Is it harder to keep your balance in the dark?
March 25, 2005 9:48 AM   Subscribe

I'm a pretty good balancer (e.g. can stand on one leg for extended periods of time without falling over). However, I've noticed that my balancing ability degrades significantly in the dark (really dark, not just dim). My theory is that it's harder to keep your balance when your eyes don't have something to focus on. Thoughts?
posted by noahv to Grab Bag (23 answers total) 3 users marked this as a favorite
 
Sounds right to me. I have to put one hand on the shower wall when I shampoo my hair.
posted by mischief at 9:52 AM on March 25, 2005


Sure. Balance on one foot, then close your eyes. It becomes much harder.
posted by driveler at 9:59 AM on March 25, 2005


Balancing is a dynamic process. There are micro disturbances to which feedback needs to be applied to stabilise towards equilibrium. With eyes open, I suppose your reflexes have better information to adjust. I'm not (yet) convinced that with practice, one can't learn to balance based on a purely tactile loop. Only one way to find out.
posted by Gyan at 10:03 AM on March 25, 2005


From what I remember, the eyes are a major contributor to the vestibular system. Obviously, there are other components to balance, but visual feedback is used a lot. Vestibular.org has a bit on it, I'm sure there are other sources.
posted by RikiTikiTavi at 10:20 AM on March 25, 2005


Your theory is correct. Focusing on a stationary (this is key) object allows a consistent point of reference regarding direction and distance, which your body does not have good internal mechanisms for discovering unassisted.
posted by mkultra at 10:24 AM on March 25, 2005


It's called proprioception. I once had a physical therapy regimen that included a regimen of standing on one foot with my eyes closed for 30 seconds to enhance the proprioceptive sense and muscle groups around my injured knee. You can increase this sense through practice.
posted by jasper411 at 10:26 AM on March 25, 2005


"The human balance system is made up of three distinct sensory systems: Vision, Proprioception (gravity and stretch sensors found in muscles and joints), and the vestibular system (organs in the inner ear which detect position changes). Difficulties in any one of these sensory systems, or with the brain's integration of the inputs from the three, can cause one to feel dizzy, disoriented or unsteady" site not really worth visiting

A much more medically complex site states:
"A defect in one of these systems, or incongruous inputs amongst the systems can be compensated for by reliance on the other two systems. However, such a defect decreases the patient’s overall ability to adjust to incongruous stimuli between the other two fields. Also, a defect can result in a serious subjective feeling of disequilibrium in the affected patient until compensation for the deficit occurs."

The upshot seems to be that you can practice and get better at balancing in the dark.
posted by peacay at 10:26 AM on March 25, 2005


In yoga class, I can only do the balancing poses (asanas) if I keep my gaze focused on one point. Close my eyes, and my proprioception gets all out of whack and I fall over!
posted by abbyladybug at 11:28 AM on March 25, 2005


Try this: balance on one foot and look at it. You'll find it harder to maintain your balance while looking down than you will if you look outward, say at a point 20 feet away. I expect that the same effect happens in the dark.

Even more confusing when it's dark are the little lights that your brain will throw up into your visual field in the absence of outside light - try to focus on them to maintain a steady balance and you'll find that you get no positional feedback from them at all.
posted by Dipsomaniac at 11:36 AM on March 25, 2005


ObTrivia: There is apparently also a gender difference in balance. While everyone uses a combination of vision and inner ear to balance, one gender (on average) relies a little more on vision than the other. (I think it's women, can't remember).

I'm open to the possibility that this is an urban legend, but some fooling around we did a long time ago suggested (very non-scientifically) that there was merit to it.
posted by -harlequin- at 11:49 AM on March 25, 2005


i find it almost impossible to ride my unicycle at night. i have always blamed the darkness.
posted by RockyChrysler at 11:51 AM on March 25, 2005


On a more practical note, When cycling right next to a large bus that is moving/turning, you risk a fall if you don't concentrate on keeping the ground steady :-)

I've never fallen because of this, but it's always a weird (and neat) sensation - your body is saying "Opps - we're falling over, quickly - lean to the side to counteract it!", while your rational mind is saying "Ignore the body! Dont lean! Take it on faith that you won't fall if you don't counteract the fall".
posted by -harlequin- at 12:49 PM on March 25, 2005


I spent 10 years post doc working on this very problem. The balancing process is quite complicated, as noted by others above. There is a hierarchy of sensory inputs that are used to maintain one's balance. The most compelling is peripheral vision. In fact, the primary role of the vestibular system (organs of balance) is to stabilize the eyes during head movement so that a steady reference to the horizon is visible (personal discovery).

For example, a pilot flying an airplane in clouds has an instrument called the artificial horizon to provide such a reference. The biggest of these is only about 8" across. It takes a lot of practice to become proficient on these. An instrument I devised created a laser line right across the full instrument panel. This line was slaved to the aircraft's gyros, so that it moved exactly like the horizon moved were the pilot able to see it through the clouds. This display was so compelling in its ability to allow pilots to fly in serious turbulence that it became mandatory on the SR-71 and was even used at some point on the space shuttle.

