‘Why We Sleep’ and Memory

I’ve recently been reading Matthew Walker’s Why We Sleep, and will probably be recommending it to everyone for a while. Walker summarises the current scientific literature on sleep, both in terms of of what it does, its health benefits, and the risks of sleep deprivation. He suggests that modern industrial and post-industrial society consistently devalues and disrupts sleep, and advocates for action on every scale to remedy this.

I was prompted to read the book after hearing it mentioned in Andrew Holocek’s exploration of dream yoga with Michael Taft on DY. Holocek draws on both Buddhist and Western thought on dreams, and discusses the potential of lucid and intentional dreaming to enrich a meditation practice. I heard a brief introductory talk on dream yoga by Khandro Déchen at my first Aro retreat back in June, and was intrigued by the idea that you could treat lucid dreams (which often occur naturally for long-term meditators) as an opportunity to practice. I had some knowledge of the topic from checking out the r/LucidDreaming community at one point, but the focus there is mostly on fantasy and wish fulfilment. I like Holocek’s angle that just as a meditation practice is about becoming more lucid and aware in your waking life, it would make sense to extend that lucidity to sleep as well.

The very idea of lucid dreaming may prompt a natural skepticism for some, but Walker actually devotes a few pages to it in Why We Sleep, and discusses an intriguing study that strongly suggests its veracity. The researchers used MRI scanners to observe the waking brains of participants while clenching their right and left hands. During REM (rapid eye movement) dream sleep the body remains motionless, but the eyes move; hence the name. Using pre-arranged eye movements, participants were able to indicate they had achieved dream control. They then signalled an intent to dream about clenching their left and right hands, and the MRI scans showed up with a corresponding image to that seen while awake. I can’t say that I’ve had the opportunity to experiment with this myself yet, but it’s good to be reassured that I wouldn’t be attempting the impossible!

Another aspect of the book that interested me was the relationship between sleep and memory. The contrast between the four progressively deeper stages of NREM sleep (non-rapid eye movement) and REM seems to hold the key to how the brain processes memories. The brain cycles between these two kinds of sleep during the night in roughly 90 minute blocks, with a broader pattern of more NREM sleep at the beginning of the night and more REM later on. The slow waves of NREM sleep pulse from the front to the back of the brain, with bursts of higher activity at the end of each wave, known as ‘sleep spindles’, which seem to shield the sleeper from external noises. It seems that one result of this kind of sleep is transferring memories from a sort of short-term storage in the hippocampus to more long-term storage in the cortex. REM (dream) sleep on the other hand is a bit more complicated, although much better theorised and understood in recent years. It currently looks like its main role is of integrating the memories which have been received while awake and stored in NREM sleep, bouncing them off each other in novel and creative ways.

It would be very interesting to know what kind of effects meditation practice might have on memory, with the caveat that it would probably depend on the type of practice, the type of memory, and the intentions of the subject. The main Aro meditation practice is Shi-nè, in which, if I’ve understood it correctly, the aim is not to grasp at feelings and discursive thoughts, but to allow them to play out in spacious awareness. I’ve found several times that in the minutes immediately after practice, my mind seems to make spontaneous connections between the thoughts and ideas that have been rolling round my head. I’ve heard it said anecdotally that people who meditate a lot don’t need as much sleep, so I do wonder if meditation and sleep have some potential overlap in their effect on the mind-body complex.

Following on the heels of Why We Sleep, I listened to Andy Matuschak on the Venture Stories podcast, discussing with Erik Torenberg the fact that people often remember very little of what they read, even when they believe it’s important and worth remembering. Matuschak is an advocate of spaced-repetition systems like Anki for learning and retaining knowledge, and suggests that the non-fiction book needs a new technological paradigm which deliberately combines ‘reading’ with ‘understanding’. The principle of Anki is that if you truly want to remember something, you need to repeatedly recall it at particular intervals, and it seems that this system does actually dramatically increase your ability to remember. For a brief while there was a tongue-in-cheek war of words on Twitter between advocates of this sort of memory work, characterised as ‘first brainers’, in opposition to ‘second brainers’, a term derived from Tiago Forte’s ‘Building a Second Brain’, which focuses on building up a resource base of knowledge in the form of notes. Cf. Walker, it seems pretty obvious that your original meat-brain does its best to both retain and synthesise memories while you sleep, so it would only make sense to work on enhancing both capabilities in your daylight hours. The only difficulty is deciding what’s truly important in our information saturated world, and the best way to work with it.img_1213.jpeg


Other recent reading: Iain Sinclair’s Lights out for the Territory, a brilliant collection of discursive, digressive and polemical essays on London, and Ali Smith’s wonderful Winter, her seasons quartet being the best thing to come out of Brexit so far.

ICYMI: I put out a mix of ‘party’ tunes last week.

Photos from last week’s chilly walk around Malham Cove in the Yorkshire Dales.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s