From Scientific American:
Television can act like a painkiller when it comes to children and is more effective than a mother’s comforting, according to a small Italian study. The University of Siena study, published in Archives of Disease in Childhood, was based on 69 children aged seven to 12 who were divided into three groups to have blood taken. One group was given no distraction while the blood was being taken while mothers of children in the second group attempted to distract the youngsters by talking to them, soothing, and/or caressing them. In the third group, the children were allowed to watch television cartoons while the procedure was being carried out.