In Flanders (Structuurdecreet, 2003) critical reflection is a general competency that students in professional higher education have to achieve to graduate. However, it seems for students in teacher education not obvious to reach a critical level in their reflections (Dinkelman, 2000; El-Dib, 2007). In four studies (with student teachers) it is investigated 1) to what extent participants reflect critically, and 2) if learner control has impact on critical reflection, this for two approaches to stimulate reflection: a non-linear and a linear structured one. The first study is an explorative study. In a field experiment (with a within subjects design) the impact of learner control on the degree of critical reflection is investigated. As an example of a linear structured approach to reflection a learning journal, according to the ALACT model is used; and as an example of a non-linear approach digital storytelling according to the guidelines of Lambert is used. Participants were third-year students. In the second study the results of the first study were checked in a more controlled setting, with first-year students. An online experiment with a pretest-posttest design was done. In the third and fourth study (with first-year students) the extent to which an approach to reflection is linearly structured, was varied within respectively digital storytelling and a learning journal. In the third study a pretest-posttest and in the fourth study a posttest-only design was used. Across all studies results reveal that reflections irrespective of the different conditions contained few elements of critical reflection. The results of the first study reveal a main effect of learner control and approach to reflection on the degree of critical reflection. Ample learner control and a linear structured approach to reflection lead to a higher score on the degree of critical reflection. The third study shows a main effect of learner control. With ample learner control the participants reflect more critically than with less learner control. The fourth study reveals a main effect of approach to reflection. When participants reflect with a linear structured learning journal, they obtain a higher score on the degree of critical reflection than with a non-linear structured learning journal.Based on the establishment that the reflections of the participants in this dissertation contain few elements of critical reflection, the question whether it is realistic to aim that pre-service teachers succeed to reflect critically (Dinkelman, 2000). Secondly (and especially) this low score on critical reflection reconfirms the relevance of the general research question of this dissertation: What are powerful elements of a learning environment that supports pre-service teachers to reflect critically? With this research on the impact of learner control (with a linear and non-linear approach to reflection) on critical reflection a framework for further research is presented.