“…Particularly in childhood and adolescence, peers are a major source for support in emotional and practical domains as well as for the learning of fundamental interpersonal skills (Bierman, 2004;Pardini, Loeber, & Stouthamer-Loeber, 2005). However, just as peers are crucial for a healthy development, they also constitute some challenges and risks (Jung, Krahé, & Busching, 2017). Theories of aggression have long highlighted the relevance of peer relationships in the etiology of aggressive behavior and particularly emphasized the role of peers' normative beliefs about aggression (Moffitt, 1993;Patterson, DeBaryshe, & Ramsey, 1989).…”