I'm surprised nobody has mentioned the problem with this study is it is not blind.
Clearly the sleeper knows if they are wearing an eye mask with holes that let in light, or if they are wearing a complete eye mask.
I work in the neurotech/sleeptech space, and it should be possible to do this study in a double blind method.
In a sleep lab, with EEG, monitor the users sleep state. When they are in any non-wake state ambient light could be brought into the room. In one instance, no light is applied, in another light is applied.
Don't use the usual camera's that are used in a sleep lab. In such a method the trial is double blind, but also much more expensive than the method used.
I like this idea, as well as the irony of the original study being not blind. ;)
Another possibility might be to design the functionality into the mask itself. When it detects the user is asleep, it could open up to let in light (or not) based on which cohort the user is in.
The detection could be done by having sensors in the mask itself, or it could just pair with the user's existing fitness/sleep tracker of choice via Bluetooth.
I get the pun, but you highlight a potentially assumed unnecessary absence of additional cohorts - how does this effect people who are blind, both blind from birth and those that have lost their sight at some period of their life, and for a select period of time.
Are we to assume that this study excludes these two additional cohorts, and if so why or how has that been established?
I have tried many masks and they always irritate me when I'm sleeping. I never manage to get to sleep easily with one on so I'm not sure your assumption everyone thinks they sleep better with a mask on is true. If the study used a more transparent material and didn't tell the participants or small holes I would think light was certainly the issue. Why do you think the participants were guessing correctly what the study was observing - it seems likely they were not told and went in without judgment - I certainly wouldn't have noticed if the mask was a bit thin? It seems more likely to be a real difference, we know circadian rhythms are controlled by light and food timing so I don't see why it wouldn't be a correct result.
I have experimented with eye masks before, but found that they either made contact with my eyelids or caused me to sweat during sleep. However, I have now discovered that wearing a black t-shirt over my eyes works remarkably well. This allows for proper air flow and prevents sweating, while also avoiding any contact with my eyelids.
Amazing, this is exactly what I’ve been doing for the last 30 years. I just grab a thin, lightweight black or dark tshirt. The nice thing is if I’m traveling I don’t even have to think about it because I’ll likely always have a tshirt handy.
I seriously cannot sleep without doing this now. The feeling of light incident on my closed eyelids while trying to sleep is quite uncomfortable.
I wear a Manta when I need an eye mask, which has cups around the eyes so your eyelids do not contact anything. Recommended if you'd rather have a proper solution.
I also use a Manta. Some versions can be quite steep in price, but it’s helped tremendously since we live in apartment with a lot of light pollution spilling in
I agree with this 100%. I don't have issues with things touching my eyelids or with being too hot, but I'm a fidgety sleeper and regular masks always fall off, and then I'm too sleepy to use two hands to put them back on. A black tee shirt that I can lazily throw back over my eyes with one hand works a million times better for me than any mask I've ever tried.
I've tried many different types of eye masks, and it has taken me a while, but I have finally found ones that are both comfortable and do not contact my eyes or eyelashes while sleeping. There are many companies who make similar eye masks, but the ones I like look like these: https://a.co/d/igoKTZR
My only problem now is that my CPAP mask is transparent, and so some light bleeds through there. If I could find an opaque CPAP mask, then I would be able to block out all outside light. As it is, I find that putting a pillow over my head over the CPAP mask blocks out most of the rest of the light that would otherwise get through the mask, and because of the CPAP mask I am still able to breathe underneath the pillow.
I can tell you, it makes a huge difference for me to be able to block out the light. Almost as much of a life-changing event for me as getting the CPAP in the first place.
I'm not sure I follow? They were not wearing a mask in all treatments, such that it isn't like they were relying on tricking people by having a mask that didn't actually block light.
I agree that it could be something other than the mask. For instance, it could be that it is the simple matter of having them try something that led to an increase. But I'm not as clear on how this is an obvious "flaw" with the study.
Or are you saying you would want the double blind to fully rule out light, and we would be back to asking "why did the masks do something?"
