Domestic dogs show many adaptations to living closely with humans, but they do not seem to reciprocate food-giving according to a study, publishing July 4 in the open-access journal PLOS ONE, led by Jim McGetrick and colleagues at the University of Veterinary Medicine in Vienna, Austria. The researchers trained 37 domestic dogs to operate a food dispenser by pressing a button, before separating the button and dispenser in separate enclosures. In the first stage, dogs were paired with two unfamiliar humans one at a time. One human partner was helpful—pressing their button to dispense food in the dog's enclosure—and one...