Parents, kids, and teachers everywhere know the phrase: peer pressure. Prevention and education programs target peer pressure and give kids tools to say no or walk away when their friends offer drugs. Addiction recovery centers offer support for young adults and their families struggling with drug use. But despite these efforts, peer pressure can still play a powerful role in prompting kids to use drugs. When a teen’s friends smoke or use drugs, they are more likely to follow suit.   Part of the problem with adolescent drug use is that teens tend to overestimate how much and how often their peers are engaging in risky behaviors such as drug use. In one study, a group of popular students self-reported no marijuana use in the past month, but their peers estimated that they smoked between one and nine times during the last month, a significant departure from the actual occurrence. Of course, much of this disparity between perception and reality may be due to the posturing that occurs in adolescence: in order to appear cool, teens may exaggerate or fabricate stories about their drug use. But these perceptions, despite being false, can still bear weight in the halls of middle and high schools, pressuring kids to try drugs.   Why does peer pressure exert such a powerful influence on kids? Several different models have been proposed. Some researchers say that peer pressure is a factor of social learning, or observing…