Voice link between dogs and humans
Dogs and humans have brains that respond to voices in the same way, scientists have learned.
The same area of the brain activates in both species when they hear a voice - whether it be the human command "sit" or a doggy whine.
Striking similarities were also seen in the processing of emotionally-loaded sounds.
In both humans and dogs, an area near the primary auditory cortex region of the brain lights up more when happy sounds are heard.
Scientists conducting the study trained 11 dogs to lie motionless in a functional magnetic resonance imaging (fMRI) brain scanner.
Their responses to a range of vocal sounds were compared with those of human volunteers. The sounds included whining, crying, playful barking and laughing.
The findings, published in the journal Current Biology, shed light on the special relationship between dogs and humans, say the researchers.
"Dogs and humans share a similar social environment," said lead scientist Attila Andics from the MTA-ELTE Comparative Ethology Research Group in Hungary. "Our findings suggest that they also use similar brain mechanisms to process social information. This may support the successfulness of vocal communication between the two species."
Not surprisingly, the voice area in the brains of dogs was found to respond more to the sounds of other dogs, while humans responded more strongly to human sounds.
There were some differences between the species.
In dogs, 48% of all sound-sensitive brain regions produced a stronger reaction to non-vocal sounds. In humans, only 3% of sound-sensitive regions responded more strongly to sounds other than voices.
The MRI study is the first step towards a greater understanding of the way dogs tune into the feelings of their owners, the scientists claim.
"This method offers a totally new way of investigating neural processing in dogs," said Mr Andics. "At last we begin to understand how our best friend is looking at us and navigating in our social environment."