A study from the Universities of Pisa and Perugia, Italy, found that dogs are happier when given affectionate petting before being left alone. The study involved 10 healthy dogs without attachment issues, and tests were conducted in an outdoor, fenced-in area. In one test, the owner petted the dog during a one-minute chat with a researcher before leaving; in another test, the owner ignored the dog during the chat. After separation, the dogs' cortisol levels were tested and found to be the same in both tests, but heart rates went down in the "with gentle touch" test, indicating dogs were more relaxed.
