A staggering 20% of American servicemen serving in Vietnam in the 1970s admitted to heroin addiction.

Before being allowed to return stateside every soldier was tested for heroin and any that tested positive were forced to detox while overseas. Follow-up studies of these returning soldiers showed that only about 5% relapsed back to heroin use during the first year once back in America. By contrast, at that time, about 90% heroin addicts treated within America would relapse back to heroin use during the first year after treatment.

What was going on to explain such a dramatic difference in relapse rates?

According to USC psychologist Wendy Wood, environmental change explains the difference and the lessons of the returning Vietnam solider are applicable to anyone who's trying to change a bad habit. According to Wood, addiction treatment in the 1970s and 1980s focused largely on having people make changes to internal systems of goals and intentions. What the Vietnam vets got when they returned home after treatment however was a massive change to their everyday environment - and it was this complete transformation of daily life and routine that made it so much easier for the returning heroin addicts to remain abstinent.

For example, a smoker who always lights up when talking on the phone and while having a morning coffee might find it easier to quit if he/she travels to some environment that has neither phones nor coffee! The act of having that morning coffee or talking on the phone causes the mind to go on autopilot and to seek to repeat a behavior that, through so much repetition, has become ingrained in the complex sequence of that activity.

Wood explains that although we don't often think of our physical environment influencing our behaviors that it does play a stronger role in our decision-making than we realize and that we actually become quite integrated with the environment in which we live - and because of this, she argues, we can increase our ability to overcome bad habits by making small changes to our habitual routines. Small changes to our everyday environment, she explains, keep the brain from going into learned autopilot mode and help you keep the conscious brain much more involved in your decision making process.