What makes dogs so friendly? A study from Monique Udell, an animal behaviorist at Oregon State University in Corvallis, and Princeton University geneticist Bridgett vonHoldt has found a genetic link between friendly dogs and super-outgoing people. The study, which appears in Science Advances, found variations in several genes that make dogs more affable than wolves and some dogs friendlier than others. This study seems to provide support for the "survival of the friendliest" hypothesis of dog domestication. Learn more here.