A new meta-analysis does confirm memory retrieval can be beneficial for learning, but also shows there are limits:
- the frequency and difficulty of questions.
- Simply asking a question is not enough; students must respond to see a positive effect on learning
Probably you now want to know how much is too much? Well, you’re in for a bit of a disappointment I’m afraid, as you can learn from the press release which explains it better than the original paper imho:
“Frequency is a critical factor. There appears to be a trade-off in how often you test students,” Chan said. “If I lecture nonstop throughout class, this lessens their ability to learn the material. However, too many questions, too often, can have a detrimental effect, but we don’t yet know exactly why that happens or how many questions is too many.”
The answer to that question may depend on the length of the lecture and the type or difficulty of the material, Chan said. Given the different dynamics of a class lecture, it may not be possible to develop a universal lecture-to-question ratio. Regardless, Chan says testing students throughout the lecture is a simple step instructors at any level and in any environment can apply to help students learn.
“This is a cheap, effective method and anyone can implement it in their class,” he said. “You don’t need to give every student an iPad or buy some fancy software – you just need to ask questions and have students answer them in class.”
Chan, Christian Meissner, a professor of psychology at Iowa State; and Sara Davis, a postdoctoral fellow at Skidmore College and former ISU graduate student, examined journal articles from the 1970s to 2016 detailing more than 150 different experiments for their analysis. The researchers looked at what factors influenced the magnitude of this effect, when it happens and when the effect is reversed.
Why testing helps
There are several explanations as to why testing students is beneficial for new learning. The researchers evaluated four main theories for the meta-analysis to examine the strengths and weakness of these explanations from the existing research. The data strongly supported what researchers called the integration theory.
“This theory claims that testing enhances future learning by facilitating the association between information on the test and new, especially related, information that is subsequently studied, leading to spontaneous recall of the previously tested information when they learn related information,” Meissner said. “When this testing occurs, people can better tie new information with what they have learned previously, leading them to integrate the old and the new.”
Learning new information requires an encoding process, which is different from the process needed to retrieve that information, the researchers explained. Students are forced to switch between the two when responding to a question. Changing the modes of operation appears to refocus attention and free the brain to do something different.
A majority of the studies in the analysis focused on college students, but some also included older adults, children and people with traumatic brain injuries. The researchers were encouraged to find that testing could effectively enhance learning across all these groups.
“Memory retrieval can optimize learning in situations that require people to maintain attention for an extended period of time. It can be used in class lectures as well as employee training sessions or online webinars,” Davis said. “Future research could examine factors that can maximize this potential.”
Abstract of the meta-analysis:
A growing body of research has shown that retrieval can enhance future learning of new materials. In the present report, we provide a comprehensive review of the literature on this finding, which we term test-potentiated new learning. Our primary objectives were to (a) produce an integrative review of the existing theoretical explanations, (b) summarize the extant empirical data with a meta-analysis, (c) evaluate the existing accounts with the meta-analytic results, and (d) highlight areas that deserve further investigations. Here, we identified four nonexclusive classes of theoretical accounts, including resource accounts, metacognitive accounts, context accounts, and integration accounts. Our quantitative review of the literature showed that testing reliably potentiates the future learning of new materials by increasing correct recall or by reducing erroneous intrusions, and several factors have a powerful impact on whether testing potentiates or impairs new learning. Results of a metaregression analysis provide considerable support for the integration account. Lastly, we discuss areas of under-investigation and possible directions for future research.