Retrieval Practice Buffers Memory Impairment From Acute Stress

Taking practice tests, a strategy known as retrieval practice, can protect memory from negative effects of stress, scientists from Tufts University report.

Senior study author Ayanna Thomas, Ph.D., associate professor and director of the graduate program in psychology at Tufts, says:

“Typically, people under stress are less effective at retrieving information from memory. We now show for the first time that the right learning strategy, in this case retrieval practice or taking practice tests, results in such strong memory representations that even under high levels of stress, subjects are still able to access their memories.”

The research team asked 120 student participants to learn a set of 30 words and 30 images. These were introduced through a computer program, which displayed one item at a time for a few seconds each.

To simulate note taking, participants were given 10 seconds to type a sentence using the item immediately after seeing it.

Retrieval Practice Vs. Studying

One group of participants then studied using retrieval practice, and took timed practice tests in which they freely recalled as many items as they could remember. The other group used study practice.

For these participants, items were re-displayed on the computer screen, one at a time, for a few seconds each. Participants were given multiple timed periods to study.

After a 24-hour break, half of each group was placed into a stress-inducing scenario. These participants were required to give an unexpected, impromptu speech and solve math problems in front of two judges, three peers and a video camera.

Participants took two memory tests, in which they recalled the words or images they studied the previous day. These tests were taken during the stress scenario and twenty minutes after, to examine memory under immediate and delayed stress responses.

The remaining study participants took their memory tests during and after a time-matched, non-stressful task.

Memory Retention And Stress

Stressed individuals who learned through retrieval practice remembered an average of around 11 items out of each set of 30 words and images, compared to 10 items for their non-stressed counterparts. Participants who learned through study practice remembered fewer words overall, with an average of 7 items for stressed individuals and an average of a little under 9 items for those who were not stressed.

“Even though previous research has shown that retrieval practice is one of the best learning strategies available, we were still surprised at how effective it was for individuals under stress. It was as if stress had no effect on their memory,” corresponding author Amy Smith said.

“Learning by taking tests and being forced to retrieve information over and over has a strong effect on long-term memory retention, and appears to continue to have great benefits in high-stakes, stressful situations.”

While a significant body of evidence has previously shown that stress impairs memory, few studies have examined whether this relationship can be affected by different learning strategies. The current results now suggest that learning information in an effective manner, such as through retrieval practice, can protect memory against the adverse effects of stress.

Although the research team used an experimentally verified stress-inducing scenario (Trier Social Stress Test) and measured participant stress responses through heart-rate monitors and standardized self-reported questionnaires, they note that stress effects are variable between individuals and additional work is needed to expand on their results.

The team is now engaged in studies to replicate and extend their findings, including whether retrieval practice can benefit complex situations such as learning a foreign language or stressful scenarios outside of a testing environment.

Amy M. Smith, Victoria A. Floerke, Ayanna K. Thomas
Retrieval practice protects memory against acute stress
Science 25 Nov 2016: Vol. 354, Issue 6315, pp. 1046-1048 DOI: 10.1126/science.aah5067

Image: Tufts University/Kevin Jiang