GP is saying the participant knows they are/are not wearing the mask when they go to sleep and this could skew the results, e.g. by expecting to get a better night’s sleep via the sleep mask, they experience less sleep anxiety, sleep better, learn better.
This tells you something different than “ambient light while sleeping negatively impacts learning.”
If there was a placebo effect, I would expect there to be a significant difference in the participants' self-reported sleep quality, but there was not:
> Sleep diary data revealed no differences in the number of hours slept while wearing the eye mask (7.15 ± 16.66) or the control mask (7.18 ± 16.82; t(23) = −0.11, p = .914, N = 24). Likewise, there was no significant difference in self-rating of sleep quality (eye mask: 3.13 ± 0.19 vs control: 2.84 ± 0.16; Z = −1.53, p = .131, N = 31).
Those sleep quality measurements barely overlap at 1 SD. I don't care if anyone says it's not statistically significant; the trend is enough that I would not be convinced without a lot of additional data which pushes the mean values much closer together.
Right. But I would (edit: not) say that is a flaw with this study. Just something else we can try and rule out.
That is, if you did manage to "double blind" it and got no difference in treatments, that means we don't understand the mechanism in this study. It does not, necessarily, mean that there are no results in this study. RIght?
The placebo effect is really powerful. When you see a study like this, one of your first questions should be "how can I tell whether or not this is just placebo?"
Sorta. If you are worried about placebo/nocebo, than I see obvious paths where you wind up in with your incentives being to lie to people. Either about the possible ill effects, or about enthusiasm that they will work.
Yes, we have evidence that this influences things. That is usually why people replicate without telling people why they were doing something. In this study, they didn't say "we are testing you with masks to see if they make you test better." It was more, we are testing you with and without masks to see if we spot differences. I could easily envision some folks expecting the result to go the other way.
More, if that is the concern, you need to test doing that. Don't make it blind, reverse the message. Tell them you expect them to be less alert wearing a mask, and see if that holds.
Could work. I don't know enough about the specifics of experiment design for sleep research. You could also try things like transparent masks + lies ("they filter specific wavelengths"), etc. Studying people is awfully hard. Lying is generally allowed as long as you do the right things as far as advance ethics review and design (and usually informing the person later, etc.).
To be fair, the problem you are bringing up is larger than just sleep research. https://examine.com/summaries/study/0AKk3d/ is an interesting study that was looking at what is often thought of as a much more active drug.
My question is ultimately on whether that is a flaw in this study, or more to study? :D I'm probably placing too much weight on the word "flaw?"
Studying people is so complicated with so many weird results you really just need to make it double blind, you won't be able to reason your way out of it reliably.
> Why are some things only effective if we believe them to be so?
Are they though? I used to think so until I skimmed Wikipedia article on placebo some 5 minutes ago. According to the article (as of now), there's been plenty of research on placebo done in the past couple decades, which revealed... the most mundane reality you'd expect: placebo effect impacts perception of symptoms, and can only do as much as a transient change in perception can. Apparently, the old studies that ascribed all kinds of big effects to placebos, were failing to account for regression to the mean.
Now, I haven't checked the sources, but I'm inclined to believe it - it feels right. The possibility of placebos being meaningfully effective on the targeted condition itself felt like bad writing[0] - the same phenomenon should be giving us all kinds of superpowers, which we don't see. I mean, when you get drunk, you may tolerate pain better, but your skin doesn't turn into kevlar with steel inserts just because the drunk you believes you're impervious to knives and bullets.
--
[0] - Like in fiction, when you discover the author didn't think through the consequences of a minor plot point they're making - a plot point that, extrapolated ever so slightly, would instantly break the main story, and/or disrupt the entire fictional universe.
Certainly some effects are clearly only explainable by physical changes. Cognitive effects, though, it feels are a bit easier to see will be in the realm of placebo.
Telling people something won't work could cause it to not work. Which is terrifying.
Edit: I am slow to realize it may have sounded like "shut up" was directed at you. My apologies. I meant that more for the generic voice of caution that is as often very valuable. And i am very nervous on what it implies for general health reporting. How many more people are sick because they think they should be? What can you even do with that idea?
