People in recovery have known this for a long time...
http://goo.gl/EoVmTyUnique person-specific cues--such as the presence of a specific friend or hearing a specific song--appear to have a robust effect on craving addictive substances, a recent study shows. The study also found that person-specific cues may have a longer effect on craving than more general substance-specific cues, such as the presence of bottles, syringes, or lighters.
The study included 132 outpatients beginning treatment for alcohol, tobacco, cannabis, or opiate addiction. Using mobile technologies, participants were questioned 4 times per day relative to craving, substance use, and exposure to either substance-specific cues or personal cues unique to that individual.