My main research interests are learning and memory processes: why we remember some things and not others, and how we can practice efficiently to remember the important bits.

I am interested in practice conditions that help learners remember information over time and that enable learners to apply their knowledge and skills in new situations.

Benefits of retrieval practice (testing effects)

Memory retrieval can be practiced: When learners recall information from memory it becomes easier to later recall that information again. This makes retrieval practice an effective learning strategy, for example, for vocabulary learning (e.g., Roediger & Butler, 2011; increased fluency: van den Broek et al., 2014).

My dissertation focused on the cognitive and neural underpinnings of retrieval practice and on boundary conditions that apply when retrieval practice is used in vocabulary exercises.

Desirable difficulties during learning

Retrieval practice is an example of a ''desirable difficulty'' (Bjork, 1994), a condition that makes practice more difficult or ''effortful'' but (thereby) leads to better longterm results.

Oher desirable difficulties besides retrieval that play a role in my research are spacing and interleaving: Repetitions that are spaced (or distributed) over time, lead to better learning than massed practice. Similarly, different items that are practiced in an intermixed order rather than blocked, are better remembered. I am particularly excited about computational approaches that make it possible to adjust spaced repetitions to learner performance, such as SlimStampen (Sense et al., 2016).

Vocabulary learning with mnemonics

Together with colleagues, I won the Memrise competition with a vocabulary learningvmethod that we developed. Several thousand online participants tested the five finalist methods, and ours led to the largest retention and highest enjoyment ratings. Our method featured a combination of keyword mnemonics (a visualization strategy to encode words) and adaptive spaced retrieval. See this article by the Psychonomic Society for more details. I'm now following up on this work together with students to test what the long-term effects are of encoding vocabulary with mnemonic tricks, for instance, on productive use.

The other team members were Marlieke van Kesteren, Anke Marit Albers, Ruud Berkers, Boris Konrad, Nils Müller, and Paul Konstantin Gerke.

Rest breaks during study

This is a fun project with Ludmila Nunes from Purdue University. We are looking at the effect of rest breaks from studying on learning results and metacognitive ratings. So far, we have been unable to replicate previous studies which showed benefits of exposure to nature (e.g., Berman et al., 2008).

New ideas in education

For several years, I have worked with case studies of learning environments for the OECD's Centre for Educational Research and Innovation (CERI). I loved analysing them - I got to read about many inspiring schools that found special ways to address the needs of their students and community; and learned about the stories of teachers and school leaders with good ideas, vision and determination.

I am always interested to hear more about new initiatives in education, and to learn about how they are refined and shared. This year, I have been involved in the design of the new teacher traineeships and wrote an article about the Euregioschule in Kranenburg, an interesting high school in which German and Dutch students receive bilingual education [download].


You can find copies of my publications (author version or full paper) here!


Berman, M. G., Jonides, J., & Kaplan, S. (2008). The cognitive benefits of interacting with nature. Psychological Science, 19(12), 1207–1212.

Bjork, R. A. (1994). Memory and metamemory considerations in the training of human beings. In J. Metcalfe & A. P. Shimamura (Eds.), Metacognition: Knowing about knowing (pp. 185–205). Cambridge, MA: MIT Press.

Roediger, H. L., & Butler, A. C. (2011). The critical role of retrieval practice in long-term retention. Trends in Cognitive Sciences, 15(1), 20–27.

Sense, F., Behrens, F., Meijer, R. R., & van Rijn, H. (2016). An individual’s rate of forgetting is stable over time but differs across materials. Topics in Cognitive Science, 8(1), 305–321.

van den Broek, G. S. E., Segers, E., Takashima, A., & Verhoeven, L. (2014). Do testing effects change over time? Insights from immediate and delayed retrieval speed. Memory, 22(7), 803–812.