I’ve got to admit I’ve never paid much attention to which way Ace’s tail is wagging — mostly to the right, or mostly to the left.
More often, it just seems to go back and forth, one side to the other, which is kind of the definition of wag.
But researchers in Italy, who first reported that the prominent direction of the wag signifies whether a dog is experiencing positive or negative feelings, now say other dogs are aware of this subtle distinction, and apparently have been for some time, indicating they — dogs — are much more on top of things than researchers.
Researchers at the University of Trento, in a new study, had dogs watch videos of other dogs wagging their tails. They found, according to a study reported in the journal Current Biology, that dogs watching another dog whose tail is wagging left showed signs of anxiety, including a higher heart rate. When watching a tail wag right, they remained calm.
When watching “Two Broke Girls” the dogs asked if they might please leave the room. (Not really.)
Returning to seriousness, the Italian researchers first reported in 2007 that dogs convey a wide array of emotions through the tail wag — not just happiness. A wag to the left indicates negative emotions; a wag to the right indicates positive ones. The directions are as seen when standing behind a dog.
In the earlier study, 30 dogs were placed, one at a time, in a large box surrounded with black plastic to prevent any visual stimulus (except maybe to dogs who find black plastic stimulating). The dogs were then shown a stimulus for 60 seconds — a dominant Belgian Malinois, a cat in a cage, their owners, and a strange human, by which we only mean one they hadn’t met.
A system for measuring the tail movements of each dog was established — far too complex to go into here. Suffice to say, as the scientists put it:
“Tail wagging scores associated with the different stimuli were analyzed from video-recordings. Positions of the tail were scored every 10 seconds by superimposition on the computer screen of a cursor on the long axis of the body: the maximum extents of the particular tail wag occurring at each 10 second interval was recorded. Using single frames from video recording two angles were identified with respect to the maximum excursion of the tail to the right and to the left side of the dog’s body. Tail wagging angles were obtained with reference to the axes formed by the midline of the dog’s pelvis – the segment extending lengthwise through the dog’s hips, drawn from the largest points as seen from above and the axes perpendicular to it.”
When faced with their owner, dogs exhibited a “striking right-sided bias in the amplitudes of tail wagging.” Less robust right-sided wags were observed also when the dogs were shown unfamiliar humans. When faced with a cat, dogs showed very reduced tail wagging, but still a slight bias favoring the right side. Seeing a dominant unfamiliar dog led the dogs in the study to wag more to the left.
The first study reported: “How far asymmetric tail-wagging responses are associated with postural asymmetry in preparation to the stimuli is difficult to say.” (You can say that again) “It is likely that control of the flexure of the vertebral column is the same for the tail as well as the rest of the column, but the method we used for scoring tail-wagging responses and the panels flanking the body of the animal in the test-cage minimized any effect of asymmetric posture associated with spine bending.”
I’ve got to wonder which way the dogs’ tails wagged — or if they tucked them between their legs — when they were listening to the scientists talk.
The researchers stop short of saying wagging tails are a mode of communication between dogs.
“This is something that could be explained in quite a mechanistic way,” said Giorgio Vallortigara, a neuroscientist and an author of both studies. “It’s simply a byproduct of the asymmetry of the brain.” Dogs, he explains, have asymmetrically organized brains, like humans (or at least most of them): ”The emotions are associated presumably with activation of either the right or left side of brain,” he said. “Left-brain activation produces a wag to the right, and vice versa.”
But it would seem to me that if one dog is moving his tail, and another is drawing conclusions from that motion, as the scientists say is the case, that’s communication — perhaps even a clearer form thereof than that to which the scientists are prone.
(Photo: Department of Veterinary Medicine, University of Bari)
Posted by John Woestendiek November 3rd, 2013 under Muttsblog.
Tags: aggression, animal, anxiety, behaviors, calm, communication, dog, dogs, emotions, excited, excitement, experiment, feelings, heart rate, indicators, italy, language, left brain, negative, pets, positive, research, right brain, scientists, signs, tail, tails, university of trento, wag, wagging, wags