Right, and if someone is healthier because they ate their spinach, that seems to imply we should encourage mistakes in that direction?
That is, if we were to reduce the negative effects reporting, but increase the positive ones, would that bias the world in that direction? (That make sense?)
There are some weird quantum effects which allows your mind to "steer" the future into the direction you want. You can choose from a set/distribution of possible futures.
Look no further than the multi billion dollar health supplements market for placebos that don’t do anything
But seriously the only ways off the top of my head to mobilize placebos is to lie to people which doesn’t seem worth the squeeze. They just lead to more misconceptions.
> But seriously the only ways off the top of my head to mobilize placebos is to lie to people which doesn’t seem worth the squeeze. They just lead to more misconceptions.
But that's literally what marketing does, not just for supplements, but in general. The limits of what can be achieved through lies and persuasion are well-mapped now. There is a tension between what marketers would like to do, and what the law allows them to, but it's a tension over marginal effectiveness - the illegal methods are only slightly more effective than the legal ones. There are no psy-corps placebo mind control superpowers, known or hypothesized - if there were, then regulations around advertising and fair competition would look more like regulations around access to enriched fissile material or highly infectious pathogens.
Skimming Wikipedia, it seems that effort was spent, and what it revealed is that "placebo effect" is mostly bunk - any discernible effects exist only patient's perception of symptoms and things influenced by it (e.g. patient calming down); any change in objective measurements seem to be better explained by plain regression to the mean (e.g. patient just getting better on their own).
As for exploiting the perceptual aspects for good and bad, well, that's a really really well-explored ground - we've been at it for thousands of years. Religion, folk medicine, homeopathy, or the modern bullshit fads like fitness, healthy food, spiritual exercise philosophies, etc. - they all build up huge emotional frameworks around core interventions that, by themselves, have slight to no effect. They are big money printers, tho.
It's this huge amalgamation of marketing and junk pseudo-science, a quasi-religion that gets people involved emotionally to the point of defining their own identity in terms of their diets and exercise activities. It surrounds a small kernel of good ideas about health and nutrition, but it leads people to it in a round-about fashion, extracting money on the way.
Couldn't the protocol be set up like a psych experiment in which you misdirect the subject (making the sleeping mask incidental from the subject's perspective)?
I'm assuming your objection is that the research biased the results by informing the subjects that they are testing the effect of sleeping masks on "episodic learning and alertness"?
I don't think it matters that they knew. Either ambient light hits your eyes or it doesn't. What about other factors that make it sleep-mask specific like the feeling of textile over your eyes, or the strain of the strap around your head? Your experiment tests other things.
The placebo effect is strong, especially for things like alertness. There’s been studies purposefully showing that participants who think they’ve been given a mental stimulant perform better in cognitive tasks in a statistically significant way, for instance.
Are people who have been given the information that they're using a placebo trully convinced of that or do they just have a mental barrier preventing them from further acknowledging it and just resign to respond: "yeah, I know it's just a placebo"
But a true placebo effect is only _if_ the ailment _did not_ heal if you hadn't taken the placebo. Otherwise, you're just taking a nonactive ingredient, and your body is merely healing itself from the ailment.
A true test of placebo effect must be one where you'd have a group who does not use a placebo, and a group that does! But then how would you study it blind?
> A true test of placebo effect must be one where you'd have a group who does not use a placebo, and a group that does! But then how would you study it blind?
Maybe a better (and possible) test would be to give everyone the placebo, but divide participants into three groups. One would be told they're given a real treatment, the other would be told they're given a placebo for the real treatment, and the third would be told they're given a sugar pill for no specific reason other than to see what happens.
1+2 would then tell you about whether or not knowing if you're getting a real treatment or placebo matters; 2+3 would tell you how much knowing you have a problem to treat in the first place matters.
The point of the wider thread is that placebo generally does not work. It only may create an illusion that it does - but that illusion alone does not cure the underlying problem (unless that problem is highly affected by your perception, at which point it's not really a placebo, but a proper treatment).
