There may be a reason why dogs are man's best friend - We have similar brain scans

Friday, March 07, 2014 by: J. D. Heyes
Tags: dogs, brain scans, voice processing

(NaturalNews) Dogs have been called man's (and woman's) best friend, and a new brain-imaging study of dogs indicates one reason why: There are striking similarities in how dogs and humans -- and, perhaps, a number of other mammals -- process voice and emotion.

According to Wired, dogs, like humans, may have brain systems that function similarly in that they are devoted to understanding and processing vocal sounds, and are also sensitive to the emotional content of voices:

These systems have not previously been described in dogs or any non-primate species, and the new findings offer an intriguing neurobiological glimpse into the richness of our particular corner of the animal kingdom.

"What makes us really excited now is that we've discovered these voice areas in the dog brain," said comparative ethologist Attila Andics of Hungary's Eotvos Lorand University, the lead author of the study published Feb. 20 in Current Biology. "It's not only dogs and humans. We probably share this function with many other mammals."

Processing vocal sounds and emotion 'is fundamental to who they are'

That said, human and dogs last shared a common ancestor more than 100 million years ago, say researchers. Therefore, they conclude, if a voice-attuned region could be found in dogs as well, the trait probably runs deeply in shared biology between the two species.

In order to flesh out the possibility, Andics and research teammates trained a half-dozen golden retrievers and five border collies to lay completely still inside a scanner in order to allow scientists to collect fMRI scans of their brains. The scans are able to measure blood flow, which is widely believed to be a good indicator of neural activity. The training process took months, the Los Angeles Times reported, but the dogs retained the knowledge for many months as well.

"They just love it; they can't wait to be the next," Andics told the Times. "I wouldn't believe it if I didn't see it myself."

As further reported by Wired:

Inside the scanner, each of the 11 dogs, and a comparison group of 22 men and women, listened to nearly 200 recordings of dog and human sounds: whining and crying, laughing and barking. As expected, human voice-processing areas responded most to human voices. In dogs, corresponding brain regions responded to the sounds of dogs. In both species, the activity in these regions changed in similar ways in response to the emotional tone of a vocalization -- whining versus playful barking in dogs, for instance, or crying versus laughing human voices.

To anyone who has had a dog as a companion and friend, those results might seem to be somewhat predictable. But watching the process evolve in dogs' brains underscores it.

"It's not a surprising finding, but it's an important finding," cognitive ethologist and author Marc Bekoff, who was not involved in the study, told Wired. Processing vocal sounds and emotion "is fundamental to who they are."

What do dogs hear when humans speak?

Researchers found that responses were not the same between species. In the dogs, vocal processing regions of the brain responded to non-vocal sounds as well. But in humans, they were only triggered by voice, which may have implications in the social trajectory of human evolution, Andics said. He further posited that those areas may have evolved to be more finely tuned for vocal sounds in humans.

But despite the similarities, what differs between dogs and humans is much more extensive. Still, the regions identified in the study have deep evolutionary roots. And though canines might have developed their responses independently of humans, it's much more likely that they were already present in the common ancestor tens of millions of years ago, said Andics. In fact, he suggested that that could be traced back even further in the evolutionary process.

One more question that researchers have yet to answer is what exactly dogs hear when humans speak. The current study did not address that, but scientists have noted that there have been previous observations of common patterns in human and canine vocalizations. And when dogs signal positive emotions, Wired reported, their barking is in short bursts, like human laughter -- and when they are upset, barks are deeper and longer, kind of like moans.

"There are these acoustic rules that convey emotional information, and they seem to be common to species," Andics said.

Sources:

http://www.wired.com

http://earthsky.org

http://www.latimes.com