We all know that dogs wag their tails to express happiness, but a new Italian study now suggests that dogs show pleasure by wagging their tails more towards the right, while negative feelings get a left-swaying wag.

An Italian neuroscientist at the University of Trieste, Dr. Giorgio Vallortigara, and two veterinarians from the University of Bari, Marcello Siniscalchi and Angelo Quaranta, closely watched 30 caged family pets of mixed breeds over 25 days, performing 10 tests per day.

The study, which was reported by the New York Times, states that dogs were shown four visual images through a slat in their cages: their owner, an unfamiliar human, a cat and an unfamiliar, dominant dog.

When the pet saw the most familiar image - its owner - it wagged its tail toward the right, while the picture of the dominant dog made it wag toward the left side.

The study, which appeared in the March edition of Current Biology, states that the left side of the brain in animals and humans, which controls the right side of the body, emotes feelings of love, safety and calm. The right side of the brain, which controls the left side of the body, tends to be associated with feelings of fear and depression.