Friday, May 04, 2007

With Your Eyes Closed, Can You See Your Hand in Front of Your Face?

Puzzlement and confusion:

I close my eyes. I wave my hand in front of my face. It seems as though I can see the motion of my hand. Most people I've asked report the same.

It's possible that I do detect that motion. A certain amount of light penetrates the closed eyelids. I could be detecting differences in lighting as my hand passes before my eyes.

But on the other hand, most people, deep in a cave where there isn't a single photon to pierce the darkness, will report being able to see their hands moving in front of their faces. That this isn't a matter of picking up on visual stimulus is made clearer by our inability in such situations to detect another person's hand waved before our faces. It seems that our knowledge of the movement of our hand is somehow affecting our visual experience, or at least our judgments about our visual experience, without actually causing any visual input.

So: When my eyes are closed and I seem to detect my hand, am I actually visually detecting its motion? Or is what's going on more like what happens in a cave?

Let's do some science. Consciousness studies, in such matters, is pretty uncut. Maybe there's something out there on this, but I bet you'd have to dig pretty deep; and then you'd get a few weird articles from 1932 or something, or from a minor Japanese journal in 2001 -- articles that have never been cited, and that have strange, contradictory results. (I don't know this for sure, I'm just conjecturing based on past experience with similar questions.) If so, you can do novel experiments right there in your armchair.

Try facing different directions (toward a light source, away from a light source). Try closing your eyes more tightly, or occluding them with your other hand, or interposing an object between your eyes and your hand. That's what I did at least. I found myself sufficiently puzzled that I dashed downstairs and found a group of loitering undergraduates and had them all do it too! (This probably enhanced my reputation as a kooky professor.)

The results were complete uninterpretable chaos. For example, for myself: I seem to see it more strongly when I face a light source than when I face away. When I close my eyes tightly or put my other hand completely over them, I find myself uncertain about whether I have visual experience conditioned on the motion of my hand. If so, it is less. But when I put an occluding object between my eyes and my moving hand, say six inches in front of my face, I do think I still experience the motion of my hand, despite the fact that it can't be affecting me though that occluding object -- or at least that's how it seemed to me before I ran downstairs. I seem to be able to reproduce that effect only inconsistently. Others had different patterns of results.

If you're game to try, I'd be interested to hear your thoughts and experiences. Maybe I'll even work some of them into a presentation I'm hoping to give at the Association for the Scientific Study of Consciousness next month....

21 comments:

Justin Tiwald said...

The place to go to increase data quantity would be the nearest chapter of the NSS (National Speleological Society). This phenomenon is a source of perennial fascination for cavers. I was a caver in a former life (i.e., before grad school) and I must have experimented with the waving hand (and fingers, and feet, and everything else) several dozen times. Also, a little known fact about cavers is that they are generally geeky scientific types, and less the macho adventurer types. I have a hunch that most would be intrigued by a study like this, and therefore more inclined to cooperate.

Some quick observations, based of course on my own unreliable introspection:

1. My pre-reflective confidence that the hand is really there is much stronger in absolute darkness than when I merely close or cover my eyes. When I'm in absolute darkness with my eyes wide open, it really seems like I can see my waving hand. When I merely close me eyes, the confidence I have in the visual impression isn't so strong.

2. Something similar is true when comparing hand-waving with knee-tilting, leg-waving, etc. When I make a fist and wave it in front of my eyes, it really seems like I'm seeing a waving fist. When I wag a finger in front of my eyes, it really seems like I'm seeing a wagging finger. My visceral confidence is less strong in the case of legs and other appendages.

3. In absolute darkness, I always experience my hand as reddish brown.

4. There are other phantom visions that I can have in absolute darkness, sometimes even of nearby rocks or water-bottles that I've recently grasped. But again, I don't experience as much visceral confidence in these sorts of phantoms as I do in the case of hand-waving (broadly construed).

"Kooky professor" is a reputation to be proud of!

Eric Schwitzgebel said...

Very cool, Justin! Those are very helpful observations -- and yes, I'll try to talk to more cavers!

Anibal said...

I think is helpful for this issue the relevant investigation of what is called "eye-hand coordination" (e.g. some neurons fire when the hand and the eye are directed to the same direction).

Neurophysiologists investigating grasping skills in primates, inlcuding humans, for the purpose of applications in athletic excellence research, humanoid robots or just simply basic science; had discovered that extraocular propioceptive signals (e.g. in rough ways, any muscular activity even the hand in darkness) can induce an stimulation of the visual cortex.

