Reference: Koh, A.W.L., Lee, S.C., & Lim, S.W.H. (2018). The learning benefits of teaching: A retrieval practice hypothesis. Applied Cognitive Psychology, 32, 401-410.

“The best way to learn is to teach.”  A favorite piece of advice proclaimed by educators, this principle has perpetuated for thousands of years, as reflected in the Latin proverb Docendo discimus (“by teaching, we learn.”)  A substantive body of literature focusing on the teaching effect clearly demonstrates that the opportunity to teach the to-be-learned information to others improves long-term retention of that information.  The benefits of teaching for learning and retention are undeniable, but the process that drives this teaching effect remains largely uninvestigated.  Teaching certainly helps us learn and remember, but why?

Researchers Koh, Lee and Lim (2018) aimed to answer this question by investigating the relationship between teaching and learning through the lens of retrieval practice.  Retrieval practice, the process of effortfully pulling information out of memory, was popularized as a study strategy by Roediger and Karpicke’s (2006) research. The authors found that testing oneself on recently learned information, such as taking a practice quiz or engaging in a “brain dump,” leads to better long-term retention of the information compared to conventional study techniques like rereading one’s notes.  Koh, Lee and Lim argue that the learning benefits of teaching might also be driven by retrieval practice.

Study, Teach, Learn

To test this idea, Koh, Lee and Lim asked 124 undergraduates to learn information from a science text.  All participants were told to study the text in preparation for teaching a video-recorded lecture.  Participants studied the text for 10 minutes and were then assigned to one of four testing groups: teaching without retrieval practice, teaching with retrieval practice, retrieval practice only, or a control group.  In the teaching without retrieval practice group, participants taught the information from the text in a video-recorded lecture from a pre-established script, which discouraged them from engaging in retrieval from memory.  In the teaching with retrieval practice group, participants taught the information in a video-recorded lecture based on their own memory of the text.  In the retrieval practice only group, participants wrote down as much as they could remember from the text, but did not teach a video-recorded lecture.  Finally, in the control group, participants simply completed arithmetic problems to fill the time.

All participants returned after a one-week delay, and were given a short comprehension test regarding the learned material.  They had not been informed of this final test beforehand, and thus were unlikely to have studied the information from the text further.

So, Does Retrieval Practice Drive The Teaching Effect?

Performance on the comprehension test was similar for participants who taught without retrieval practice (i.e., lectured from the existing script) and participants in the control group (i.e., did not review the material at all).

Performance on the final comprehension test was higher for participants who engaged in retrieval practice (either by lecturing without a script or taking a free recall test) than for participants who did not engage in retrieval practice. Both retrieval practice groups performed comparably to one another, suggesting that the benefit of teaching as a learning strategy is likely explained by the act of retrieving information from memory in the midst of a lecture.

Mean scores on a comprehension test after a 1-week delay. Scores were out of 25 possible points.

These results provide further evidence that using retrieval practice as a study strategy helps long-term retention compared to conventional study strategies.  More interestingly, these results paint a nuanced picture of the teaching effect.  Teaching from a script is no more effective than skipping study altogether.  Retrieving information from memory “on the fly” during a lecture is what facilitates improved comprehension of the material.

Putting It Into Practice

When using student-led teaching in a classroom setting, educators can consider leveraging retrieval practice as a part of the activity to enhance comprehension.  By understanding that retrieval practice likely drives the comprehension benefit during teaching, educators can also accommodate a diverse array of student needs.  That is, some students may have restrictions that preclude them from engaging in a teaching activity.  Students can benefit from self-guided free recall (e.g., a “brain dump” about the topic), which still employs the necessary retrieval practice process and maintains the same benefit!  Finally, students in search of new ways to study or improve their own learning can add teaching to their toolkits, but should do so with the understanding that teaching material to a friend will be most beneficial for learning if they try lecturing without notes or scripts.

Featured Image: Wokandapix from Pixabay. Accessed 4.8.2019. Link.

Additional Reference:  Roediger, H.L. & Karpicke, J.D. (2006) Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249-255.