For years, Dr. Val Curtis has been persuading people in the developing world to wash their hands habitually with soap. Meanwhile, researchers at Duke and Cornell universities were examining how often smokers quit while vacationing and how much people eat when their plates are deceptively large or small. Those and other studies revealed that as much as 45 percent of what we do every day is habitual- that is, performed almost without thinking in the same location or at the same time each day, usually because of subtle cues. Today, public health campaigns are being revamped to employ habit-formation characteristics, according to people involved in those efforts.
