”If I like you, I wanna be like you!” The use of dynamic systems modeling in the understanding of friendship interactions and risk behaviors during adolescence

PhD ceremony: Ms. L. Ballato, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: ”If I like you, I wanna be like you!” The use of dynamic systems modeling in the understanding of friendship interactions and risk behaviors during adolescence

Promotor(s): prof. P.L.C. van Geert

Faculty: Behavioural and Social Sciences

The main aim of the present thesis is to build a theoretical and mathematical model of social interactions and risk behaviors during adolescence based on the perspective of complex dynamic systems. By using computer simulations, the model explicates the complex process of friendship formation and behavior transformation on different developmental time scales (e.g., here-and-now versus months and years). The central questions of the thesis are: How do friends promote changes in adolescents’ attitudes during short-term interactions and over time co-adopt their own behaviors towards the ones of their friends? To answer our questions we apply three levels of analysis: Theoretical, mathematical and empirical. In the first part of the thesis, we propose a dynamic systems theory of friendship interactions and risk behaviors during adolescence. In the second part, we translate the theoretical framework into mathematical equations and present the results of the model’s simulations, aimed at testing our hypotheses. In the last part of the thesis the results of the empirical study are presented. The empirical study has two aims: First investigating whether similarity changes over time and second to differentiate between influence and reinforcement.