adolescence is a very group-oriented stage of the life course. The dominant form of social organization is the peer group, especially age-graded, same-sex peer groups. Thus, it is neither surprising that much criminological research has focused on the impact of peer group influences on delinquency nor surprising that this research has shown that group influences, in particular associating with delinquent peers, are among the strongest and most consistent predictors of delinquent behavior (Thornberry and Krohn, 1997). This observation is consistent with a fundamental proposition of social network theory – namely, that all social networks constrain the behavior of their members to be consistent with the dominant behavioral themes of the group (Krohn, 1986).

From this perspective the observation that gang members have higher rates of delinquency and violence than nonmembers may be somewhat spurious, simply reflecting the fact that gangs are one form of a delinquent peer group (Miller, 1982). If so, the “gang effect,” which has been frequently noted in the literature and in previous chapters, would really be a simple “peer effect” and gangs would merely be one type of delinquent peer group, albeit at the more extreme end of the continuum. If this view is correct, we should not expect differences in the level of involvement in delinquent behavior between adolescents who are members of street gangs and nonmembers who are involved in highly delinquent social networks.

Another school of thought, however, argues that street gangs are fundamentally different from nongang delinquent peer groups.