• crocodile attacks,
• amusement park accidents,
• chemical warfare terrorism,
• the 2005 London bombings,
• workplace violence, and
• youth gun violence.
For purposes of illustration, I have prepared two preliminary Haddon matrixes addressing the largely overlapping phenomena of violent youth gangs and violent political extremists (Tables II-3 and II-4). There appear to be important shared characteristics of these superficially different social problems. Both involve in-groups of persons who share an identity that is in conflict with one or more out-groups. Another similarity is that individuals who elect to participate are, in essence, electing a live-fast-die-young life history strategy (Victoroff et al., 2011). Another may be that both gang members and extremists are preoccupied with collective blame of others. It seems plausible that both urban youth and extremists may be propelled, to some degree, by audiovisual media depictions or incitement of violence (Tsfati, 2002; Atran and Stern, 2005; Gunter, 2008; Wright, 2008; Anderson et al., 2010). Moreover, it was recently reported that, just as elevated testosterone (T) levels are associated with antisocial behavior among adolescent boys, evidence suggests that elevated T may be associated with support for extremist violence among adolescent boys (Victoroff et al., 2011).
While it is tempting to propose a distinction—that youth gangs are not ideologically driven while extremist groups are—this overstates the difference. Although urban youth gangs may not base their violent plans on a coherent, articulated religious or political ideology, they clearly base their behaviors, in part, on a shared weltanschauung in which the local world is viewed as a hostile, hopeless, and insecure place in which conventional values are irrelevant, injustice is rampant, social Darwinism determines success, and in-group age-related gang affiliation offers identity, fictive kinship, and physical protection. Thus, gangsters evading the police in a crack house in Detroit or extremists evading drones in the souks of North Waziristan perhaps share the worldview of a beleaguered oppositional counterculture.
This is not by any means to say that urban youth gangs and violent extremist groups are identically structured or motivated. In conversations with members of Los Angeles gangs and with members of Hamas, both similarities and differences emerge. One important difference between these types of groups is that gang violence is often reactive—an immediate response to a confrontation with a rival, often unplanned, while terrorist