All of this to say that the peripheral vision is the most compelling input to the system controlling balance. In the dark, however, one must rely on less compelling information, into which category the vestibular and proprioceptor signals fall. Just as people who become blind are able to greatly enhance their sense of hearing, they also enhance their ability to maintain balance from these latter two sources.
posted by RMALCOLM at 1:56 PM on March 25, 2005 [25 favorites]


By the way, RMALCOLM, Aviation Today is looking for you! Or at least they were in '99, maybe they've found you since.

The idea of accurately determining which way is up by fluid sloshing in my ears always sounded nutty to me (i.e. that visual cues would be way more effective). Incidentally, staying upright on a Bongo Board is much harder if you look straight up than if you look forward or down, and well-nigh impossible with your eyes closed.
posted by Aknaton at 4:18 PM on March 25, 2005


So it would seem, Aknaton. That is the first I have seen of that article. Thanks for pointing it out.
posted by RMALCOLM at 4:28 PM on March 25, 2005


Here's an experiment to try if you don't mind possibly falling over and injuring yourself. Stand on one leg, close your eyes (disabling your vision), tilt your head back (apparently this makes your vestibular sense a lot less effective), and do this on a bed or soft pillow (so that your proprioception of your ankle joint position isn't very helpful). You'll probably fall over immediately.

Interesting post about the vestibular system being used to stabilize vision, RMALCOM. Makes a lot of sense.
posted by hattifattener at 12:08 AM on March 26, 2005


There is another test I used to demonstrate the effectiveness of the peripheral vision. Roll up a piece of paper into a tube of about 1 1/2" diameter. Stand with one foot ahead of the other, heel to toe. Now close one eye and look through the tube with the other. You will notice how quickly you loose your balance when compared with looking ahead without the tube.

So now, we have 3 tests which can isolate the three components of balance. The tube to remove peripheral vision, hattifattener's pillow to remove proprioception and closing the eyes with head in normal position while standing on a pillow to rely solely on vestibular signals. The strength of each of these components will vary from person to person, but it should give each person a rough idea of what they are using.
posted by RMALCOLM at 7:25 AM on March 26, 2005 [3 favorites]


I like to walk on a 'slack line' It's a piece of climbing webbing secured between two points. It is like a tight-rope but usually more slack. Walking and balancing on one is very difficult but with practice you can get a lot better at it. I have found that if I focus on one point, I am a lot better. It seems much better to focus on a very small, precise and high-contrast point than a larger or more indistinct point. Try it.
posted by spirograph at 10:19 AM on March 26, 2005


Incidentally, staying upright on a Bongo Board is much harder if you look straight up than if you look forward or down, and well-nigh impossible with your eyes closed.
well-nigh impossible with your eyes closed.
Looked easy for a circus act. In addition, the act's roller was free from tracking on the board. For the finale the act placed the board on two rollers stacked one on top of the other in a cross pattern. The board and roller were called something else which I have forgotten.
posted by thomcatspike at 3:33 PM on March 28, 2005


This whole thread explains a lot that I previously intuited but never understood. I used to take the bus a lot on long haul trips, and I'm quite susceptible to motion sickness. It wouldn't be a problem during the day as what I saw corresponded to the motions my body felt. At night, however, I would suffer from quite a bit of nauseau. Over time I found that tilting my head back so that my line of sight was about 60 deg above horizontal mostly eliminated the motion sickness. Unfortunately that resulted in a sore neck, but hey at least I wasn't constantly dry heaving. That seems to correspond with what hattifattener is saying about the vestibular system.
posted by randomstriker at 3:40 AM on March 31, 2005


Spirograph that spot you watch while walking slack should be the end of the slack rope where it is tied down. BTW the slack rope is always slack, hence the name. Slack rope are also usually of a much thicker line than a tight rope. A tight rope should be tight enough to get a vibration off of when plucked. Slack rope, not so much.
posted by filchyboy at 9:46 PM on April 13, 2005


The board and roller were called something else which I have forgotten.

A rola bola perhaps?
posted by piskycritter at 3:12 PM on April 14, 2005


Next time you are accelerating down the runway in a passenger jet, close your eyes. You will probably feel yourself pitching backward long before the jet actually does (the effect is more pronounced in smaller jets and higher acceleration levels).

In your inner ear there are some small balls of chalk resting on hairs that bend. When you are sitting still, these allow you to sense your orientation. Accelerating forward, and tilting your head backward, are indistinguishable and that's what causes you to feel like the jet is rotating before it does.

The effect is so powerful at high acceleration that the Navy lost the first few steam launched jets from aircraft carriers as the pilots compensated by instinctively pushing the stick forward and flew into the sea, despite what their eyes were telling them. It is now a part of training to recognise it.

Our ear evolved when the highest force we experienced was chasing dinner, and night was something we lay down and slept in. The warranty is void if the device is used for purposes for which it is not intended.
posted by RichLyon at 12:13 PM on April 15, 2005


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