Dogs perceive human emotions reading facial expressions with the help of various parts their brain to process positive and negative feelings signaled by faces around them.

According to a new study, dogs are able to understand facial expressions on human face. The research exemplified as if a dog moves its head to left, it could understand that someone is angry, happy or fearful. If dogs see an expression of surprise on one’s face, they use to turn their head to right.

Angelo Quaranta, Serenella d’Ingeo and Marcello Siniscalchi from the University of Bari Aldo Moro in Italy reported that the heart rates of dogs also beat faster after seeing somebody having a bad day. The study has been published in the Springer’s Learning & Behavior journal, which is the most recent review on how associated dogs are with humans.

Ph.D. student, Natalia de Souza Albuquerque of University of São Paulo, São Paulo USP said in a statement that, “We still didn’t know if the dogs … can somehow understand that, say, a happy facial expression is positive and a negative facial expression is negative.”

The research also gives evidence that dogs use their different parts of brain to process human feelings. For the same, Marcello Siniscalchi said that, “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.”

“The dogs had to extract the information from the sound, then associate this information with the image, and that involves very complex psychological mechanisms,” Albuquerque added.