Dogs tended to turn their heads to the left when they saw human faces expressing anger, fear or happiness. (Photo: Pixabay)
Turns out, dogs can understand what's written all over your face.
A new research conducted by Springer claims that dogs use different parts of their brain to process negative and positive emotions cued by human facial expressions.
For example, if a dog turns its head to the left, it could be picking up that someone is angry, fearful or happy. If there is a look of surprise on a person's face, dogs tend to turn their head to the right.
The heart rates of dogs also go up when they see someone who is having a bad day, said researchers Marcello Siniscalchi, Serenella d'Ingeo and Angelo Quaranta.
The study is the latest to reveal just how connected dogs are with people. The research also provided evidence that dogs use different parts of their brains to process human emotions.
By living in close contact with humans, dogs have developed specific skills that enable them to interact and communicate effectively with people.
Recent studies have shown that the canine brain can pick up on emotional cues contained in a person's voice, body odour and posture, and read their faces.
In this study, the authors watched what happened when they presented photographs of the same two adults' faces (a man and a woman) to 26 feeding dogs.
The images were placed strategically to the sides of the animals' line of sight and the photos showed a human face expressing one of the six basic human emotions: anger, fear, happiness, sadness, surprise, disgust or being neutral.
The dogs showed greater response and cardiac activity when shown photographs that expressed arousing emotional states such as anger, fear and happiness. They also took longer to resume feeding after seeing these images.
The dogs' increased heart rate indicated that in these cases they experienced higher levels of stress.
In addition, dogs tended to turn their heads to the left when they saw human faces expressing anger, fear or happiness.
The reverse happened when the faces looked surprised, possibly because dogs view it as a non-threatening, relaxed expression. These findings, therefore, support the existence of an asymmetrical emotional modulation of dogs' brains to process basic human emotions.
"Clearly arousing, negative emotions seem to be processed by the right hemisphere of a dog's brain, and more positive emotions by the left side," said Siniscalchi.
The results supported that of other studies done on dogs and other mammals. These showed that the right side of the brain plays a more important part in regulating the sympathetic outflow to the heart.
This was a fundamental organ for the control of the 'fight or flight' behavioural response necessary for survival.
The study findings are published in the journal Learning & Behaviour.