A naturally existing group of young boys (under 10 years) was followed over a period of several months in its natural setting, an Israeli slum. Additional data were gathered by interviews with family members, neighbors, and local criminals. It was found that the boys moved from conventional to delinquent behavior in a multi‐stage process. During the early stages, group processes undermined the prestige of paternal authority figures, leading to a state of an “authority vacuum” within the group. In the latter stages the boys associated with local older delinquents who filled this vacuum. This association resulted in a “quantum leap” in the delinquency of the boys, who learned delinquent behavior from their new authority figures.The creation of the authority vacuum seems to be a necessary condition for the boys’ association with the delinquents. It also enhanced their receptivity to the delinquents’ behavior patterns. Group processes seem to play a crucial role in the overall process.