Longitudinal Associations Between Delinquent Behaviour of Friends and Delinquent Behaviour of Adolescents: Moderation by Adolescent Personality Traits

In this longitudinal study, we examined whether personality traits (parent‐rated Big Five personality traits) render some adolescents more susceptible than others to delinquent behaviour of friends, predicting rank‐order changes in adolescents' self‐reported delinquent behaviour. We examine susceptibility to both perceived (reported by adolescents) and self‐reported (reported by friends) delinquent behaviour of friends. Participants in this two‐wave study were 285 Dutch adolescents and their best friends. The adolescents (50% girls) were 15.5 years old on average (SD = 0.8 years), and their best friends (N = 176; 58% girls) were 15.1 years old (SD = 1.5 years). Perceived (but not self‐reported) delinquency of friends predicted a stronger increase in adolescent delinquency 1 year later, especially among adolescents low or average on conscientiousness. Emotional stability, agreeableness, extraversion and openness did not moderate associations between delinquency of friends and delinquency of adolescents. Our findings show that low conscientiousness serves as a risk factor, increasing vulnerability to perceived delinquent behaviour of friends, while high conscientiousness serves as a protective factor, increasing resilience to perceived delinquent behaviour of friends. Our findings also show that adolescents are susceptible to, and differ in susceptibility to, friends' delinquent behaviour as they perceive it—not to delinquent behaviour as reported by friends themselves. Copyright © 2015 European Association of Personality Psychology