In the 1970s, Canadian psychologist Bruce K. Alexander was doing research on mice, trying to better understand the nature of addiction. He conducted several studies in which one rat was positioned in a small age. Within the cage were to water bottles, one with regular water and one with water laced with either heroin or cocaine. Nearly 100 percent of the time, the rat became obsessed with the drugged water and drank until it died.

Dr. Alexander spent lots of time contemplating why this was happening. In 1978, he conducted a follow-up experiment that has since revolutionized the way drug addiction as understood.

He build a large colony of house rats, with more than 200 times the floor space of a standard lab rat cage. This “rat park” experiment culminated in the leading breakthrough of the time: the underlying connection between a person’s environment and addiction.

Within rat park, there were plenty of incredible things for a rat to do. There was lots of cheese, toys to play with, open space to run through, tubes to exposes, and, most importantly, lots of other rats to hang out with.

Also included in rat park were the two water bottles as used in previous experiments, one with regular water and the other with drug laces water. Interestingly, in rat park, the rats hardly ever used the drug water, preferring the regular water instead. None of the rats ever used the drug water impulsively, and none of them ever overdosed, as other rats did in the small and secluded cages.

This research on rats has been related to two similar instances among humans. First the pervasive drug addictions that occurred among American troops during the Vietnam war.

While overseas, nearly 20 percent of the 2.7 million soldiers developed an addiction to heroin. In response to this situation, President Richard Nixon dedicated to fighting the evil of drugs. After laying out a program of prevention and rehabilitation, Nixon requested research be done on the addicted servicemen once they returned home.

The researcher charged with the job was a well-respected psychiatric researcher named Dr. Lee Robins, who was given extensive access to enlisted men in the army so that she could get the job done. First, she tested all the soldiers in Vietnam. Sure enough, nearly 20 percent of all the soldiers self-identified as addicts.

Those who were addicted were required to stay in Vietnam until the heroin was out of their system. They were then monitored when they returned home to their lives in the United State. Yet, to Robin’s surprise, only 5 percent of the previously addicted soldiers relapsed when they came home.

Everyone thought that somehow Dr. Lee was lying, or she did something wrong, or she was politically influenced. She spent months, if not years, trying to defend the integrity of the study. Being addicted in Vietnam didn’t mean you were an addict in America.

Even though people couldn’t fathom the soldiers behavior, forty-five years later, Dr. Lees findings are now widely accepted. Much of your behavior is unconsciously cued by your environment.

Even behaviors you detest and don’t want to engage in.

For example, Dr. David Neal, a Duke University psychologist, said: “For smokers the view of the entrance to their office building-which is a lace that they go to smoke all the time-became a powerful mental cue to go and perform that behavior.” The more repeated the cycle, the more ingrained the cue becomes, making it extremely difficult to resist. By changing the default of there the smoker parks their car and enters the building, they could eliminate the trigger.

Dr. Wendy Wood explains an important reason why triggers in our environment can be so powerful: “We don’t feel sort of pushed by the environment,” she says. “but, in fact, we’re very integrated with it.”

So the best way to alter addiction or any form of undesired behavior is to disrupt your environment. Even by making small changes, such as eating your impulsive midnight snack with your non-dominant hand, can alter the action sequence and learned body response that is driving your behavior. This pulls your conscious mind back into the moment, allowing your prefrontal cortex the time to consider of you really want to make the decision you are about to make. It’s a brief sort of window of opportunity to think, “Is this really what I want to do?”

Hence, the primary theory behind why the Vietnam soldiers relapse rate was so low was because, after being treated for their physical addiction in Vietnam, they returned to a place radically different from the environment where their addiction existed. Addictions, like behaviors, are environmental.

Smokers, for example, can go hours without even thinking about smoking when they’re engaged in certain activities or in certain situations. Most smokers admit to not experiencing smocking craving while on an airplane. Within that context, smocking simply isn’t  an option. The craving doesn’t persist, and the mind focuses on something else.