Giorgio Vallortigara of the Center for Mind/Brain Sciences of the University of Trento in Italy and colleagues are the first to show that dogs have asymmetrically organized brains like humans in an article published in the Oct. 31, 2013, issue of the journal Current Biology.
Vallortigara and colleagues had previously demonstrated that dogs wag their tails to the right when they feel positive emotions and wag their tails to the left when they feel negative emotions.
Activation of the left brain produces the wag to the right and activation of the right brain produces wagging to the left.
The researchers showed videos of other dogs wagging their tails to the right and to the left to test dogs. The test dog’s heart rate increased and they demonstrated more anxious behavior when the dogs saw tail wagging to the left. Tail wagging to the right produced a relaxed dog with lower heart rates.
Vallortigara suggests that the tail wagging behavior does not communicate emotional content to other dogs but is a function of the asymmetrically organized brains.
The research may be helpful to dog owners and veterinarians in interpreting the mood a dog has and what approach tail wagging behavior would dictate in handling the dog.