While many dogs owners think their pets really do understand them, a new study has found they really do have a 'rudimentary' understands of words.

It could help explain the 'squirrel phenomenon' where dogs instantly perk up, become agigated and even start hunting for squirrels when their owner tells them one is close by.

However, researchers have been unclear what is actually happening in the canine brain - and how much they really understand.

Scroll down for video

Eddie, a golden retriever-Labrador mix, was part of the study, along with his toys Piggy and Monkey. For the study, 12 dogs of varying breeds were trained for months by their owners to retrieve two different objects, based on the objects' names.

'Many dog owners think that their dogs know what some words mean, but there really isn't much scientific evidence to support that,' says Ashley Prichard, a PhD candidate in at Emory's University and first author of the study.

'We wanted to get data from the dogs themselves - not just owner reports.'

The study, published in Frontiers in Neuroscience, used brain imaging to probe how dogs process words they have been taught to associate with objects.

The results suggest that dogs have at least a rudimentary neural representation of meaning for words they have been taught, differentiating words they have heard before from those they have not.

'We know that dogs have the capacity to process at least some aspects of human language since they can learn to follow verbal commands,' adds Emory neuroscientist Gregory Berns, senior author of the study.

'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.'

HOW THE STUDY WAS DONE Study participant Stella and her toys For the current study, 12 dogs of varying breeds were trained for months by their owners to retrieve two different objects, based on the objects' names. Each dog's pair of objects consisted of one with a soft texture, such as a stuffed animal, and another of a different texture, such as rubber, to facilitate discrimination. Training consisted of instructing the dogs to fetch one of the objects and then rewarding them with food or praise. Training was considered complete when a dog showed that it could discriminate between the two objects by consistently fetching the one requested by the owner when presented with both of the objects. During one experiment, the trained dog lay in the fMRI scanner while the dog's owner stood directly in front of the dog at the opening of the machine and said the names of the dog's toys at set intervals, then showed the dog the corresponding toys. Eddie, a golden retriever-Labrador mix, for instance, heard his owner say the words 'Piggy' or 'Monkey,' then his owner held up the matching toy. As a control, the owner then spoke gibberish words, such as 'bobbu' and 'bodmick,' then held up novel objects like a hat or a doll. Advertisement

The Emory researchers focused on questions surrounding the brain mechanisms dogs use to differentiate between words, or even what constitutes a word to a dog.

The results showed greater activation in auditory regions of the brain to the novel pseudowords relative to the trained words.

'We expected to see that dogs neurally discriminate between words that they know and words that they don't,' Prichard says.

'What's surprising is that 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.

'Dogs ultimately want to please their owners, and perhaps also receive praise or food,' Berns says.

Half of the dogs in the experiment showed the increased activation for the novel words in their parietotemporal cortex, an area of the brain that the researchers believe may be analogous to the angular gyrus in humans, where lexical differences are processed.

The other half of the dogs, however, showed heightened activity to novel words in other brain regions, including the other parts of the left temporal cortex and amygdala, caudate nucleus, and the thalamus.

A major challenge in mapping the cognitive processes of the canine brain, the researchers acknowledge, is the variety of shapes and sizes of dogs' brains across breeds.

HOW MUCH DO DOGS UNDERSTAND? A previous study to investigate how dog brains process speech has revealed canines care about both what we say and how we say it. It discovered that dogs, like people, use the left hemisphere to process words, and the right hemisphere brain region to process intonation. Trained dogs around the fMRI scanner used in the study: Dogs, like people, use the left hemisphere to process words, and the right hemisphere brain region to process intonation, according to the new study in Science. It found praise activates dog's reward centre only when both words and intonation match, according to the new study in Science. Researchers also say dogs developed the neural mechanisms to process words much earlier than thought. 'The human brain not only separately analyzes what we say and how we say it, but also integrates the two types of information, to arrive at a unified meaning. 'Our findings suggest that dogs can also do all that, and they use very similar brain mechanisms,' said lead researcher Attila Andics of Department of Ethology and MTA-ELTE Comparative Ethology Research Group at Eötvös Loránd University in Budapest. Advertisement

'Dogs may have varying capacity and motivation for learning and understanding human words,' Berns says, 'but they appear to have a neural representation for the meaning of words they have been taught, beyond just a low-level Pavlovian response.'

This conclusion does not mean that spoken words are the most effective way for an owner to communicate with a dog.

In fact, other research also led by Prichard and Berns and recently published in Scientific Reports, showed that the neural reward system of dogs is more attuned to visual and to scent cues than to verbal ones.

'When people want to teach their dog a trick, they often use a verbal command because that's what we humans prefer,' Prichard says. 'From the dog's perspective, however, a visual command might be more effective, helping the dog learn the trick faster.'