They may have heard of "placebo effect" (i.e. the popular take on it), and figured "hey, this means it might still do something; better not dwell on it too much".
We do not live in the wizarding world. There is a limit to how much your perception can influence your own body, or physical processes around you. That applies in both directions - belief alone can't move a mountain, but it also can't stop the excavators already moving one.
I would argue that because your body is the one doing the perceiving, there is likely no limit to the ability of our perceptions influencing our bodies. Belief alone can't move a mountain, but is that not because the belief is not strong enough, rather than because beliefs don't physically have hands with which to hold the pickaxe?
Are you familiar with a study where merely changing something improved outcomes for a while? They made lights brighter and workers were more productive for a bit, then they dim them back down, workers are again productive but for a bit. First they though oh, let's just make lights brighter everywhere eh? but it turned out nah. Probably it's just workers feeling like you are doing something for their benefit, so once you stop it's back to the baseline.
It seems important to eliminate that possibility, because otherwise sleeping mask or not literally doesn't matter and it's just about doing something and the study is simplified to "caring about sleep improves sleep". Which can be totally true even if bollocks per western medicine tradition to date, but then the study should be about that and not about sleeping masks eh?
> Evaluation of the Hawthorne effect continues in the present day.[24][25][26][27] Despite the criticisms, however, the phenomenon is often taken into account when designing studies and their conclusions.[28]
Regression to the mean, which apparently (per Wikipedia article on placebo) is what really happened in those old studies that made people think "placebo effect" is a big deal.
Wouldn’t the way around this be to mislead participants about what is actually being measured, or to have some sham device be involved to throw participants off?
Deception in scientific studies is controversial but not universally forbidden. Here's a link diving into the issue for psychological/social science studies. I'm unsure how it impacts medicine research, but I imagine it's a similar attitude.
Eye masks are also a valuable travel hack. Hotels tend to have LED light coming from different places - smoke alarms, clocks, key card slots etc - and it's always a gamble how much sunlight gets through the windows. It's much easier to put on an eye mask than worry about how to black out the room.
Similar story with any form of transport, where the various light sources are largely outside your control.
The newer "3D" eye masks provide full blackout and stays on without much trouble. Well worth keeping in a travel kit alongside earplugs.
It's not just the specifics of the environment but the fact that if you acclimatise to using the mask at home, when you travel you are maintaining perfect consistency with your home environment while sleeping, which I find to be beneficial. With a bluetooth mask you can add some white noise so even extraneous sounds aren't bothering you.
But wearing an eye mask is nigh impossible for restless sleepers; it slips off constantly. My best solution after trying many masks is an old t-shirt draped across my eyes, which inevitably slips off but at least doesn't drag elastic bands over my face.
Anyone know of research showing the effectiveness of varying levels of darkness in a room, from complete blackout to fairly dim?
First line of the abstract: Ambient light can influence sleep structure and timing.
So of course the eye mask isn't necessary at all, reducing the ambient light is the key. Mask is one option, but black out curtains (in most areas) and eliminated or shielding any light emitting devices in the room is key.
It's incredible how bright a room can be with the lights off in the dead of night.
I use small strips of electrical tape to block led lights from small appliances I keep in my bedroom. I wish more companies were thoughtful in reducing the amount of light their electronics emit in a default state.
i toss and turn all night and this thing stays on most of the time, is incredibly comfortable, and i am so grateful i received it as a gift (would never have bought for self)
As a side sleeper I had the opposite experience unfortunately, so YMMV. The Manta Pro is touted for side sleepers, but I've used both the pro and original and they both suffer from the same problem: it still slips around and the walls of the eye cups press into my eyes as I sleep. I gave it a few weeks of waking up with soreness and misaligned vision. No amount of fiddling with eye cup positions or strap tightness helped. The thickness of the strap is a fundamental design problem with the Manta approach, even with the expensive tech fabrics on the pro. It's overbuilt.
