By Julia Kamysz Lane
The next time your dog greets you when you come home, closely watch his tail. Scientists have discovered that a happy dog will wag harder to the right and an anxious dog will wag harder to the left.
The study’s findings, “Asymmetric tail-wagging responses by dogs to different emotive stimuli,” was recently published in Current Biology. Co-authors include neuroscientist Giorgio Vallortigara of the University of Trieste in Italy, and veterinarians Angelo Quaranta and Marcello Siniscalchi, at the University of Bari in Italy.
In humans, it’s well documented that the brain is divided into two cerebral hemispheres–left and right–which serve different functions and control opposite sides of the body. Most animals also demonstrate a difference between “left brain” and “right brain” functions. It is believed that the left brain in animals specializes in “approach and energy enrichment,” such as finding food. The right brain specializes in “withdrawal and energy expenditure,” such as fleeing in response to fear. Because the dog’s tail is located along the body’s midline, researchers questioned whether or not the tail displayed emotional asymmetry.
Thirty mixed-breed dogs, family pets, served as the researchers’ subjects. Each dog was put in a cage specially fitted with cameras to capture the precise angle of the dog’s tail movement. The dog was then shown four separate stimuli–his owner; a stranger; a friendly cat; and an unfamiliar, intimidating dog–for one minute each.
Next: the results