Marijn was appointed assistant professor at the department of Interdisciplinary Social Science at Utrecht University in 2016. She is a behavior scientist, focusing on understanding human behavior and designing and understanding social policy for behavior change. Her research focuses on sustainability behavior, health behavior, and public health. In her work, Marijn uses insights from social psychology, health psychology, health science, consumer science and communication science. Specific research interests include social influence processes, social norms, social identity, socio-economic inequities, autonomy, motivation, reactance, persuasive communication, self-regulation, and nudging. In addition to her research, Marijn coordinates the Social Policy and Public Health master's program, and and contributes to teaching and coordination of courses on both the bachelor and master levels. She also supervises students' internships and theses.

Marijn obtained her PhD in health psychology in 2014. Her dissertation on the influence of social norms on young people’s eating behavior received the 2015 Herman Schaalma award from the European Health Psychology Society. During her years as a PhD candidate, Marijn helped manage the EU-funded TEMPEST project (see here). Upon receiving her PhD, Marijn moved to the University of Konstanz as a postdoctoral researcher. She was responsible for the management and coordination of 80 partners within one work package of DEDIPAC, a large-scale interdisciplinary and international research project and knowledge hub (see here). One main output of this work package is an interactive, dynamic framework of the determinants of diet framework (DONE framework; see here). Marijn simultaneously continued her experimental research on social influence, reactance, and health behavior, also supervising a PhD project on this topic.