Brain Asymmetry -> Asymmetric Wagging

Asymmetric tail-wagging responses by dogs to different emotive stimuli (NY Times)

Fascinating article.

We all know about left brain and right brain. The left brain "specializes in behaviors involving what the scientists call approach and energy enrichment." The right brain "specializes in behaviors involving withdrawal and energy expenditure." Basically, this means that left brain is connected with positive feelings like love and safety and calm. The right brain goes with fleeing and depression.

We have also heard that the right brain controls the left side of the body, and the left brain controls the right side of the body. Apparently this manifests itself in humans in certain ways like muscles on the right side of your face showing happiness and left side showing sadness. Curious, the scientists, Giorgio Vallortigara, Angelo Quaranta, and Marcello Siniscalchi, thought. What about the dog's tail? It's smack in the middle of the body!

Well, turns out dog tails do indeed show emotional asymmetry. When dogs are happy, the wag more strongly to the right. (Higher amplitude) When they are frightened, they wag more to the left. Same thing happens for chimps scratching themselves.