“Interleaving topics or tasks allow learners to form links or connections to previously taught information, thereby facilitating the retention and deeper understanding of new material,” according a 2019 study titled “The Clinical Teacher’s Toolbox” by McSparron, et al. Furthermore, studies suggest that interleaving may be particularly beneficial for adult learners, when longer study is required, and among learners who are experts or have mastered some aspects, as their working memory is stronger and can build on prior knowledge or skills quicker.
The concept of distributive practice or spacing of information has repeatedly been shown to improve memory retention as early as 1885 with Hermann Ebbinghuas’ studies on “the forgetting curve.” The ability to revisit information in spaced intervals — and longer intervals between spacing — assists with long-term memory retention and can prevent decay of critical information, commonly known as forgetting.
The goal is not to relearn or re-present an entire lecture or skill, but to trigger salient points or skills practice for reinforcement. The testing effect is also a useful tool as part of spaced learning, whether learners test themselves or clinical educators provide the testing. Carefully crafted periodic testing should reinforce key learning points.