The brain scans revealed that dogs process smiles in a unique brain region and, for the first time, provided evidence that the animals can distinguish between negative facial expressions. Eight dogs’ brains were scanned while the researchers showed them images of strangers with either a happy or neutral expression. The happy faces lit up the temporal cortex and caudate nucleus in the dogs’ brains - regions associated with higher cognitive and reward processing, respectively. Brain scans showed the dogs did not react in the same brain regions meaning dogs respond uniquely to happiness. In real life, dogs watch human body language, listen to nuances in our voices, and detect information from our scent.