"Diseases and disorders caused by dirty hands — like diarrhea — kill a child somewhere in the world about every 15 seconds,
and about half those deaths could be prevented with the regular use of soap, studies indicate.
But getting people into a soap habit, it turns out, is surprisingly hard...
We could talk about germs until we were blue in the face, and it didn’t change behaviors...
Habits are formed when the memory associates specific actions with specific places or moods...
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",
http://www.nytimes.com/2008/07/13/business/13habit.html?em