We have reported in the past on a study that was taking place to identify whether dogs understand human emotions. The authors of this study report that there is a tendency in dogs to turn their head towards the left when you express anger, fear or happy emotions, and to the right if you look surprised. Additionally, dogs displayed higher heart rates and emotional activity when shown photos of humans in a high emotional state.
These results demonstrate some indication that dogs are sensitive to human faces, which supports the theory that canine brains can process basic human emotions. Which, let’s be honest, we secretly knew all the time!