You might think a wagging tail is a wagging tail, but for dogs there is more to it than that. Dogs recognize and respond differently when their fellow canines wag to the right than they do when they wag to the left. The findings reported in the Cell Press journal Current Biology on Oct. 31, 2013 show that dogs, like humans, have asymmetrically organized brains, with the left and right sides playing different roles. Check out the study's video, "Visual Naturalistic Stimuli."
In video from the researchers, the dogs' visual stimuli (naturalistic and silhouette) exhibits prevalent left- or right-asymmetric tail wagging. Stationary stimuli such as the dogs not wagging their tail are also showed in the video.
Scientists have shed more light on how the movements of a dog's tail are linked to its mood, according to the October 31 BBC News article by Rebecca Morelle Science reporter, BBC World Service, "Scientists decipher dog-tail wags." Or check out the study's abstract in the October 31, 2013 issue of Current Biology, "Seeing Left- or Right-Asymmetric Tail Wagging Produces Different Emotional Responses in Dogs."
Researchers say that canines can spot and respond to subtle tail differences such as happy dogs wagging tails to the right (from the dog's position). Nervous or fearful dogs wag their tails to the left, according to previous research. Also, dogs respond to "lop-sided" tail wags from other dogs
Left-right asymmetries in behavior associated with asymmetries in the brain are widespread in the animal kingdom, and the hypothesis has been put forward that they may be linked to animals’ social behavior. Dogs show asymmetric tail-wagging responses to different emotive stimuli —the outcome of different activation of left and right brain structures controlling tail movements to the right and left side of the body.
A crucial question, however, is whether or not dogs detect this asymmetry. In the new study, scientists report that dogs looking at moving video images of conspecifics exhibiting prevalent left- or right-asymmetric tail wagging showed higher cardiac activity and higher scores of anxious behavior when observing left- rather than right-biased tail wagging.
The finding that dogs are sensitive to the asymmetric tail expressions of other dogs supports the hypothesis of a link between brain asymmetry and social behavior and may prove useful to canine animal welfare theory and practice.
Dogs know a left from a right tail wag
According to an October 31, 2013 news release, "Dogs know a left-sided wag from a right," you might think a wagging tail is a wagging tail, but for dogs there is more to it than that. Dogs recognize and respond differently when their fellow canines wag to the right than they do when they wag to the left. The findings show that dogs, like humans, have asymmetrically organized brains, with the left and right sides playing different roles.
The discovery follows earlier work by the same Italian research team, which found that dogs wag to the right when they feel positive emotions (upon seeing their owners, for instance) and to the left when they feel negative emotions (upon seeing an unfriendly dog, for example). That biased tail-wagging behavior reflects what is happening in the dogs' brains. Left-brain activation produces a wag to the right, and right-brain activation produces a wag to the left.
But does that tail-wagging difference mean something to other dogs? Yes it does, the new study shows
While monitoring their reactions, the researchers showed dogs videos of other dogs with either left- or right-asymmetric tail wagging. When dogs saw another dog wagging to the left, their heart rates picked up and they began to look anxious. When dogs saw another dog wagging to the right, they stayed perfectly relaxed. The direction of tail wagging does in fact matter, and it matters in a way that matches hemispheric activation," says Giorgio Vallortigara of the Center for Mind/Brain Sciences of the University of Trento, according to the news release.
"In other words, a dog looking to a dog wagging with a bias to the right side—and thus showing left-hemisphere activation as if it was experiencing some sort of positive/approach response—would also produce relaxed responses. In contrast, a dog looking to a dog wagging with a bias to the left—and thus showing right-hemisphere activation as if it was experiencing some sort of negative/withdrawal response—would also produce anxious and targeting responses as well as increased cardiac frequency. That is amazing, I think."
Vallortigara doesn't think that the dogs are necessarily intending to communicate those emotions to other dogs. Rather, he says, the bias in tail wagging is likely the automatic byproduct of differential activation of the left versus the right side of the brain. But that's not to say that the bias in wagging and its response might not find practical uses; veterinarians and dog owners might do well to take note.
"It could be that left/right directions of approach could be effectively used by vets during visits of the animals or that dummies could be used to exploit asymmetries of emotional responses," Vallortigara says in the news release. You may wish to check out the study in Current Biology, by Siniscalchi et al.: "Seeing left or right asymmetric tail wagging produces different emotional responses in dogs."
Dog's mood offers insight into owner's health
You may also check out the study, on how a dog's mood lets people know more about the dog handler's health, according to the October 7, 2013 news release, "Dog's mood offers insight into owner's health." Monitoring a dog's behavior could be used as an early warning sign that an older owner is struggling to cope or their health is deteriorating.
Experts at Newcastle University, UK, are using movement sensors to track normal dog behavior while the animals are both home alone and out-and-about. Providing a unique insight into the secret life of man's best friend, the sensors show not only when the dog is on the move, but also how much he is barking, sitting, digging and other key canine behaviors.
By mapping the normal behavior of a healthy, happy dog, Dr Cas Ladha, PhD student Nils Hammerla and undergraduate Emma Hughes were able to set a benchmark against which the animals could be remotely monitored
This allowed for any changes in behavior which might be an indication of illness or boredom to be quickly spotted. Presenting their findings at the 2013 UbiComp conference in Zurich, project lead Ladha, says the next step is to use the dog's health and behavior as an early warning system that an elderly owner may be struggling to cope.
"A lot of our research is focused on developing intelligent systems that can help older people to live independently for longer," explains Ladha, in the news release. Ladha is based in Newcastle University's Culture Lab. "But developing a system that reassures family and carers that an older relative is well without intruding on that individual's privacy is difficult. This is just the first step but the idea behind this research is that it would allow us to discretely support people without the need for cameras."
Behavior imaging expert Nils Hammerla adds, according to the news release, "Humans and dogs have lived together in close proximity for thousands of years, which has led to strong emotional and social mutual bonds. A dog's physical and emotional dependence on their owner means that their wellbeing is likely reflect that of their owner and any changes such as the dog being walked less often, perhaps not being fed regularly, or simply demonstrating 'unhappy' behavior could be an early indicator for families that an older relative needs help."
How the technology works
In the UK, around 30% of households own at least one pet dog, totaling an estimated 10.5 million animals. Designed to provide an indicator of animal welfare in an age when dogs are increasingly left alone for long periods of time, the team created a hi-tech, waterproof dog collar complete with accelerometer and collected data for a wide range of dog breeds.
"In order to set the benchmark we needed to determine which movements correlated to particular behaviors, so in the initial studies, as well as the collars, we also set up cameras to record their behavior," explains Ladha in the news release
Analyzing the two datasets, the Newcastle team were able to classify 17 distinct dog activities such as barking, chewing, drinking, laying, shivering and sniffing. The team also assessed the system against different breeds
"This had to work for all dogs," explains Ladha in the news release, "so the challenge was to map distinct behaviors that correlated whether the collar was being worn by a square-shouldered bulldog or a tiny chiwawa."
Hammerla adds in the news release, "This is the first system of its kind which allows us to remotely monitor a dog's behavior in its natural setting. But beyond this it also presents us with a real opportunity to use man's best friend as a discreet health barometer. It's already well known that pets are good for our health and this new technology means dogs are supporting their older owners to live independently in even more ways than they already do."