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Desirable Difficulty

What Does “Desirable Difficulty” Mean?

Desirable difficulty is a term that was introduced by Robert Bjork in his 1994 study “Memory and metamemory considerations in the training of human beings” to refer to a theory of learning in which challenge is seen as the key to long-term learning. The foundational principle of this theory is that adding an aspect of challenge to learning activities will result in better long-term retention of information. In his 1994 study and in subsequent writings, Bjork draws a distinction between performance learning, such as cramming for a test and performing well in the short term, and true learning where the knowledge can be recalled and used in different contexts. Desirable difficulty incorporates strategies in which students are exposed to material repeatedly over the course of the class to improve recall, and thereby, retention. This may mean sacrificing short-term performance to achieve long-term results.

“…a theory of learning in which challenge is seen as the key to long-term learning”

According to this theory, however, not all difficulty is desirable. In order to be desirable, the difficulty should come from interacting with and processing information through repeated exposure to the concept, not from over-practicing or unnecessarily lengthy assignments. In other words, don’t confuse cognitive load with desirable difficulty. Having students memorize information such as formulas or dates for a single test when the object of the test or assignment is to assess the students’ ability to use the information rather than recall it, adds cognitive load rather than desirable difficulty because it affects the working memory rather than the long-term memory.

Ways to implement desirable difficulty into your courses

Below are some of the techniques associated with desirable difficulty and suggestions for implementing them into your classes.

  • Retrieval Practice – This is the practice of having students recall previously learned content on a regular basis. By asking students to recall this information, instructors are helping students to create a more long-term understanding of the material.
    • Implement retrieval practice in your classes by having students revisit topics throughout the semester. Easy ways to do this include low stakes quizzes, gamified review, creating (and using) flashcards, or written reflections. The key is to have students retrieve the content from their memories repeatedly rather than once for the test.
  • Interleaved Practice- This is the practice of learning overlapping or related concepts at the same time. The alternation of thought pattern and technique as the student switches  between concepts can be very challenging but it keeps the learner from becoming reliant on one process and makes their understanding of the larger concept more nimble.
    • Implement interleaved practice by mixing multiple concepts within the same assignment or test. For example, combining multiple methods of literary criticism into the same assignment encourages students to do more than memorize their characteristics; it lends itself to comparison and analysis. Rather than teaching concepts in the normal curricular trajectory of A and then B and then C. Combine the concepts for a richer, deeper understanding of how the concepts vary or work together as the case may be.

Bjork, R. (1994). Memory and Meta-memory Considerations in the Training of Human Beings. In J. Metcalfe & A. Shimamura (Eds.), Metacognition: Knowing about knowing. (pp. 185-205). MIT Press.

Download a PDF version of Memory and Meta-memory Considerations in the Training of Human Beings from Research Gate.