Sleep makes relearning faster and longer-lasting

According to a new research by researchers at the University of Lyon, it is a good idea to get some sleep in between study sessions. The findings of the study that were published in Psychological Science, a journal of the Association for Psychological Science, reveal that such a strategy can make it easier to recall what you studied and relearn what you’ve forgotten, even 6 months later.

Stephanie Mazza, a psychological scientist at the University of Lyon explained that the result of their study suggest that interleaving sleep between practice sessions can reap a twofold advantage – it will help in reducing the time spent relearning and ensuring a much better long-term retention than practice alone. Some previous researches are known to suggest that sleeping after learning is definitely a good idea, but this latest study reveals that sleeping between two learning sessions greatly improves the end learning.

There have been some researches on repeated practice and sleep and it has been suggested that it can help improve memory, however there is not much research on how repetition and sleep influence memory when they are combined. The researchers working on this study assumed that sleeping in between study sessions can help in the relearning process and make it more efficient, thereby reducing the effort needed to commit information to memory.

For this study, the researchers chose 40 French adults who were randomly assigned to either a “sleep” group or a “wake” group. All participants were given 16 French-Swahili word pairs in random order at the first session. The participants were given 7 seconds to study each word pair after which the Swahili word appeared and participants were prompted to type the French translation. The correct word pair then appeared for 4 seconds. Any incorrectly translated word was presented again and again till they were correctly translated. After the initial session, the participants were given 12 hours rest and then were made to complete the recall task again, practicing the whole list of words until all 16 words were correctly translated.

The difference between the wake group and sleep group was that the wake group participants completed the first session in the morning and the second session in the evening of the same day while the sleep group completed the first session in the evening, slept, and completed the second session the following morning.

There was no difference in the results of the two groups – they didn’t show any difference in how many words they could initially recall or in the number of trials they needed to remember all 16 word pairs. However, the data after 12 hours has a different story to say. Participants who had slept between sessions recalled on an average about 10 of the 16 words, while those who hadn’t slept recalled only about 7.5 words. For relearning, the sleep group needed only about 3 trials to be able to recall all 16 words, while the wake group needed about 6 trials.

In the end both groups were able to learn the 16 word pairs, but it was seen that those who slept in between the sessions could do it in less time and with less effort. Mazza opined that memories that were not explicitly accessible at the beginning of relearning seemed to have been transformed by sleep in some way, which helped subjects to re-encode information faster and to save time during the relearning session.

The researchers added that the benefits of sleep could not be ascribed to participants’ sleep quality or sleepiness, or to their short-term or long-term memory capacity, as the two groups showed no differences on these measures.

The benefits reaped by the sleep group by sleeping in between study sessions seemed to have a lasting effect. There were follow up recall sessions a week later in which participants from the sleep group outperformed their peers. The sleep group showed very little forgetting, recalling about 15 word pairs, compared to the wake group, who were able to recall about 11 word pairs. Even when the recall test was carried out 6 months later, the benefit was still noticeable.

The study concluded that it is a good technique to sleep in between study sessions as it helps to remember information over longer periods of time with less study.

Having trouble sleeping? Here is how you can fall asleep fast.

References:

https://medicalxpress.com/news/2016-08-relearning-faster-longer-lasting.html

https://www.psychologicalscience.org/index.php/news/releases/sleep-makes-relearning-faster-and-longer-lasting.html