After trying about 10 other sleep masks, I ended up with the Alaska Bear Silk Two Strap [1] which has straps so thin they're imperceptible, and a much more effective retention mechanism, for a fraction of the price.
I have used (and loved) the Alaska Bear Silk mask for years, but it does come off occasionally. I’m absolutely going to try the double strap one now, thanks for sharing!
Thanks for posting this. I've been looking for a mask with eye cups but couldn't find anything decent on Amazon.
Have you tried the Silk one? I'm tempted to get that one instead of the Pro since the materials sound nicer, but the site is really unclear about the differences...
Hmm… I just bought one but I notice their page has a quote of customer praise saying they can no longer sleep without one. That seems a little bit troubling
Earplugs and sleep masks are habit forming, but speaking as a light sleeper, it's better than the alternative. It's easy enough to always have one on hand, and makes a big difference in my restfulness.
I've been using a Manta Sleep mask (no speakers) for the last year and half, and love it. Unlike the cheap eye mask, it doesn't have an elastic strap that eventually gets out of shape. And it blocks 100% of light for me.
As a side sleeper, I can't use masks with speakers or even long ear plugs, as they put enough pressure on my ear cartilage that they make sleep uncomfortable.
Got one and it’s pretty much the bees knees. A nice evolution over their earlier generation, which I also own. It even seals about 99% of light over a full task CPAP Darth Vader setup
The masks that are cloth all the way around and have velco work for restless sleepers and side sleepers, or at least that has been my experience. I was on a medication ages ago that made me restless. Look online for the masks that are 100% cotton cloth and have a thin padding inside. Avoid the masks with the eye-shaped face and avoid the masks with the stretch band as they do exactly as you describe.
Have you tried the Manta sleep mask? Expensive but never slips, does the black out thing, and is super comfortable and very breathable in hot weather. Improved my sleep significantly.
You need to spend a bit of money on a comfortable and large mask. I have used this one in the past (Amazon link but it seems to be "unavailable" now: https://www.amazon.co.uk/gp/product/B07TL7VYSM).
I’m not sure it would work for your scenario, but I use a Buff [1], which is a soft fabric tube designed for wearing as a kind of face mask for outdoors activities. They’re really soft and comfortable as an eye mask and don’t get too hot or slip off. I fold it over 2 or 3 times to make it darker. Couldn’t sleep without it!
I've been covering my eyes almost my whole life, and I agree with you that a t-shirt is far more effective than almost any sleep mask I've found. And yes, I've tried the fancy ones.
A shirt drapes comfortably, it fits you easily and snugly without pulling too tight, it's also always available
I have likewise found that a T-shirt around the head tying the arms is an order of magnitude better than a mask and really helps me with the last couple hours of sleep when things are getting lighter.
I had the same problem with masks. I eventually bought a pair of swimming goggles and covered it with tape to block out light. It rarely slips off and is reasonably comfortable.
For many people, light prevents melatonin production. Maybe not for everyone, also know an old friend in school who can sleep through bright sun right in the face.
I've had the same problem, but found a solution: a standard eye mask that would slip off on its own, held in place by one of those 'Buff' tube scarves.
My personal hack is using a Buff [1] instead of an eye mask. It’s a soft fabric tube designed for wearing as a kind of face mask for outdoors activities.
They’re really soft and comfortable as an eye mask and don’t get too hot or slip off. There’s no elastic stream involved and it’s really slimline so you barely feel it. Also they’re cheap!
I use a dark coloured one and fold it over 2 or 3 times to make it darker. Couldn’t sleep without it, nor could a few people who I’ve introduced to it!
Yeah that's correct, I owned one for skiing and happened to try reusing it in frustration after being awoken by the light coming in through the curtains.
I had no idea they had such a large range! I just use a basic original, full size one, made out of thin material. Full size means you can fold it over two or three times to make it block out more light, I'm not sure a half size would work so well but I've never tried one.
I think it would be the "Original EcoStretch" model, though I can't say for 100% certain as I bought mine in an outdoor wear shop and just bought the cheapest, thinnest, darkest one.
I think I just needed to be sure you used the full size one.
