“ Habits are formed when the memory associates specific actions with specific places or moods,” said Dr. Wood, a professor of psychology and neuroscience at Duke. “If you regularly eat chips while sitting on the couch, after a while, seeing the couch will automatically prompt you to reach for the Doritos. These associations are sometimes so strong that you have to replace the couch with a wooden chair for a diet to succeed.
http://www.nytimes.com/2008/07/13/business/13habit.html?pagewanted=1&ref=business