A leading authority in these themes is the neurophysiologist Michael Graziano. So is not intriguing or completely nonsense to see our hand waving in total darkness especially for those "expert" people accostum to deal with enviroments which pose a difficult to our senses.

Eric Schwitzgebel said...

Very cool. I'll go look that up. Thanks, Anibal!

Pete Mandik said...

Very cool post, Eric.

I wonder what sorts of reports people give in conditions in which the hand is kept stationary but the eyes are moved?

I wish I would have known about the stuff with the cavers when I wrote my paper "Action-oriented Representation". My interest there was exploring different cases of perception that is relatively underdetermined by sensory input and augmented by action. In case you think you might find it useful, here's a link:

http://www.petemandik.com/philosophy/papers/aor.html

Eric Schwitzgebel said...

Neat. I haven't asked people about what they experience moving their eyes while their eyes are closed.

Speaking just for myself: My impression is that there's some sort of fluxuation of the darkness, but nothing localizable or objectual. Very hard to think about and describe!

I agree with the general gist of the essay above that the representationalist (though I myself am not one) has resources to address Noe-like (and Hurley-like) examples, by appealing to efferent signals. And yes, the caver phenomenon would be a good one to cite in this connection!

Jonathan Ichikawa said...

My first guess reaction is that our known motor activity has a major role to play in this sort of phenomenon.

A prediction, then, is that we'd be quite bad at "seeing" someone ELSE's hand moving in front of our faces.

Justin Tiwald said...

A prediction, then, is that we'd be quite bad at "seeing" someone ELSE's hand moving in front of our faces.

Without a doubt. This too is a familiar experiment among cavers. I wave my hand in front of Joe's face and ask if he can see it. Invariably, he is surprised to hear that I'm doing it. Once I tell him that I'm doing it, however, he's more likely to "see" it. But not so vividly as he will see his own waving hand.

And the game can go on and on. For example: I tell Joe that I'm now shaking my fist in front of his face and ask if he can see it, while in fact I'm using my hand to make a rude gesture. Joe reports that he "sees" a shaking fist.

In general, there are plenty of visual phantoms to be had in absolute darkness. I've often been convinced that someone was creeping toward me, or that there was a big outcropping to lean against. If I sit in a place long enough I can develop (involuntarily) a false estimation of the tunnel's dimensions and shape, even as I know and frequently remind myself that the estimation is far off the mark. I'm sure these sorts of experiences are familiar to just about anyone who has spent long periods of time deep underground (and with the lights out).

Eric Schwitzgebel said...

Very interesting!

I'm working on an essay, "What Do You See With Your Eyes Closed?", which will bring together various perplexities, weirdnesses, and divergences of opinion about eyes-closed experience. I'll definitely bring in some of the caver stuff (which I myself have also experienced a little) in connection with the issue in the original post.

I agree that it's very plausible that knowing your motor outputs has something to do with the caver phenomenon. But it's also plausible that you can detect changes in lighting with your eyes closed. The question in my mind is which of these is at play in the eyes closed hand-waving phenomenon, or if both in what way they interact.

One more thought: Maybe knowing visually that you couldn't possibly see your hand, for example if your eyes are squeezed tight shut, cancels out, as it were, the impression of vision derived from knowledge of motor output, whereas if the visual blockage is more subtle (an occluding object a few inches in front of your eyes) the impression of vision derived from motor output might be stronger.

Anonymous said...

I have something similar, but i took an extra step. After being able to see my arms move in front of me i decided to try blind folding myself and switching the lights off.

I hadn't a proper blind fold, i wish i had, so i took some brown bed sheets, folded them several times and then wore them, switched off the light and it was night time. The thing that amazes me is that not only can i see my hands in front of me, but i can also see some objects in the room. Its hard to explain what it tlooks like, but i can see sharp edges especially, however at the same time with no perception of distance and depth I cannot really know how far the object or edge is. Its strange but true, what else can i say =/ . And the way i think i can describe it would be like darker and lighter areas within the darkness, colour of the objects also matters. Thin eyelids could be it, but i also blid folded myself so i dont think so, also when i blid fold myself i close my eyes on top of that so i m not seeing through the bed sheets.

i havent shared this with anyone cause they ll think i m crazy or something, but if you could try it out and tell me the results you get would be cool.

-Anonymous person

Anonymous said...

