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| | Human World on Feb 24, 2014

Dogs and humans use similar parts of brain to listen

The study, which compared fMRI brain scans of dogs and humans, showed that dogs respond most to sounds from other dogs, and humans to the voices of other humans.

Interpreting the cacophony of sounds in our environment is done in specific areas of the brain. For dogs and human, the process is remarkably similar, a new study shows. Using neuroimaging techniques, researchers in Hungary have found that dogs and humans utilize the same region of the brain for interpreting sounds in their environment. They discovered it by comparing fMRI brain scans of dogs and humans listening to different types of sounds. It’s a finding that casts intriguing insights into the unique relationship between two very different species. The scientists published their results in the Feb 20, 2014, issue of Current Biology.

Atilla Andics, of MTA-ELTE Comparative Ethology Research Group in Budapest, Hungary, said in a press release:

Our findings suggest that dogs and humans not only share a similar social environment, but they also use similar brain mechanisms to process social information. This may help the successfulness of vocal communication between the two species.

Canine participants of the study. Image credit: Borbála Ferenczy.

Canine participants of the study. Using positive reinforcement techniques such as praise and treats, the scientists trained the dogs to lie quietly in the fMRI scanner. Image via Borbála Ferenczy.

The auditory cortex, shaded pink, in the human brain. Image credit: Jimhutchins via Wikimedia Commons.

The auditory cortex, shaded pink, in the human brain. Image via Jimhutchins via Wikimedia Commons.

Sounds help us interpret our surroundings. The meanings of those sounds are worked out in a specific area of the brain, called the auditory cortex, in primates such as chimpanzees and humans. Activity in this region of the brain can be observed by running fMRI brain scans on people as they listen to sounds. The scans show that humans are particularly tuned in to the voices of other humans since it’s our main mode of communication.

What if the same sound experiments could be run to look into the inner workings of the brain in non-primates? Dogs, a sub-species of Canis lupus that has been shaped by its close relationship with humans over tens of thousands of years, seemed an ideal test case: they respond to people’s voices and could be trained to calmly tolerate fMRI scans.

Using positive reinforcement techniques, the scientists trained several dogs to lie quietly in the fMRI scanner. One of the dogs had undergone the procedure many times before, and was already comfortable with being strapped in the scanner bed, and staying calm and motionless during the scanning process. While scientists and dog trainers lavished praise and treats on him, the other dogs watched. They got the message: sitting in that strange machine was fun and rewarding.

Strapped in for a scan. Image credit: Eniko Kubinyi.

Strapped in for a scan. Scans showed that dogs and humans process sounds at similar locations in the brain, with dogs being more responsive to sounds from other dogs. Image via Eniko Kubinyi.

In the experiments, dog and human subjects listened to the sounds made by other dogs and humans, sounds that signaled negative emotions like whining and crying, as well as happy sounds of playful barking and laughter.

The scans showed that dogs and humans processed sounds at similar locations in the brain. Dogs were more responsive to sounds from other dogs, while humans reacted more strongly to the voices of other humans. The researchers also noticed a similarity in how both humans and dogs reacted to sounds that elicited certain emotions, such as distress and happiness; for both species, a particular area near the primary auditory complex showed higher activity levels when responding to happy sounds versus unhappy ones.

Dogs, however, seemed more responsive to non-vocal sounds. fMRI scans showed that 48% of sound-sensitive brain regions lit up in response to non-vocal noise, compared to just 3% in humans. That could explain why dogs are such good … watchdogs.

Andics commented that these studies are a first step to understanding why dogs are able to respond so well to the emotions of their human companions. He said:

This method offers a totally new way of looking at neural processing in dogs. At last we begin to understand how our best friend is looking at us and navigating in our social environment.

Waiting to be scanned. Image Credit: Eniko Kubinyi.

Waiting to be scanned. For both dogs and humans, a particular area near the primary auditory complex showed higher activity levels when responding to happy sounds versus unhappy ones. Image via Eniko Kubinyi.

Bottom line: Dogs and humans utilize the same region of the brain for interpreting sounds in their environment. This discovery, made by scientists in Hungary, was uncovered when they compared fMRI brain scans of dogs and humans listening to different types of sounds. The scientists published their results in the Feb 20, 2014, issue of Current Biology.