Deci et al. (1991) pointed out that choice has a positive effect on interest and engagement because people have an innate psychological need for competence, belonging, and autonomy. In self-determination research, having a choice is a means to satisfy that need for autonomy. In the PBL classroom students have the choice to determine what they wish to study (i.e. select their own learning goals and conduct their individual self-study), which, according to self-determination theory, should lead to a feeling of autonomy. Feeling autonomous and empowered in the classroom is expected to have a motivating effect encouraging students to engage themselves cognitively with the task at hand.