Ha! Nice to see there are other people amazed by this phenomenon. I am a very skeptic person and I tend to agree with the neural / visual cortex activity explanation.

I even have some proof in that direction. When I lay in bed, without being able to sleep I sometimes wave my hands in front of my closed eyes AND in almost pitch dark. Apart from the fact that hardly any photons will reach my retina, I've experienced that when I have a clear picture of my hand and then open my eyes, I can see that the location is off by several inches. (hand seemed in front of me in one place, eyes opened it turns out to be somewhere higher, lower) This displacement is far more significant on the vertical plane.

Furthermore I concede that when I close my eyelids with force, the illusion gets weaker or is absent. This could be proof for the point made before, that your brain interprets the possibility for visuals from the force applied to your eyelids.

Eric Schwitzgebel said...

Very interesting, anon! I just tried it myself. With my eyes closed, the phenomenon seems to diminish for me. I do have a sense of where my hand is, still. It's hard to tell the extent to which that sense is visual, but if it is, it's pretty vague. When I open my eyes and turn on the lights, I my hand is in fact more or less where I thought it was (and more-or-less is all I'd thought I knew anyway -- I have no impression of a specific, erroneous sense of position). That was standing up in a darkened bathroom. I'll try it again lying down at night and see if the results are any different.

Anonymous said...

Hi, I am trying to find out why my 88 year old father sees entire events whenever he lays down on his bed with his eyes closed. He is definitely not asleep and as soon as he opens his eyes, it all disappears. He is in reasonably good health, and has never had any mental or psychological problems. Does anyone out there know what might be causing this phenomenon? He is very worried about why this is happening.
Sincerely,
Kansas

Christine said...

I just discovered this could happen! i seem to see my hand clearer when all the light is removed rather than when my computer is open in front of me.

Anthony said...

Hey.

I have always noticed this phenomenon as a kid and I use to play a lot with after images using an old camera flash under heavy blankets with different objects. ( light bulbs work great)
I recently started working out and like to use the weight machines with my eyes shut. While doing these strenuous activities I was noticing the greenish black outlines of where my hands are. I have been embracing this and opening my eyes quickly to see how accurate the registration of these images are. I also see the bars and handles of the machines, I feel its most clear when I am in motion. I don't have to be working out to see these I just happened to notice them very vividly while doing so.
I have been exploring this and based on my experience I do not think it has anything to do with light. I have been drawing some of the shapes that I see in different positions like stretching down with my arms hanging towards the floor. I am interested in the foreshortening that results and I have been drawing these shapes. They are almost like symbols that represent my position in space. Some are more abstract then others.
The most interesting and shockingly vivid of these images I have experienced are in the shower. I stand with my eyes closed and the shower head up high. I close my eyes and open my mouth letting the water into my mouth and shake my head hard and fast. The resulting image I experience is of the profile of two of my faces looking in towards each other with mouth open. Resulting in something that looks very much like the optical illusion of the vase/two profiles facing each other. Somehow the pressure of the water on my mouth gets read like flickering light and exentuates the experience.
Has anyone ever done this maybe you can try it out and let me know if im just a crazy person. My email is AnthonyFerraraNY@gmail.com Website is Antferrara.com

Anonymous said...

Strange. I occasionally search for information on this. Every so often when I'm laying in bed, I see things so clearly that I think my eyes have opened. When covering my closed eyes with a hand, it seems as if I can see right through it. It's not just hand movement.

It's not an after image because I can turn my head. It's so clear that a couple of times, I've tried walking around. It doesn't end well. I have absolutely no depth perception with closed eyes. Once I collide with something, I see what I thought was farther out, simply closer.

Everyone I've mentioned this to thinks I'm crazy. I'm willing to consider that my mind is simply filling in the environment I expect, similarly to the hallucinations one gets to compensate for the blind spot in the human eye; not unlike sensory depravation.

I'm even willing to go out on a limb and contemplate echo location, which has been proven capable in the blind. I guess I'll pop in some ear plugs next time I give it try, just to rule it out.

I found a class on Craigslist once that claimed to give answers and cultivate closed eye vision. It was entertaining but turned out to be some new-age clairvoyant belief system combined with Qi / energy. It wasn't anything like what I was hoping for.

If I can read blindfolded, I'm going for Randi's prize.

