I’ve recently read an excellent book called ‘Why We Sleep‘ by Mathew Walker. This book is based on decades of personal research into sleep carried out by Walker and others and references hundreds of studies on the benefits of sleep.
Sleep both before and after learning improves memory retention – this is because during NREM sleep, the brain moves what is stored in the short-term memory to the long-term memory – not only does it store new information during NREM sleep, at the same time it ‘clears’ the short-term memory so that it’s refreshed for new learning and memorisation to take place.
Sleep can also help with ‘riding a bike’ type skills…. Training and strengthening muscles can help you better execute a skilled memory routine.
Two experiments that demonstrate the importance of sleep:
Walker’s team recruited a group of healthy young adults and randomly divided them into a nap
At noon, all participants had to learn one hundred face-name pairs intended to tax the hippocampus, the short-term memory storage site. Both groups performed at comparable levels.
Soon after, the nap group took a 90 minute nap, while the non-nap group played board games or surfed the internet.
The two groups then underwent a second ‘face-name’ pair learning task. The nap group’s performance improved slightly, the non-nap group’s performance deteriorated.
The nap group had a 20% learning advantage over the non-nap group in the second round of testing.
Interestingly these findings are remarkably similar to one of the first sleep experiments ever conducted…. in 1924 Jenkins and Dallabach got two groups of participants to learn a list of verbal facts. Researchers then tracked how quickly participants forgot these facts over an 8 hour period – one group slept, the other stayed awake – there was a 20-40% memory retention benefit gained by sleeping compared to staying awake. Has been repeated numerous times and concerned.
Lessons from these experiments….
- If you want to study effectively, get a good nights sleep.
- Cramming when you’re short on sleep doesn’t work.
- Our education system, which insists on early starts for teenagers who are ‘hard-wired’ to want to go to bed later and get up later, is working against ‘the genetics of effective learning’.
The two experiments above are probably good examples of laboratory experiments with reasonably high ecological validity – at least in the sense that the quality of sleep once your asleep is going to be the same wherever you are.
For more advice on how to revise effectively, please see this post!
*Walker covers what is meant by a ‘good’ night’s sleep – it’s basically your usual 8 hours ish, but 8 hours actual sleep, which will probably require a longer ‘sleep window’.