Perhaps the biggest news story about youth crime this year has been “flash mobs”-- large gatherings of teens and young adults that can turn violent the way they did this summer in Philadelphia, triggering  earlier summer curfews. Then there are “flash robs” that overtake and shoplift en masse, especially from convenience stores. The massive “flash rob” at a Germantown, Md., 7-11 in August made national news, and similar eruptions this summer rocked the DC neighborhoods of Dupont Circle, Georgetown,and Minnesota Avenue  in Northeast DC.

Researchers often use the psychology of groups to explain what happens during flash mobs. When hordes of people (youths or otherwise) get together, “groupthink” takes over, and people do things they wouldn’t normally do. This is not a new idea, and decades of research on youth delinquency and gang involvement show that when delinquent youths get together, positive outcomes are rare, and youths who weren’t delinquent before often join crowds who are. Flash mobbing isn’t typical youth behavior, but young people between, say, 14 and 24 are involved in a disproportionate amount of all crime.

For youths especially, the influence of groups and group behavior can be powerful. One report on youth crime in DC suggests that “gangs and crews drive most of the youth participation in violence.” But we still don’t understand exactly how these group dynamics breed delinquency. How do interpersonal relationships and belonging to a “group”—be it a sports team, club, crew, or gang—affect an individual’s behavior?  What happens when youths belong to several groups? Are they more likely to commit crimes on their own, or to “co-offend” with peers?

These questions are ripe for social network analysis--examining an individual’s personal connections to tease out their influences on behavior. We’re doing that now with Temple University in two local communities. In a central DC neighborhood, known for gang and crew behavior, a local organization helped us canvass youths ages 14—21, who then took a lengthy survey on their behavior and closest contacts, be those adults or peers, family or friends.

Preliminary findings based on what these 160 or so kids told us helped us sketch a picture of group influence. Although about one third of youth said they saw a lot of gang or crew activity in their neighborhood, only 6 percent told us they were members themselves and 7 percent reported having sold drugs in the last six months. But we see much higher reports of delinquency or gang-involvement among people in the youths’ social networks. One out of five surveyed hung out with at least one gang member, and 15 percent with at least one person who sells drugs.  The same percentage reported committing crimes with at least one close friend.

So, yes, criminal behavior is contagious, but it doesn’t seem to go viral either. Instead of asking why youths and young adults commit crimes as part of groups, maybe we should look harder at what keeps kids from committing crimes when they hang out with delinquent or gang-involved friends. Indeed, one flash mobber caught on tape was going back to the counter to pay for her candy, apparently guided by second thoughts.

Note: The full title of this research, funded by the District of Columbia through the District of Columbia Crime Policy Institute, is Delinquent Behavior, Gang Involvement, and Social Networks of Youths in the District of Columbia. Check back for the full final report in early 2012.