Petting a dog has a curiously therapeutic effect on the brain, study finds

It’s well known that dogs profoundly benefit our mental health as well as provide emotional support. But our pets might also help our brain in other surprising ways, according to new research.

Scientists analyzed the impact of petting a dog on the brain’s prefrontal cortex, revealing findings that could one day improve animal-assisted therapy treatments for humans. The findings were published Wednesday in the journal PLOS ONE.

Here’s the background — The brain’s prefrontal cortex plays a vital role in processing emotions and regulating tasks related to executive functioning, such as attention, working memory retention, and problem-solving. Researchers wanted to know how this part of the brain would respond to interacting with a dog, which are among the most common pets in animal-assisted therapies.

“We decided to start this study because little is known about the brain's reaction to interaction with animals,” Rahel Marti tells Inverse. Marti is the lead author of the study and a researcher in the University of Basel’s psychology department.

Marti’s research team analyzed how 21 volunteers’ frontal cortexes activated in response to contact with either a dog or a stuffed animal in comparison to neutral activity like looking at a blank wall. The researchers measured their brain activity using a method known as near-infrared spectroscopy, which is a non-invasive way to calculate oxygen saturation in the brain. It also has advantages over other brain imaging methods like fMRIs, since participants can sit in a normal room and feel more at ease.

In sessions involving the stuffed animal, researchers placed the plush creature on the participant’s thigh for them to view, and they were later able to pet the toy. Similarly, the dog would lie down on the couch, touching the participant, and, in a subsequent session, the participant was allowed to pet the animal.

What they found — The research yielded two key findings that provide striking insight into the impact of a dog on the human brain.

First: Brain activity in the prefrontal cortex increased when participants had closer contact with either the stuffed plushie or the living dog.

“Our result confirms previous studies linking closer contact with animals or control stimuli with increased brain activation,” Marti says.

But the second finding was even more compelling: The study participants experienced higher brain activity when petting the dog versus interacting with the stuffed animal. This is in line with previous studies on horses and cats, but it’s the first to document increased human brain activity when interacting with canines.

“What's new here is that we looked at different interactions: Watching, feeling, and petting,” Marti adds.

Why it happened — While brain activity decreased between the first and the second interactions participants had with the stuffed animal, the opposite occurred with the dog — a result that surprised the scientists. While we can’t say for certain why brain activity increased over time while petting the dog, researchers have a hunch.

“Our explanation is that the participant established a bond with the dog,” Marti says.

That bond likely gave participants an emotional investment in the animal, leading to greater attention — indicated by higher activity in the prefrontal cortex — when petting the dog compared to the stuffed animal. Prior research shows that animals can improve attention in humans, likely by increasing their emotional engagement — for example, a human is more likely to think about a dog’s feelings when petting them.

“We think emotional involvement might be a central underlying mechanism of brain activation in human-animal interactions,” Marti explains.

Why it matters — The paper suggests that petting a dog can engage our emotions and our attention in a way that non-living stimuli — like stuffed animals — cannot.

It’s possible dogs could help patients who have difficulty paying attention in social situations, particularly individuals who show higher levels of emotional engagement and brain activity when interacting with pups. Therapy dogs are already being used in medical settings for pain management and other purposes.

“Our results might be relevant for therapy with patients with deficits in motivation, attention, and socioemotional functioning, Marti says, adding “such activities could increase the chance of learning and of achieving therapeutic aims.”

What’s next — Further research will need to confirm and build upon Marti’s research before therapy dogs can help people with attention deficits. Future research could focus on whether all participants benefit from increased emotional engagement and attention when petting pups, or whether this finding only applies to humans who already like dogs.

“This study is just a first step,” Marti says.