I am who I am with: The link between different types of social interaction partners and personality in adolescence

Dynamic personality models highlight the importance of malleable personality states and social interactions for personality trait development. Integrating both ideas, this research examined how interactions with family members, friends, teachers, and others relate to, first, personality state expression, and, second, personality trait development in adolescence. In two separate German samples ( N overall = 445, M age = 16.8; 80.9 % female), we combined data on personality states during daily social interactions (4268 reports) with self-reported personality traits measured over 6–12 months. Focusing on personality states, multilevel models indicated greater within-person variability compared to between-person differences. Conditional models revealed that adolescents experienced higher state extraversion, openness to new experiences, agreeableness, and conscientiousness during interactions with friends compared to interactions with family. In interactions with teachers and others, they reported higher state neuroticism, openness to new experiences, and conscientiousness. Considering adolescents’ personality traits over time, latent growth models showed that neuroticism declined on average. Apart from that, most traits showed high rank-order stabilities, no mean-level change, no substantial variance in change, and there was little evidence for bottom-up effects of social interaction frequency on personality changes. We conclude with a discussion of future directions in studying the role of social interactions in personality trait development.