Turns out, the way a dog wags its tail works like Tinder. A wag to the right (like a swipe to the right) signals positive emotions — a green light, if you will. Researchers found more right wags when the dog interacted with people it was familiar with, like its owner. Conversely, more swishes to the left occurred when the dog interacted with strangers, signaling negative and uncomfortable emotions. "The direction of tail wagging does in fact matter," University of Trento researcher Giorgio Vallortigara explained, "and it matters in a way that matches hemispheric activation." To put it simply, when researchers tested their right versus left theory, they found that positive and negative sensations are indicated by the primary wag direction.
Barnard College psychologist Alexandra Horowitz explained that there is, however, more to tail wagging than the previous study indicates. In an email to the International Business Times, Horowitz said that real-time wags are much more subtle than they appear. Yes, the hemispheric comprehension carries some meaning, but it's not a full-fledged language. In fact, it might just serve as a mood indicator. Furthermore — "Dogs may have been predisposed to understanding humans this way based on cues they use to understand other dogs," Evan MacLean, the co-director of the Duke Canine Cognition Center explained. So, until more research is conducted, dog wags are like cute and cuddly mood rings that won't leave a copper stain on your finger. (Mood rings, of course, don't need to be fed, bathed, and curbed.) (International Business Times)