" in an early study nursery-school-age children chosen because they were terrified of dogs merely watched a little boy playing happily with a dog for twenty minutes a day. This exhibition produced such marked changes in the reactions of the fearful children that after only four days, 67 percent of them were willing to climb into a playpen with a dog and remain confined there, petting and scratching it while everyone else left the room. Moreover, when the researchers tested the children’s fear levels again one month later, they found that the improvement had not evaporated during that time; in fact, the children were more willing than ever to interact with dogs. "

― Robert B. Cialdini , Influence: The Psychology of Persuasion