Memory and Learning
Whether it’s developing skills, psychological techniques, or improving tactical knowledge, an athlete will rely on their memory to facilitate learning. The entire learning process depends on one’s ability to process, store, and retrieve information from memory.
Where does sleep fit in? Well, sleep plays a critical role in the consolidation of memory.
Sleep helps memory recall
Research conducted by Talamini, Niewwenhuis, Takashima, and Jensen (2008) showed memory recall was enhanced with sleep, and the sooner sleep was obtained after learning, the better the recall. Participants completed a face-location memory task. They were shown an image of a face while one of 8 dots were highlighted (see picture). There were 20 different 'paired' images in total that the participant had to remember.
Participants were split into two groups. One group completed the learning and initial test at 10am, and then had no sleep before a recall test 12 hours later, at 10pm. The second group completed the learning and initial test session at 10pm, and then slept before the recall test, which was also 12 hours later, at 10am.
Success was measured by how many correct answers were given in the recall test compared to the initial test. The results (see table below), show that the memory recall was better for the group who slept between the learning session and recall test.
Face Location Memory Task
Group
1
2
Initial
10am
10pm
Condition
No Sleep
Sleep
Recall
10pm
10am
Diff.
-7%
+1%
However, it's possible that the 'Sleep Group' produced better recall than the 'No Sleep Group' because of a reduction in interference. I.e., the 'No Sleep Group' had to deal with additional information and activities throughout the day which may have interfered with their ability to recall the learned information.
So the researchers tested two additional groups over 24 hours, with both having the same amount of awake (and possible interference) time. The results showed (see table below) that the group who slept soon after learning had better recall. So it appears sleep may have a beneficial influence on memory, and memory may be better when sleep directly follows learning, as the groups that slept soon after learning performed best on the recall test.
Group
1
2
Initial
10am
10pm
Condition
Wake - Sleep
Sleep - Wake
Recall
10am
10pm
Diff.
-12%
-3%
Changes in our brain
A study conducted by Yang Et al. (2014) showed (in mice) that sleep soon after learning a skill produced greater changes in synaptic plasticity (i.e., the formation of new dendrite spines in the brain) associated with learning and memory, compared to mice who were kept awake for 7 hours afterwards.
All mice completed a 40-trial training session on a rotarod (a device used to evaluate motor coordination of rodents) and then were allowed to sleep or were kept awake. When assessed 8 hours later the mice that had slept showed higher formulations of the learning-induced dendrite spines. When assessed a further 16 hours later (after all mice had the opportunity for sleep), the group with delayed sleep still showed significantly lower formulation of learning-induced dendrite spines.
The researchers increased the training of the sleep delayed group to 2 x 40-trial sessions. However, dendrite spine formation was still lower compared to the group that received just one training session but were able to sleep shortly after. When tested 5 days later, the mice who had a sleep delay had still not caught up, and performed worse on the rotarod motor coordination performance test.
Therefore, it seems sleep is beneficial to learning and memory, and sleep soon after learning may be an advantage. However, it is not always going to be practical to sleep directly after training. Which makes you think, what about naps? Fitting in a nap or two after training may be more easily achieved.
Even short naps help!
A study by Lahl, Wispel, Willigens, and Pietrowsky (2008) found naps improved declarative memory recall (memory of facts). Participants were tasked with memorising a list of 30 words. After an initial learning session, there was a 60 minute break before a recall test. Participants spent this break either:
-
Awake - spent the 60 minute break playing simple computer games.
-
Long nap - put to bed and woken after a 50 minute period (10 minutes before the recall test). The researchers measured the actual time the participants slept (e.g. it may have taken some time for a participant to fall asleep), and the average sleep recorded for this group was 36 minutes.
-
Short nap - put to bed and after approximately 5 minutes of recorded sleep were awoken. The actual average sleep recorded for this group was 6 minutes.
The results showed that recall after a long nap was significantly better compared to the recall of participants who stayed awake during the 60 minute break. Interestingly, even recall after a short nap of around 6 minutes was enough to signficantly enhance recall performance in comparison to the awake group.
MODULE SLEEP
The impact on performance
The moral of the story
The evidence suggests that sleep helps memory recall. As performing and learning new skills relies on our ability to remember, it would make sense to manage your sleeping patterns successfully to optimise your performance gains.
Learn more.....
References
Lahl, O., Wispel, C., Willigens, B., & Pietrowsky, R. (2008). An ultra short episode of sleep is sufficient to promote declarative memory performance. Journal of Sleep Research, 17 (1), 3-10.
Talamini, L.M., Nieuwenhuis, I.L., Takashima, A., & Jensen, O. (2008). Sleep directly following learning benefits consolidation of spatial associative memory. Learning and Memory. 15 (4), 233-237.
Yang, G., Lai, C.S., Cichron, J., Ma, L., Li, W., & Gan, W.B. (2014). Sleep promotes branch-specific formation of dendritic spines after learning. Science, 344 (6188), 1173-1178.