How a Dog's Brain Processes Human Faces

New research using fMRI shows the bilateral temporal cortex plays a key role.

Posted Mar 04, 2016

Dogs have a special social relationship with humans that reveals itself in various ways. Of course, depending on the autobiography of a particular individual, his or her own relationship with humans will vary, so that while many dogs consider humans to be their "best friend," not all dogs are unconditional lovers. Regardless, because of the long association with humans during the process of domestication, dogs have the potential to display behavior patterns that are related to their relationship with humans (please also see "Dog Behavior: An Encyclopedic Review of What we Know" for a review of Dr. Adam Miklosi's excellent book Dog Behaviour, Evolution, and Cognition). Dogs also pay a good deal of attention to human faces, and I'm pleased to inform you about a new study, available online, that has discovered the parts of the dog's brain that are responsible for processing our faces. 

Researchers Laura V. Cuaya, Raúl Hernández-Pérez, and Luis Concha have recently published an essay called "Our Faces in the Dog's Brain: Functional Imaging Reveals Temporal Cortex Activation during Perception of Human Faces" in the journal PLOS One for which the abstract reads:

Dogs have a rich social relationship with humans. One fundamental aspect of it is how dogs pay close attention to human faces in order to guide their behavior, for example, by recognizing their owner and his/her emotional state using visual cues. It is well known that humans have specific brain regions for the processing of other human faces, yet it is unclear how dogs’ brains process human faces. For this reason, our study focuses on describing the brain correlates of perception of human faces in dogs using functional magnetic resonance imaging (fMRI). We trained seven domestic dogs to remain awake, still and unrestrained inside an MRI scanner. We used a visual stimulation paradigm with block design to compare activity elicited by human faces against everyday objects. Brain activity related to the perception of faces changed significantly in several brain regions, but mainly in the bilateral temporal cortex. The opposite contrast (i.e., everyday objects against human faces) showed no significant brain activity change. The temporal cortex is part of the ventral visual pathway, and our results are consistent with reports in other species like primates and sheep, that suggest a high degree of evolutionary conservation of this pathway for face processing. This study introduces the temporal cortex as candidate to process human faces, a pillar of social cognition in dogs.

Dogs are unique in being able to recognize and attend to human faces without training

This essay has received a good deal of attention in popular media and a video of what they did and what they learned can be seen here. The authors also write, "The recognition of human faces in dogs may have been a crucial factor for their adaptation, given their natural anthropogenic niche, as some dogs can have more contact with human faces than with other dogs’ faces [12]. The recognition of human faces by dogs could be an essential factor for establishing attachment with humans. This is supported by the evidence found so far, that dogs, and no other canids, are able to recognize and attend to human faces without training [11]." They also note, "Dogs have a predisposition to cooperate with humans [6] that, combined with non-invasive methodologies, make a perfect marriage for their use as a model." (The numbers refer to references in the online essay.)

The results of this study on social cognition are very important and I hope to see more of these sorts of non-invasive studies in the future. Comparative research will be most welcomed and will shed light on how our close relationship with dogs has shaped the ways in which their brains process faces and other social stimuli.

Marc Bekoff's latest books are Jasper's Story: Saving Moon Bears (with Jill Robinson), Ignoring Nature No More: The Case for Compassionate Conservation, Why Dogs Hump and Bees Get Depressed: The Fascinating Science of Animal Intelligence, Emotions, Friendship, and Conservation, Rewilding Our Hearts: Building Pathways of Compassion and Coexistence, and The Jane Effect: Celebrating Jane Goodall (edited with Dale Peterson). (Homepage: marcbekoff.com; @MarcBekoff)