How Dogs View the World: Brain Scans Tell Us What They See
Dogs recognize human facial expressions, and now we know how they do it.
Posted April 14, 2018
Research has clearly shown that dogs have rich and deep cognitive and emotional lives. And now a new study using functional Magnetic Resonance Imaging (fMRI) shows us what a dog is looking at. An essay published by Chris Baraniuk in New Scientist — "Dog brain scans show if they are looking at a happy or sad face" — summarizes an unpublished manuscript by Raúl Hernández-Pérez, Luis Concha, and Laura V. Chaya titled "Decoding Human Emotional Faces in the Dog’s Brain," in which readers can find out more about the methods that were used, the results, and research that has been done by others. (For more about what it means to have a preprint of an essay published online, click here).
The essay by Baraniuk was intriguing enough for me to publish this brief piece about what Hernández-Pérez and his colleagues discovered. Baraniuk's essay is only available to subscribers, so I'll summarize what he wrote, and say a bit more about Hernández-Pérez and his colleagues' manuscript.
The researchers studied four border collies who were shown happy, sad, angry, or fearful faces made by unfamiliar humans. They discovered that simply by looking at brain scans that were generated by the whole brain, they could tell which facial expressions the dogs saw. To wit, "seeing a person with a happy face produced a particularly distinctive pattern of brain activity, particularly in the temporal cortex on the side of the brain. This part of the brain is thought to be involved in processing complex visual information, including faces, in humans and animals including dogs, primates, and sheep." The researchers report: "Happy faces induce a specific signature of cortical activity that makes it possible to discriminate it from other emotions." They also discovered that it was much harder to distinguish between anger and sadness, often called negative emotions.
Dogs and humans process emotions similarly
What also was intriguing was how similar the dogs' brain activity was to scans of human brains when people were looking at different facial expressions. Barnard College dog researcher Alexandra Horowitz thinks of dogs as "canine anthropologists" who are adept at reading our emotions, most likely because of the long period of time they've lived alongside us. Similarly, Hernandez-Pérez and his colleagues note, "Our results show that human emotions are specifically represented in dogs’ brains, highlighting their importance for inter-species communication."
Despite the small sample size, this research is an important step not only for conducting noninvasive neuroimaging studies on dogs (and other animals), but also for determining just how similarly dogs and humans process the different emotions displayed by facial expressions. Emory University researcher Gregory Berns and his colleagues have also conducted a number of very interesting studies using noninvasive neuroimaging on dogs. (For an interview with Berns about his book, What It's Like to Be a Dog: And Other Adventures in Animal Neuroscience, please click here.) Adam Miklósi and his colleagues at Hungary's Eötvös Loránd University also are conducting this type of research.
Please stand by for forthcoming comparative research on the ways in which noninvasive neuroimaging can help us see how nonhuman animals sense their worlds. It will be interesting to learn not only how similar they are to humans, but also about those brain patterns that are species-specific and reflect adaptations that are unique to a given species or group of species. What an exciting time it is to be interested in the neural bases of cognitive and emotional capacities.
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