Write exam questions that create “desirable difficulties” to improve long-term learning

February 23, 2016

Write exam questions that create “desirable difficulties” to improve long-term learning

Desirable difficulties (Bjork, 1994) represent challenges students encounter during learning that may slow down progress in learning but produce large long-term benefits. For example, students who study in short sessions distributed across days and weeks require more time in advance of an exam to learn new material. The rate of learning may seem slow to students who distribute their practice, especially if they forget some material between sessions. In contrast, students who cram the night before an exam may believe they learned a large amount of material in a short time. Students who cram can earn a high score on an immediate test. However, the students who distribute their study will outperform students who cram when the test is delayed by as little as two weeks. Thus, some learning conditions (cramming) produce rapid changes in performance but do not produce long-term learning. Other learning conditions (distributed study) slow down initial acquisition but produce learning that endures.

Why is difficulty desirable?

The “Goldilocks Principle” describes the conditions that are “just right” for a planet to support life. Earth is a “Goldilocks” planet because it is neither too close to the sun (too hot) nor too far away (too cold); the temperature is “just right” for life to survive and thrive. Similarly, researchers argue that we need to find the conditions that are “just right” for learning. Vygotsky (1978) called this “sweet spot” the “zone of proximal development.” More recently, memory researchers identified “desirable difficulties” as conditions that are “just right” to engage students in the learning process and produce the best outcome for long-term retention.

The challenge instructors face is that learning activities produce rapid changes in performance and make learning seem easy but do not produce enduring retention. Other conditions make learning more difficult; they require more effort and progress feels slower. However, these conditions produce better retention. Similarly, task difficulty influences student motivation. Students may perceive tasks that are too easy as busy work and do not take these tasks seriously. Tasks that are too hard may overwhelm students and undermine motivation. Instructors need to find the balance between too easy and too difficult. They should design learning tasks that are “just right.” These tasks create “describable difficulties” that support optimal learning and challenge students enough to maintain interest and motivation.

Frequent quizzes create a desirable difficulty

Students will perceive any additional testing as a difficulty. Instructors might also perceive frequent testing as a difficulty. Writing and administering more tests takes time, even if the questions can be scored automatically. But these difficulties have benefits for learning. Bjork et al. (2014) reported that frequent testing in a course improved student performance on exams. Students who completed five in-class quizzes performed better on exam questions that assessed retention of concepts students answered questions about on in-class quiz questions. More importantly, students who answered in-class quiz questions also performed better on exam questions that tested related course concepts that were not directly tested with an in-class quiz question.

Write questions that encourage students to think deeply about course content

Maximize the benefit of frequent testing by writing questions that require students to retrieve and think about several conceptually-related course concepts. Use relevant disciplinary language and concepts when you write incorrect alternatives. Describe common misconceptions or articulate common misinterpretations of findings. Incorrect alternatives should be recognized as incorrect by students who understand the concept assessed by the question. These questions are a desirable difficulty because they force students to access and consider many course concepts. When question responses use concepts and language students see in the text and hear in lectures, they gain a superficial plausibility. Students must retrieve explanations for why these answers are incorrect. These challenges enable the questions to serve as learning experiences as well as assessing existing knowledge.


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

Bjork, E. L., Little, J. L., & Storm, B. C. (2014). Multiple-choice testing as a desirable difficulty in the classroom. Journal of Applied Research in Memory and Cognition, 3, 165-170. doi:10.1016/j.jarmac.2014.03.002

Vygotsky, L. S. (1978). Mind in society. Cambridge, MA: Harvard University Press.

02/23/2016 gb