It turns out that dogs really do understand human language, according to new research.
They process spoken word in a similar way to humans, and in the same area of the brain, say scientists.
This explains why dogs get so excited when we say ‘walk’ or ‘treats’, or respond to an affectionate tone of voice.
For the research, a dozen dogs were trained to lie in an MRI scanner so their grey matter could be monitored as toys were held aloft.
Different areas of the brain lit up when the US team either used the correct words to describe them or spoke gibberish.
Neuroscientist Professor Gregory Berns, of Emory University, Atlanta, Georgia, said: ‘Dogs may have varying capacity and motivation for learning and understanding human words.
‘But they appear to have a neural representation for the meaning of words they have been taught, beyond just a low-level Pavlovian response.’
The study, published in Frontiers in Neuroscience, shows for the first time that dogs have at least a rudimentary neural representation of the meaning of words they have been taught.
They can tell the difference between those they have heard before from those they have not.
First author Ashley Prichard, a PhD candidate in Prof Bern’s psychology lab, said: ‘Many dog owners think their dogs know what some words mean, but there really isn’t much scientific evidence to support that.
‘We wanted to get data from the dogs themselves – not just owner reports.’
The researchers focused on questions surrounding the brain mechanisms dogs use when a human speaks – or even what constitutes a word to them.
Senior author Gregory said: ‘We know dogs have the capacity to process at least some aspects of human language since they can learn to follow verbal commands.
‘Previous research, however, suggests dogs may rely on many other cues to follow a verbal command such as gaze, gestures and even emotional expressions from their owners.’
He is founder of the Dog Project, which is researching evolutionary questions surrounding man’s best friend.
The project was the first to train dogs to voluntarily enter a functional magnetic resonance imaging scanner and remain motionless, without restraint or sedation.
Gregory says the brain of a medium-size dog, like a labrador, is about the size of a lemon.
His inspiration was the mission that killed Osama Bin Laden, in which a military dog jumped out of a helicopter.
He says: ‘That was my epiphany. If a dog can be trained to jump out of a helicopter, certainly we can train a dog to go in an MRI.’
Using toys to keep the dogs comfortable in the MRI, the test started by saying the names of the toys at set intervals.
Eddie, a golden retriever-Labrador, for instance, heard ‘Piggy’ or ‘Monkey,’ before the matching toy was held up.
As a control, the owner then spoke gibberish, such as ‘bobbu’ and ‘bodmick,’ then held up novel objects like a hat or a doll.
The results showed greater activation in auditory regions of the brain to the new ‘pseudowords’, relative to the trained words.
Ashley explained: ‘We expected to see dogs neurally discriminate between words that they know and words that they do not.
‘What is surprising is the result is opposite to that of research on humans – people typically show greater neural activation for known words than novel words.’
The researchers say the dogs may show greater neural activation to a novel word because they sense their owners want them to understand what they are saying, and they are trying to do so.
Gregory said: ‘Dogs ultimately want to please their owners, and perhaps also receive praise or food.’
Half of the dogs in the experiment showed the increased activation for the novel words in their parietotemporal cortex.
This is an area believed to be similar to the angular gyrus in humans, where vocabulary is processed.
But the others showed heightened activity to novel words in other brain regions including parts of the left temporal cortex and amygdala, caudate nucleus and the thalamus.
Gregory said this could be linked to the range in breeds and sizes of the dogs, as well as possible variations in their abilities.
A major challenge in mapping dogs’ cognitive processes is the difference in the size of their brains.
The study does not mean spoken words are the most effective way for an owner to communicate with a dog.
In fact, other recent research by the same team showed the neural reward system of dogs is more attuned to visual and scent cues, than verbal ones.
Ashley added: ‘When people want to teach their dog a trick, they often use a verbal command because that is what we humans prefer.
‘From the dog’s perspective, however, a visual command might be more effective, helping the dog learn the trick faster.’
