At least into washing his or her hands [NYT]:
Dr. Hofmann and his co-author, Adam Grant, took baseline measurements of the amount of soap and disinfectant caregivers used in a large North Carolina hospital. Then they measured the change in soap use when they put up different signs by the dispensers. One sign read “Hand Hygiene Prevents You from Catching Diseases.” Another read “Hand Hygiene Prevents Patients from Catching Diseases.” And a third sign, which served as a control, had a generic message: "Gel In, Wash Out." The patient-focused sign produced a 33 percent increase in the amount of soap and disinfectant used per dispenser over a two-week period, compared with the other signs.