The social network effect Norms and feedback in adolescence

Peer influence has traditionally been associated with negative outcomes, particularly increased risk-taking behaviors. However, recent research highlights that adolescents also learn positive behaviors, such as prosocial actions, from their peers. Despite these advances, there remains limited understanding of the strategies individuals use to adapt to their social environments, and how exposure to social information shapes attitudes and behaviors across development. This dissertation builds on the perspective that social learning within real classroom peer groups can contribute to both socially undesirable and desirable outcomes, depending on whom adolescents learn from, how they learn, and the type of social information. It investigates multiple pathways through which social learning occurs during adolescence, focusing on their engagement with school-based social networks and social media. Specifically, it examines (a) the impact of social norms from various sources (e.g., peers, teachers) on adolescents’ norms and intention formation, and (b) the impact of social feedback (e.g., likes) on social media engagement. It proposes a framework grounded in norm-updating, intention-formation, and (reinforcement) learning models to explore these social learning dynamics during development. This framework integrates key elements that address literature gaps through a set of studies. In particular, the who question is addressed using two-waves experimental designs tailored to adolescents’ social networks, allowing to examine which social sources exert greater influence on adolescents’ personal norms and intentions for risk-taking and prosociality (chapters 2, 3). Using real classroom peer groups as information sources enhances ecological validity compared to previous experimental research that relied on relationships between unfamiliar or artificially generated peers. Furthermore, these experimental designs were also developed to address the how question by employing an integrative model to examine pathways of influence, focusing on change, and compare pathways across development (chapters 3, 4). Lastly, this dissertation investigates social learning within online contexts. It focuses on the impact of social information on adolescent social media behavior by employing social media trace data, computational modelling, and an experiment (chapter 5). These studies are embedded in a framework which mostly focuses on individuals' naturalistic environments and adheres to a no-deception approach.