Dogs are able to understand the emotions behind an expression on a human face. For example, if a dog turns its head to the left, it could mean that someone is angry, anxious, or happy. When there is a look of surprise on someone's face, dogs tend to turn their heads to the right. Dogs' heart rates also rise when they see someone having a bad day, say researchers at the University of Bari Aldo Moro in Italy. The research is the latest to reveal how connected dogs are to people. The study also provides 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 allow them to interact and communicate with humans in an efficient way. Recent studies have shown that the dog's brain can pick up on emotional signals in a person's voice, body odor and posture and read their faces.
In this study, the authors looked at what happened when they presented pictures of the faces of the same two adults (a man and a woman) to 26 eating dogs. The images were strategically placed on the sides of the animals' line of sight and the photos showed a human face expressing one of six basic human emotions:anger, fear, happiness, sadness, surprise, disgust or being neutral.
The dogs showed greater response and heart activity when they showed pictures that expressed exciting emotional states, such as anger, fear and happiness. They also needed more time to continue eating after seeing these images. The increased heart rate of the dogs indicated that they experienced a higher degree of stress in these cases.
In addition, dogs tended to turn their heads to the left when they saw human faces displaying anger, fear, or happiness. The reverse happened when the faces looked surprised, possibly because dogs see it as a non-threatening, relaxed expression. These findings therefore support the existence of an asymmetric emotional modulation of the canine brain to process fundamental human emotions.
The results also support those of other studies conducted on dogs and other mammals. These show that the right side of the brain plays a more important role in regulating sympathetic outflow to the heart. This is a fundamental organ for controlling the fight-or-flight behavioral response necessary for survival.
