A new study has shown the special effect of a human smile on the brain of dogs. Experts from the University of Vienna found increased activity in the reward area. A similar reaction in animals is caused by food, praise, or meeting a familiar person. The experiment involved fourteen dogs, whose brains were scanned during the demonstration of emotions. Joyful faces elicited a special reaction that was not provoked by anger, fear, or sadness. This indicates that dogs don't just recognize changes in human facial expressions. Animals are able to attach positive value to the very sight of a smiling face.

Previous work has already linked this same area of the canine brain to the expectation of food. This zone was also activated when the animals recognized familiar smells. Lead researcher Laura Kuaya commented on the specifics of the detected reaction. Happy faces act as a positive incentive for dogs, even when a stranger smiles. The joy on a stranger's face also has a positive value for the animal. At the same time, dogs confidently distinguished joyful facial expressions from negative ones. However, the researchers did not find evidence of reliable differences between individual negative emotions. Animals did not always consistently share anger, fear, and sadness with each other.

According to scientists, the revealed ability of dogs is associated with a long process of domestication. Over thousands of years of living next to humans, animals have developed subtle signal-reading mechanisms. Dogs have learned to understand human social signals more precisely in everyday communication. A joyful facial expression became an independent positive incentive for them. A small sample of fourteen dogs remains a limitation of this scientific work. Additional experiments with a large number of animals will be required to confirm the findings. The results of the study expand the scientific understanding of the emotional connection between humans and dogs. So, a smile acts as an important social signal when communicating with a pet.