No Wonder We Feel so Close to Our Dogs—We’re Practically Sharing a Brain!

I simply must talk about the temporal lobes of human and canine brains. (Why, yes, people do sometimes walk away from me in the middle of a conversation at a party. How did you know?) Anyway, back to the brains of dogs and people, which are doing a bunch of their incredible functioning in the same ways and the same places as each other. In other words, there are a lot of similarities in how dogs and people are processing information. 

Reacting to bodies, faces, and objects

Being able to get an accurate picture of people’s faces and bodies is essential for social species. Being able to recognize individuals is necessary for forming and developing relationships. Knowing about another individual’s emotional state, being able to predict their behavior, and understanding their intentions makes life better, easier, safer, and more enjoyable. It’s no surprise that both dogs and people have evolved these critical skills. In a recent study, researchers compared how both species’ brains perform these critical skills by studying how they react to faces, bodies, and inanimate objects.

Knowing where the bodies are buried

Previous work has compared reactions to faces versus inanimate objects, but adding bodies to studies is important because it offers an understanding of how dogs and people react to living, moving entities generally, and not just to faces. Any differences found in the way canine brains react to faces compared to how they react to inanimate objects may only be about living versus non-living stimuli and not about faces specifically, which are treated as a very special category of visual signals.

Facial recognition is tremendously important

Many decades of work have revealed that people have specialized regions of the brain that help them recognize faces and perceive bodies. Other areas of our brain allow us to recognize objects, and it is a serious challenge for people whose face and body recognition brain areas don’t function like most people’s because it is very hard to recognize individual faces with the part of the brain that usually perceives and recognizes objects. That area doesn’t have the ability to tell apart faces to the degree required in social situations because it only needs to tell at a rough scale what things are — it’s a toaster for example, or perhaps it’s a tree.

What the researchers found

In this study, people and dogs were presented with 180 different visual images: dog bodies with the head cropped out, human bodies with the head cropped out, ordinary objects such as a tennis ball and a chair, dog faces, human faces, and scrambled versions of each of these. The scrambled images look like close ups of a section of a pointillism painting. By collecting data from the brain, researchers can tell where the information from these images is being processed. It turns out both species are processing animate objects (people and other animals) in the same parts of the brain. 

Dogs were trained to remain still in an MRI machine

Part of what makes this study so amazing is the way scientists collect data on the dogs and the amount of training it takes to make that possible. This is one of the really cool studies that investigates dogs by training them to stay still in an MRI machine so their brain can be studied — a feat that would not be possible with sedation. (The dogs are free to leave the MRI machine at any time.)

People can obviously be told to hold still, and then they do so. Dogs are also required to stay still inside an MRI machine for long periods of time, which requires lengthy training. The 11 dogs in this study are pet dogs belonging to families who have been trained to lie still in an MRI for many minutes at a time while they are fully awake and not restrained. It would be impossible to do this study if dogs had to be physically restrained or anesthetized because both of those would have profound impacts on their brain that would make it impossible to answer questions about their reactions to seeing various objects. 

Understanding our brains is essential for understanding who we are

Understanding the way brains across species function when dealing with social and cognitive issues is an essential part of understanding the evolution of the brain. That means studies like this help enlighten us about how we (people and dogs) became who we are over evolutionary time. Call me a brain geek all you want (it wouldn’t be the first time!) but I consider that outrageously cool.

It’s well known that both dogs and humans can understand facial expressions and that the matching parts of our brains process this information. This new study shows that dogs have the same ability as humans to process body postures, too. In dogs and in humans, part of the temporal lobe processes the visual perception of body postures. There are similar patterns in our cerebellums and occipital lobes when processing information about faces and bodies, though significant differences in processing faces versus bodies were only found in people. Interestingly, we did not inherit these similar cognitive traits related to visual processing from a common ancestor. Our separate lineages evolved them independently, presumably because similarities in social organization of both dogs and of people requires similar skills.

It’s often said that people and their dogs start to look alike over time, but their brains resemble each other from the moment they meet each other.