Learning by taking practice tests can protect memory against the negative effects of stress, according to a new study. Scientists from Tufts University in the US conducted experiments involving 120 individuals who learned a series of words and images by retrieval practice showed no impairment in memory after experiencing acute stress. Participants who used study practice, the conventional method of re-reading material to memorise it, remembered fewer items overall, particularly after stress. “Typically, people under stress are less effective at retrieving information from memory,” said Ayanna Thomas, associate professor at Tufts. “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,” said Thomas. Our results suggest that it is not necessarily a matter of how much or how long someone studies, but how they study,” said Amy Smith, graduate student at Tufts. The research team asked participants to learn a set of 30 words and 30 images. These were introduced through a computer programme, 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. 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. 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. The study appears in the journal Science.