I'll look for a dark one and make sure it is a model for warm climates (I suppose a winter/ski version could be a bit too much to wear in bed, especially folded).
Buffs are used like this on backpacking trips as well. Especially if you sleep cowboy style without a tent and you're staring a the moon and the starts.
Living in Iceland, where in the summer time we get midnight sun effectively for a few weeks, I've slept with darkening blinds and an eye mask for some years now.
I've gotten so habituated to it that I almost can't fall alseep without one.
I worry about this aspect of my sleep. I have gotten used to sleeping in the quiet and darkness and I worry that over the years I might get used to this and not get proper sleep without it. I used to sleep pretty well in a noisy and with distracting lights when I was living near a busy street.
Been using eye masks for almost a decade now. Current fav is the Manta Sleep with the big cups but always looking for something better. Any recommendations?
I'd be curious if anyone has experience with the Manta Sound mask, specifically if they're really able to sleep on their side without uncomfortable pressure from the speaker between pillow and ear. Hard to imagine it working for anyone but back sleepers.
I never said it was the purpose. It's obviously not the purpose of them, I'm saying that I find that it adds just a touch more required activation energy to check my phone, so I am a bit less likely to.
(1) the truncated axes hide what a small effect size it seems to be and (2) even though they state the p-value is significant, eyeballing it there seems to be a really wide variance that is almost overlpaping b/w the two situations.
It seems to me like a marginally significant result with a very small effect size.
If it's just the amount of light as per abstract,I assume darkened room would be equivalent I.e. There's no magic additional benefit of mask itself (pressure / touch / etc)?
I don't understand how 'eye mask' made it into the title, if it's all just about light.
Here in Germany, you get window shutters ("Rolladen") on every window and that's that
Funny, in Germany most "old" houses don't have shutters, from my small sample of living in 4 or 5 German houses. Many people from the south of Europe complain about that when traveling to Germany.
and often in France, ones that you can close from the outside. Moreso for blocking out the sun in summer time and security rather than night pollution.
I don't get the fake shutters in North America. Especially the ones that wouldn't even cover the window if they could move.
The whimsical swinging shutters you see in the US: yes.
The mechanically or electrically-closed rolling shutters called "Rolladen" in German, and installed on all but the cheapest new construction in Europe: when properly installed, those things can black out a room with the sun shining directly through the window.
I've been to some houses where the shutters had no gaps and they fit the window frame so well that virtually no light made it in, even during the day. It was surreal waking up in the morning, thinking it was still night time, then checking the clock only to see it was 8AM. A great feature to add to a house if you ask me.
Alternatively, IKEA makes a great little set of curtain tracks (VIDGA) you can attach to your ceiling to get full floor-to-ceiling blackout in a room, similar to many hotel rooms.
That might be possible with good blackout curtains, except for the LEDs on damn near everything. Even in my own room at home, I have to remember to cover the USB charger that I use for laptop and random other devices. When I travel, it's a nightmare - clock radios, TVs, microwaves, and especially the lights built in to many GFCI outlets in bathrooms. I used to bring a roll of electrical tape for exactly this reason. Masks are the solution that works everywhere to block light, though they're less than ideal in other ways.
Absolutely agree. If I recall, there used to be an actual standard regarding this, but it was (is?) widely ignored and never enforced. I remember the time before blue LEDs with quite some fondness.
I bet that with your eyes closed, the difference between "black out blind dark" and "no light" isn't much. I bought black out blind about 5 years ago and they're amazing. If I'm in my parents house or staying in a hotel during summer, I get crappy sleep and I'm wide awake at 5am.
I might mention that, believe it or don't - a living skull is translucent, and our brains can detect light all by themselves. So a mask is good, but not nec a whole solution.
In old experiments, just the light coming in under a door diminished melatonin in mice.
This is of course an entirely useless study, because participants know when they are wearing a mask.
Logic dictates that very likely wearing the mask has no effect at all, and it is in fact other factors influencing quality of sleep. It would make sense to look into those, and it is very surprising it was not already done from the beginning.
