That dogs can sense and sometimes respond to changes in human emotion is so established that, well, the dogs on the street know it.
But in what is being touted as a first, scientists at the University of Vienna have come up with evidence that not only can dogs perceive if a person is happy or sad, but "can distinguish between negative facial expressions” indicating anything from rage to melancholy to fright.
Published by Cell Press, the findings were the result of a series of scans of dogs’ brains as they were shown a range of human expression. The imaging showed that dogs process smiles in one brain region and the gamut of frowns and grimaces in another, according to the team.
"The biology behind this ability had been largely unexplored until now,” the researchers say. They explain that the sight of happy humans "lit up the temporal cortex and caudate nucleus in the dogs’ brains.”
The brain sections in question are "associated with higher cognitive and reward processing,” according to the researchers. They point out that the negative expressions did not spark the same response.
"The activity in the caudate nucleus is particularly interesting,” says Laura Cuaya of the University of Vienna. "Happy human faces” could have some "emotional significance" for dog, she adds.
The researchers caution that findings based visual perception likely do not tell the full story about canine emotions, given that dogs’ senses – particularly smell and hearing, which far exceed human capabilities – play a part in how they take in their surroundings.
Prior research has shown dogs as able to predict if a person is about to have a seizure or even detect the onset of disease before a medical diagnosis.
Other research, however, has shown dog owners often failing to reciprocate. Most people misunderstand behaviour such as clinginess, which is often a dog signalling pain rather than showing affection.
Other tests have found people similarly tending to project human traits onto dogs when trying to interpret gestures. – dpa
