The goal of this study was to examine behavioral norm effects in 2 peer contexts (classroom, school) on adolescent substance use (tobacco, alcohol, cannabis) and aggressive behaviors (bullying, physical fighting). Participants were 5,642 adolescents (M[subscript age] = 14.29 years, SD = 1.26; 49% boys). There were 3 hypotheses. First, behavioral…

Over the last decade, research on Internet addiction (IA) has increased. However, almost all studies in the area are cross-sectional and do not examine the context in which Internet use takes place. Therefore, a longitudinal study examined the role of conscientiousness (as a personality trait) and classroom hostility (as a contextual factor) in…