By Megan Sumeracki

(Cover image by NeurOptics, Inc., Pupillometer Results Screens, from Wikimedia (CC BY-SA 4.0))

If you read our blog even occasionally, you know retrieval practice has many benefits. Retrieval improves learning and memory, reduces test anxiety, and can protect against learning losses associated with stress. Today’s blog post is about another benefit of retrieval practice, reducing processing load.

Péter Pajkossy and colleagues (1) published a paper with two experiments examining retrieval and processing load. They asked whether retrieval practice improves efficiency by allowing the individual to reduce the attentional resources needed. High demand on our limited processing resources can lead to reduced performance, and so it would be good news if retrieval practice reduces the demand on the limited processing resources that we have. To measure processing load during the experiments, the researchers used pupillometry. In general, when the pupils are constricted, it is a sign of a lower processing load compared to when pupils are more dilated.

For more on pupillometry, visit this page on the Arizona Retina Project!

The Experiments

In both Experiments 1 and 2, Hungarian undergraduate students learned randomly paired Hungarian-Swahili word pairs. Using word pairs allowed the researchers to present multiple discrete trials (40 pairs in total) and to be able to clearly determine students’ accuracy on each trial. This is particularly important with physiological data, like pupillometry. Randomly pairing the words ensured that students could not use associative strategies (like elaboration) during the experiment.

Both experiments involved three phases: a learning phase, a practice phase, and a final test phase. The only difference between the two experiments was that in Experiment 1 the final test was completed five minutes after the practice phase, and in Experiment 2 the final test was completed one week after the practice phase. The computer and remote eye-tracking system recorded pupil size throughout the experiment.

Learning Phase

In the learning phase, students were instructed to try to memorize the pairs. They learned the pairs across five cycles, with each of the 40 pairs presented once during each cycle. The students then completed a 5-minute distraction task and moved on to the practice phase.

Practice Phase

The practice phase also had five cycles, with each pair occurring once per cycle. During each cycle, the students practiced repeated retrieval of half of the pairs and repeated studying of the other half of the pairs. Thus each pair was either repeatedly retrieved five times or repeatedly studied five times across the entire practice phase. During study, they again were shown the pair and instructed to memorize it. During retrieval, they were given the Swahili word and instructed to say the Hungarian word.

Final Test Phase

After a delay of either 5 minutes (Experiment 1) or 1 week (Experiment 2), students completed the final test. Students were given the Swahili words and asked to say the Hungarian pair.

Results

During the practice phase, students showed improved performance across the repeated retrieval cycles. At the same time, there was a graduate decrease in pupil dilation. Generally, this result suggests that across repeated retrieval recall of the information becomes more automatic.

When the final test phase was only 5 minutes after the practice phase, restudying the pairs led to greater test performance than repeated retrieval. However, when the final test was 1 week later, repeated retrieval led to greater performance compared to restudying. These results are fairly typical, and show that repeated retrieval is best for longer-term learning and memory.

In both experiments, pupil dilation was smaller when students were being tested over the pairs they previously retrieved compared to pairs they previously restudied. This was especially true for items that were successfully retrieved five times during the practice phase.

What Does This Mean?

These results suggest that repeated retrieval leads to decreases in processing load. Repeated retrieval was associated with decreased attentional control, meaning that students then have more attentional resources at their disposal.

This may help to explain why retrieval practice seems to work just as well, or even better, for students with lower working memory capacity. Working memory capacity is tied to attentional control, and lower cognitive resources is often associated with lower performance. If retrieval practice decreases the need for attentional control and frees up some of these limited resources, then it follows that those with a lower resources to start would benefit from this learning strategy! Still, because retrieval practice is associated with so many different benefits related to long-term learning, it certainly need not be restricted to students with lower attentional control.

References
(1) Pajkossy, P., Szőllősi, Á., & Racsmány, M. (2019). Retrieval practice decreases processing load of recall: Evidence revealed by pupillometry. International Journal of Psychophysiology, 143, 88-95.