Esther Mertens

| 93 Classmate Influence in Intervention The Role of Classmates’ Modeling and Reinforce- ment in a Universal School-Based Intervention Ad- dressing Positive Peer Relations The classroom is an important developmental context for students in which experiences with peers affect their academic, emotional, and social development (Rubin, Bukowski, & Parker, 2006). The classroompeer context is positive when students feel comfortable around their classmates, feel included in the group, experience few conflicts in the classroom, and experience no victimization by bullies (Boor-Klip, Segers, Hendrickx, & Cillessen, 2016). Not all students experience the classroom peer context as positive. For instance, in the Netherlands there are three educational tracks in the Dutch secondary school system of which more than half (54%; Central Bureau for Statistics, 2020) of the total student population follows the preparatory vocational education track. In this track, 20% of the students experience problems with their peers (Stevens & De Looze, 2018). Therefore, the aim of the present study was to examine the processes through which adolescents’ experienced peer context in the classroom is influenced by their classmates. Modeling and Reinforcement According to the social learning theory (Bandura, 1977), two major ways through which peer influences occur are modeling and reinforcement. Peers’ modeling and reinforcement can negatively and positively influence how students perceive the classroompeer context. Peers can model behavior that violates community or societal rules, i.e., deviant modeling, or positively evaluate such deviant behavior, i.e., deviant reinforcement (Piehler & Dishion, 2007). Both deviant modeling and reinforcement have consistently been linked to increases in adolescents’ deviant behavior such as aggression, antisocial behavior (e.g., Dishion & Tipsord, 2011), bullying (e.g., Doehne, Von Grundherr, & Schäfer, 2018), and victimization (e.g., Ando, Asakura, & Simons- Morton, 2005). In contrast, peers can model behavior according to prosocial values, principles, and actions with the intention to benefit others, i.e., prosocial modeling, or respond positively to such prosocial behavior, i.e., prosocial reinforcement (Piehler & Dishion, 2007; Memmott-Elison, Holmgren, Padilla-Walker, & Hawkins, 2020). Prosocial modeling and reinforcement have been linked to decreases in problem behaviors, 5