The term “peer” properly refers to a social equal (Hartup, 1983), but it is conventionally used by social scientists to refer to associates of the same age. In the course of daily living, individuals normally interact with persons from all stages of life, but it is among age-mates that the most intimate of human relationships – deep and abiding friendships and romantic relationships – are often formed.

Sociologists and developmental psychologists are virtually unanimous in agreeing that peer relations play a critical role during the transition from childhood to adulthood, when individuals must cast off their childhood identity and enter the larger world of adults:

Because peers take on heightened importance during the teenage years, and because criminal behavior peaks at these ages as well, it is natural to wonder whether the two phenomena are somehow linked. Before we can address that question, however, it is important to look more closely at the role of peers in human development.