Testing and spacing: Effective learning strategies for the classroom


Educational practices inspired and supported by cognitive science are increasing in popularity. This can be seen in the worldwide increase in both academic (e.g. Roediger and Karpicke, 2018) and practice-oriented publications (e.g. Surma et al., 2019). Apropos these developments, we highlight two robust learning strategies which draw on a rich tradition of research and practical applications, namely retrieval practice and spaced practice. Both promote long term learning across many domains and populations, are relatively easy to use, and can be readily adopted by most teachers without extensive training (Dunlosky et al., 2013). Such learning strategies often fall under the umbrella term desirable difficulties, a term coined by Robert and Elisabeth Bjork. They are desirable because they boost the objective of instruction (i.e., long-term learning, transfer) and are difficult because they pose challenges to the learner and slow down apparent learning in a way that the act of forgetting becomes the friend of future learning (e.g., Bjork et al., 2013). Their origin can be traced back to early research on human remembering and forgetting (Marsh and Butler, 2013).

Retrieval practice

Retention of knowledge and skills is enhanced when learners engage in retrieval practice (i.e., actively trying to remember what they’ve ‘learned’ by testing themselves or being tested by peers, parents, or teachers). Retrieval is a memory modifier making the retrieved material more accessible in the future due to the testing. Such retrieval has repeatedly been shown to be more beneficial than passive learning strategies such as re-reading. This is known as the testing effect. Teachers can exert substantial influence over students’ retrieval practice, influencing when and how much students practice inside and outside the classroom. While traditional forms of testing improve learning, this also goes for alternative forms of retrieval practice such as quizzes, end-of-chapter diagnostic questions, and whole-class response systems (e.g. clickers and erase boards). One might call this ‘no stakes’ testing. Teachers can model self-testing techniques to stimulate their students to consciously incorporate these techniques in their own study-repertoire. In that respect, Cornell-note taking and self-testing through flash cards both hold promise – when used properly – for better comprehension and memory in the long term.

Spaced practice

Shorter practice and study separated by a period of time typically improves retention compared to massed study in one long session. This is known as the spacing effect. An array of practical activities for implementing spaced practice in regular classroom practice are already present. Homework assignments targeting both old and new material, cumulative and/or weekly formative assessments, short review sessions, and implementation of a spiral curriculum all have an intrinsic spacing component under full teacher control. Also, merging retrieval and spacing creates optimal learning situations; retrieval practice followed by feedback is highly effective because this feedback serves as a spaced exposure. Students can apply spaced practice by designing a study schedule where they space their study sessions over time in a thoughtful way instead of cramming the night before an exam. 

Obvious or not?

While implementing retrieval practice and distributed practice might seem obvious, teachers should be aware that learners are not innately aware of the non-intuitive benefits of desirable difficulties. Also, textbook authors often err by massing practice on one topic in one single chapter instead of periodically returning to earlier materials to encourage spaced retrieval practice. Even when students engage in self-testing as a study strategy, they do so primarily to assess what they already know, often not understanding that the testing itself enhances learning. This makes it all the more important that teachers be aware that these learning strategies not only strengthen their classroom practice but are also capable of informing and supporting their students on their pathway to become better self-regulated learners. 



Bjork RA, Dunlosky J and Kornell N (2013) Self-regulated learning: beliefs, techniques, and illusions. Annual review of psychology 64: 417–444.

Dunlosky J, Rawson KA, Marsh EJ, et al. (2013) Improving students’ learning with effective learning techniques: Promising directions from cognitive and educational psychology. Psychological Science in the Public Interest. 14(1): 4–58.

Marsh EJ, Butler AC (2013) Memory in educational settings. In: The Oxford Handbook of Cognitive Psychology. New York: Oxford University Press, pp. 299–317.

Roediger HL and Karpicke JD (2018) Reflections on the Resurgence of Interest in the Testing Effect. Perspectives on Psychological Science. 13(2): 236–241.

Surma T, Vanhoyweghen K, Sluijsmans D, et al. (2020) Lessons for Learning: Twelve Building Blocks for Effective Teaching. Woodbridge: John Catt


Share your experiences with educators globally by joining the discussion below. How do these approaches enhance students’ learning or how might they?

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