Evidence review · 7 minute read

Does cognitive shuffling work?

Short answer: it might, and it's cheap and harmless to try, but the evidence is thin. There is one small study of the technique itself and some related research that fits the idea. Here's what each actually found, in plain terms.

We make a free cognitive shuffle tool, so we have an obvious interest in telling you it works. That is exactly why this page sticks to what the studies say and links to them so you can check. If you just want to know what the technique is, see what is cognitive shuffling?

What would good evidence look like?

To know a sleep technique works, you'd want several studies in which people are randomly split between the technique and a fair comparison, ideally including a group that does nothing new. Sleep would be measured both by diaries and, at least sometimes, by devices. The studies would be run by different teams, some without a stake in the result, and they would include a range of ages, not only students. Cognitive shuffling hasn't had that yet.

The main study: SLEEP 2016

The only study we know of that tests the technique by name was presented as a poster at SLEEP 2016, a major sleep research meeting, by Luc Beaudoin of Simon Fraser University and Nancy Digdon, Kelly O'Neill and Geoffrey Rachor of MacEwan University.

What they did

They recruited 154 university students (137 of them women) who said a busy mind kept them awake at bedtime. Students were randomly assigned to serial diverse imagining (the shuffle), to structured problem-solving (an established technique where you write down worries and next steps earlier in the evening), or to both. The shuffle group used an iPhone app that read out random words with an 8-second gap between them. Questionnaires on pre-sleep arousal, sleep effort and sleep quality were completed at the start, after one week, and after about a month.

What they found

• All groups improved from where they started on pre-sleep arousal, sleep effort and sleep quality.
• The shuffle did about as well as structured problem-solving. No difference between the groups was found, though the authors note the study had too little statistical power to detect one reliably.
• Students who tried both techniques were more likely to rate the shuffle as the more helpful and easier one.

What it can't tell us

• There was no untreated control group. People often sleep better over a few weeks simply because they are paying attention to sleep, or because their worst week passes. Without a group that did nothing new, we can't separate the technique's effect from those.
• The sample was narrow: university students, mostly young women, with racing thoughts rather than diagnosed insomnia.
• Sleep was self-reported on questionnaires; it was not measured with devices.
• It is a conference poster, not a full peer-reviewed journal paper.
• Conflict of interest: the poster discloses that Beaudoin is a director and shareholder of CogSci Apps, the company behind the mySleepButton app. That doesn't make the result wrong, but independent replication matters more as a result.

Fairly summarised: in one small study, the shuffle helped students about as much as a technique that already had evidence behind it. That is encouraging, not conclusive.

Related research: imagery as a distraction

The closest independent evidence comes from a 2002 study at the University of Oxford by Allison Harvey and S. Payne. They gave 41 people with insomnia one of three sets of instructions for a single night: occupy your mind with an interesting, engaging imagery task; distract yourself in general; or no special instructions. The imagery group fell asleep sooner and reported less frequent and less distressing pre-sleep thoughts than the group with no instructions. The authors suggested the imagery worked because it took up enough "cognitive space" to keep people from returning to their worries.

That wasn't a test of the cognitive shuffle. It used one absorbing scene rather than a stream of unrelated images, ran for one night, and was small. But it supports the shuffle's core idea: giving your mind a specific picturing task may crowd out the thoughts that keep you awake. We compare the two ideas more in cognitive shuffle vs counting sheep.

The theory behind it

A 2020 systematic review in Sleep Medicine Reviews, co-authored by Beaudoin, pulled together research on what goes through people's minds before sleep. It describes the normal transition to sleep as involving sensory imagery and a winding down of higher-level thinking, and notes that people with insomnia more often report planning and problem-solving thoughts at bedtime, which are also more unpleasant. It found that attempts to change pre-sleep thinking have had mixed results: some helpful, some negligible, some counterproductive.

That review is background, not a trial of the shuffle. It explains why the idea is plausible: the shuffle tries to replace the planning, problem-solving kind of thought with the loose, image-based kind. It does not show that the shuffle reliably achieves that. For the full mechanism, see how cognitive shuffling might help.

So, should you try it?

If your trouble is a busy mind at bedtime, we think yes, with realistic expectations. It costs nothing, takes a few minutes, has no known side effects, and the early evidence points in the right direction. Give it a week or so before you judge it, because the first nights tend to feel awkward.

If you have had trouble sleeping on most nights for three months or more, or it is affecting your mood, work or safety, please talk to a doctor. Cognitive behavioural therapy for insomnia (CBT-I) is the recommended first-line treatment and has been tested far more thoroughly than any bedtime technique, including this one. Snoring, gasping in your sleep, or severe daytime sleepiness are also reasons to get checked.

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