Scientists have identified specific brain activity in dogs when they observe human facial expressions. Research involving 14 dogs showed that a part of the brain associated with reward became active when the dogs were shown pictures of happy, smiling human faces.
This reward circuitry is the same area that activates when dogs anticipate a treat or smell a familiar person. Laura Cuaya, a lead researcher from the University of Vienna, explained that this finding suggests happy faces, even from strangers, have a positive value for dogs.
The study also explored how dogs reacted to other human emotions, including anger, fear, and sadness. However, the reward circuitry only responded to happy faces. Raúl Hernández-Pérez, also from the University of Vienna, noted that dogs can differentiate positive emotions from all others, but not between various negative emotions.
The researchers hope their findings will help people communicate more effectively with their dogs. Cuaya suggested that humans should smile at dogs, including unfamiliar ones, as a form of reward.