ToddinOC said...

well, all i have to say is that I'm glad I found this on the Web. I thought I was losing it. I realized a few weeks ago that I could see my hand (arm, fist, fingers) in the dark, with my eyes closed. I've never been a caver, btw. I started experimenting with it obsessively on a nightly basis. I finally put a wrap around my head and eyes to block out any possible light, and also closed my eyes. While a bit harder to see, by focusing my attention on seeing what was around me, by first focusing on my hand, i was actually able to see other things. I grabbed the blanket on the bed, and could make out the shape of the blanket as it lifted. I could see the edge of the bed. I tested my hand, of course, over and over again. Seems that by focusing first on my hand until I can "see" it made it easier to detect other things. When observing my hand (arm too), it seemed like it was the motion affected the ability to see it. No colors; just shadow of my hand/arm with what appeared to be tracers of energy outlining the shape of my hand/fist/arm/fingers. Like moving it around in water where ripples reveal the shape of the object moving. Seems motion is the key, regardless of the object I see. I think focusing on my hand to see it is what brings my brain to the place where it can pick out other things.

It's almost like sonar. Even in a cave you have sounds being made that would create vibrations off of surrounding objects. Seems I heard some evidence that humans may in fact have this ability, although not as finely tuned as, say, whales, dolphins, bats, etc. (also mammals, right?). I honestly don't think it is light that makes it possible for us to see things in absolute darkness, but rather sound.

Anyway, I will continue experimenting. Would be nice to know if anyone is actually doing research on this.

Todd

blackboxdisease said...

I experienced this for the first time last week and thought it may have been a neurological effect from serotonin toxicity. After a week of being ill, I had been laying down in my bed repeatably jumping in and out of the boundaries of vivid dreams, i, for no apparent reason, decided to place my hand in front of my face. My eyes were closed, but relaxed, looking forward (unlike the natural urge for the eyes to cross and tilt upwards) and with a ball cap covering over them, I was able to see a faint, black image of my hand contrasted over the black background of the nothingness that appears when the lids are closed. It startled me in a fantastic way as though I had discovered a hidden sixth sense. I could see each finger, see the hand as I rotated it, clenched fist, and each finger. The over-all description I could sum it up as a ghost hand, much like how amputees can feel ghost limbs.

Some other things I noticed during this is when I focused my attention and my eyes on what was going on other than seeing the hand, i noticed tiny dots that resembled the effect that low ambiant light has on NVGs when there isnt enough to excite all of the photons to produce an image. If you have ever used NVGs, i am sure you know what i mean and have a clearer understanding of what i am describing.

This phenonema has lead me to numerous insites of the human conscience as i use it to understand other neurological mysteries that i have experienced including seeing my thoughts as we are able to see our dreams when sleeping, (however only a few moments before actually entering the REM state and how i am able to be consciencely aware of this, i still do not know), and an instance where my brain would process objects seen on a medium like images on a monitor, as their respective name that it is associated with. For example, seeing the word "square" instead of what was really there: the two dimensional image.

I am glad I stumbled upon this blog post because I thought I had been the only one to experience seeing my hand with my eyes closed.

Shaun Dey said...

okey i dont know if you still are on this page lol but i just looked this subject up because i am doing this for a view years now i don't know what i'm doing so that's why i was looking to find answers to stumble op on your page what is good but in my experience i usually are sitting in the shower with my eyes closed en no lights i focus on the drops that come on to my head en with my mind in the darkness..(exually for me there is no darkness) don't know why i always see light i call it energy but until that point i just see energy not really what is in front of me until a view min later its strange some how i can SEE what is in front f me not only my hand waving but the pipe lining or were the soap is i can touch everything with out knowing were they were because before i turn on the shower i already turned of the light but what is strange is i can see the surrounding in light en the thing im looking at is darker that's why i can see it HOW THE HELLLLLL IS THIS Possible EN how can i try to get better at this if some one knows somebody that knows more about this please help me find him so i can ask him /her about this

Eric Schwitzgebel said...

Shaun you might also want to look at the many reader descriptions attached to this post:
http://schwitzsplinters.blogspot.com/2006/08/when-our-eyes-are-closed-what-do-we.html

Crazy eyes said...

What is the possibility that your are seeing your own aura? I have talked about this with my eye specialist, he guffawed the first time, said it was impossible. The next time I saw him he said " If you had not told me about this I would still say "Impossible"". You were right, in absolute darkness, whether you cover your eyes or not, you CAN see your hand moving, up and down or side to side.
When he told his wife about it she thought he was crazy. He had her try it, then discovered that he could see her hand and she could see his.

Mystery or?