Dogs can read human emotions through facial expressions, study finds

A peek inside dogs' brains revealed man's best friend can distinguish emotions in people's faces, researchers at the University of Vienna have found, providing what they said was the first ever evidence of such an ability.

In the study, researchers used machine learning to analyse brain scans of 12 dogs as the animals viewed images of human faces displaying different emotions, the university said in a press release on Tuesday.

Researchers found that brain regions linked to higher cognitive functions and reward processing — the temporal cortex and caudate nucleus — were activated only by images of happy strangers.

Anger, fear and sadness did not trigger those regions, according to the study, published in Cell Press journal iScience on Monday.

However, when the researchers looked at the whole brain, they found distinct activity patterns that differentiated fear from anger and sadness, providing the first evidence that dogs can tell apart specific negative facial expressions.

Dogs "have evolved with us to understand our expressions and cooperate with us, and recognising that can change how we communicate with and care for them," senior author Laura Cuaya said.

The researchers next plan to investigate how dogs integrate other cues, including body language, voice nuances and scent, to interpret the humans around them.

They also hope to compare how human and canine brains process the same emotional signals.

The researchers added that participants in the study were all pets from loving families and cautioned that dogs outside such environments may respond to human emotional cues differently.

-Reporting by Linda Pasquini, Editing by Miranda Murray and Sharon Singleton/Reuters