We all know that in humans, specific areas of the brain are used for face processing. Until now, it was difficult to tell how face perception worked in dogs. Mexican researchers recently analyzed the specific brain areas in dogs that allow them to perceive human faces: an opportunity to test whether the saying “dogs are a man's best friend,” is actually true.

The study conducted by Laura V. Cuaya, Raùl Hernandez-Perez and Luis Concha, published in Plos One, focuses on describing the brain correlates in dog of perceiving human faces using functional magnetic resonance imaging (fMRI). Before the study began, the 7 dogs (4 males and 3 females, from 15 to the 30 months old: 5 border collies, a Labrador retriever and a golden retriever) were familiarized with the MRI. Using a fake scanner and over the course of 4 months, the dogs were accustomed to staying still in a Sphinx position with their heads resting on a chin rest.

Following this training phase, the scientists showed the dogs either 50 photos of “neutral” human faces or 50 photos of everyday objects. The images were presented on a screen during single sessions lasting 190 seconds in sequences of 5 images displayed for 7 seconds. During the viewing, brain activity was recorded for subsequent analysis.

When viewing human faces, the dogs' brain activity changed considerably in several brain areas, mainly the bilateral temporal cortex. The contrasting photo condition (everyday objects) elicited no significant changes. This temporal cortex is part of the ventral visual pathway and, according to researchers, appears to be a pillar of social cognition in dogs. The scientists also showed that the brain patterns related to face perception included activity in the caudate nucleus, an area associated with reward.

According to the authors, it seems likely that for dogs, seeing a human face is more intrinsically related to reward than seeing an object.