E.g. Obviously a participant can not use their mobile phone or other screen devices if they are wearing a mask, and the mere fact they are wearing the mask may force them to do the one thing they can do: sleep.
In other words, it could simply be that the mask itself incapacitated and prevented other activities from being carried out by the participant. Equal or better results can be achieved if participants are told to concentrate on sleeping. Heck, you might even pay them just to sleep so they do not stress about the fact they have to waste time sleeping – this alone should yield some interesting results.
> E.g. Obviously a participant can not use their mobile phone or other screen devices if they are wearing a mask, and the mere fact they are wearing the mask may force them to do the one thing they can do: sleep.
This sounds like you describing the mechanism rather than rejecting the idea that a sleep mask helps. IOW, it may help because it "enforces" better sleep hygiene.
Firstly, it’s not “entirely useless”; it just has a slightly lower quality of evidence than a study that was blinded for participants. However, some things are quite difficult to practically blind – and this (not unreasonably) is one of them.
Secondly, you raise lots of interesting hypotheses that might contradict the findings of the study. These would indeed be interesting directions for further similar studies. However, in the meantime, a study (even of moderate evidence quality) is probably more valuable than off-the-cuff hypotheses.
(My low quality n=1 anecdote: i’ve discovered that I am quite light sensitive while sleeping. so measures which minimise ambient light improve my quality of sleep. Whether this is blackout curtains or a sleep mask is more situationally dependent.)
The subject did sleep at their homes, which means the noise level was not controlled, and it seams not even measured (no noise word in the article).
The effect may be real, but I would like to see it corroborated in a more controlled environment.
Couldn't they just not tell the percipient what they were testing. Then you wouldn't know that someone else had a mask or didn't. That would remove the placebo effect.
I remember a 'body-hack' fad around inducing lucid dreaming via sleep masks. IIRC, it used EMG sensors to detect eye muscle movement and then it would flash an LED mounted inside the mask in an attempt to slightly wake you up during REM. Can anyone speak to the method's efficacy?
I built this a few years ago: https://fellerts.no/projects/eog.php. It only gave me intense nightmares. It was a cool project though, and I'm sure it could work for some people.
Interesting aside speaking of lucid dreaming- at least one of the authors of this paper is a lucid dream researcher - Karen Konkoly at Northwestern. Another people she coauthored studies conversing with lucid dreamers while they're mid-dreaming. Interesting stuff.
While the study may be bunk, anecdotally, finding a sleeping mask that worked for me (stayed on, wasn’t uncomfortable, kept all light out) has been a game changer in sleep quality. Better sleep has always brought more benefits to my day, so I am a believer in the mask.
I guess compared to blackout curtains/blocking leds/draft stopper/synced partner when you wake up you could have natural sunlight in the room. ( "Participants were asked to sleep with open shutters/curtains for the entire duration of the study.")
But they didn't test for that here.
The studies conclusion seems to be blackout curtains either cost $$$ or take a bit of effort to install, mask is cheap/easier.
Sleep is good, people sleep better when as much light is blocked as possible. It's a conclusion that is known.
And by contrast, perhaps just as important to get plenty of natural light during the day to regulate melatonin production - an anti-cancer and immune system enhancing agent whereas artificial light at night can be a real problem.
https://cmbl.biomedcentral.com/articles/10.1186/s11658-022-0... and many other reports.
I’ve been wearing an eye mask during sleep for the past year and I’m afraid I’ve become slightly addicted to it. Sleeping without it is terrible. I think this is one of those things that when you make the switch, it’s difficult to ever go back.
Clearly the sleeper knows if they are wearing an eye mask with holes that let in light, or if they are wearing a complete eye mask.
I work in the neurotech/sleeptech space, and it should be possible to do this study in a double blind method.
In a sleep lab, with EEG, monitor the users sleep state. When they are in any non-wake state ambient light could be brought into the room. In one instance, no light is applied, in another light is applied. Don't use the usual camera's that are used in a sleep lab. In such a method the trial is double blind, but also much more expensive than the method used.