisms to process words evolved much earlier than previously thought, and they are not unique to the human brain.
It shows that if an environment is rich in speech, as is the case of family dogs, word meaning representations can arise in the brain.
"During speech processing, there is a well-known distribution of labour 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," lead researcher from Budapest's Eötvös Loránd University Attila Andics says.
"But the human brain not only separately analyses what we say and how we say it, but also integrates the two types of information, to arrive at a unified meaning.
"Our findings suggest that dogs can also do all that, and they use very similar brain mechanisms."
The researchers trained 13 dogs to lay completely still in a fMRI brain scanner.
"We measured dogs’ brain activity as they listened to their trainer’s speech," PhD student and author of the study Anna Gábor says.
"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."
The images showed dogs prefer to use their left hemisphere to process meaningful, but not meaningless, words.
Dogs activate a right hemisphere brain area to tell apart praising and non-praising intonation.
The study found this was the same brain region that researchers previously found in dogs for processing emotional non-speech sounds from both dogs and humans.
This suggests that intonation processing mechanisms are not specific to speech.
Researchers say this study is the first step to understanding how dogs interpret human speech, and these results can also help to make communication and cooperation between dogs and humans more efficient.