Featured article: Gupta, Pan & Rickard. Memory and Cognition 2021, Departments of Psychology at University of California Los Angeles, University of California San Diego, and the National University of Singapore, https://pubmed.ncbi.nlm.nih.gov/34545540/

The Qstream methodology harnesses the considerable power of two well-studied research findings from cognitive psychology: the spacing effect and the testing effect. The spacing effect refers to the finding that the presentation of training material over spaced intervals of time rather than in a massed session can significantly improve long-term retention of the material. The testing effect (also known as ‘retrieval practice’ in the research literature) refers to the finding that training programs which test participants on to-be-learned material generate significantly more long-term learning compared to training programs that have participants merely re-study the material.  

Qstream is often used as a method to reinforce critical information that trainees have learned in a prior session such as a lecture, podcast or video. One question we are often asked at Qstream is whether our methodology can also be used to teach new content. My research at Harvard Medical School has shown definitively that the answer is yes!  That said, we welcome more data that strengthen these findings.

The journal article cited above by Gupta et al focuses specifically on the testing effect and asks the research question ‘is the effectiveness of testing on the production of new learning affected by the participants’ levels of prior knowledge on that topic?’ To answer this, they conducted a series of three highly-controlled experiments among 95, 150 and 67 undergraduate students at University of California San Diego. The experiments had 3 phases: 

• Phase 1 (study, conducted at time 0) presented 40-80 word pairs (e.g. lime-salt) for 6 seconds each either 1 time, 4 times or 8 times.
• Phase 2 (training, conducted immediately after phase 1) presented the word-pairs again either in a re-study format (e.g. lime-salt) for 6 seconds or in a testing format (e.g. lime-? for 5 seconds and lime-salt for 1 second). For each student, the word pairs were randomly split in half: one half were presented in the re-study format, and other half were presented in the testing format.  
• Phase 3 (final test, conducted 48 hours after phases 1 & 2) presented all of the word pairs in a testing format (e.g. lime-?) and asked the students to submit their answers.  

Upon analyzing the results of the final test, the researchers found that those word pairs which were presented in a testing format in phase 2 were recalled much more effectively than those presented in a re-study format, once again providing evidence of the power of the testing effect. Importantly, they also found that the level of prior knowledge of the material (which they varied in phase 1 by giving students 1, 4 or 8 study sessions) did not affect the efficacy of the testing effect. As stated in their paper, the “results support the hypothesis that the advantage of testing over restudy is independent of the degree of prior episodic learning, and they suggest that educators can apply cued-recall testing with the expectation that its efficacy is similar across varying levels of prior content learning.”  

As with any research study, there are several limitations that should be considered when interpreting their results.  The 48-hour period between the study-training phases and the final test may improve the feasibility of these experiments on the college campus, but it limits the generalizability of these results to employee training where we want to optimize retention over months, not two days. Also, the study focuses on episodic memory, which is the ability to recall specific episodes from one’s personal past (e.g. details of a recent phone call). This is contrasted with semantic memory, which is the ability to recall knowledge of facts (e.g. the capital of Norway). The authors state that further work exploring this topic with semantic memory is warranted.

In spite of these limitations, Dr. Gupta and his co-authors should be commended for their rigorous, well-controlled experiments that once again provide evidence for the efficacy of the testing effect and also demonstrate that the efficacy of the testing effect is not limited by trainees’ level of prior knowledge of the to-be-learned material.  

For more information on how to improve knowledge transfer and recall, download our ebook, Scientifically Proven Strategies for Building Long-Term Knowledge Retention.