<p>This answer is going to be pure speculation as I don't have any references handy, but I would argue that fixing gaze on a single spot in the world provides three separate benefits for balance. All of these benefits are related to the fact that when you are not moving very much, fixating your gaze on a single spot in the external world also tends to "lock" the head, neck, and trunk into a single pose.</p>

<ol>
<li><p>This locking is useful because the head -- and thus the vestibular canals -- are essentially locked onto the position and orientation of the hips. When the hips move (e.g., because the leg under them wobbles), the vestibular system's movement is a direct reflection of that movement and doesn't have to be dynamically translated out of a moving, head-centered reference frame.</p></li>
<li><p>Similarly, with the head and gaze fixed on the external world, any motion in the hips or legs will translate directly to some sort of optic flow in the visual field. As with the vestibular system, this optic flow does not need to be dynamically translated into a separate reference frame as long as the head is fixed relative to the body.</p></li>
<li><p>Finally, I would argue that by locking down the trunk, neck, and head, more "bandwidth" (whatever that means) would be available in the motor system to provide control for the leg, hip, and trunk muscles. If the head and neck needed to be controlled simultaneously with the lower body, the overall control task would become more difficult.</p></li>
</ol>

<p>So, my argument here essentially boils down to the idea that by locking down the head and neck, fewer dynamic translations between reference frames are needed to compute the direction and magnitude of the control signals for maintaining balance. As a practical demonstration of this effect, imagine (or try, if you have lots of cushions around you) standing on one leg while shaking your head back and forth!</p>

<p>This argument breaks down if you imagine turning your head upward to watch a fixed spot on the ceiling while tying your shoe ; probably it would be harder to maintain balance in such a pose, even though the head and neck are fixed. So part of the maintenance of balance also seems to be having some sort of "canonical" or "easy" pose for your body to control, so not just any head-locked pose will do. But I think the fixed-head argument is a useful way to think about the issue.</p>

CC BY-SA 3.0
2013-10-03T17:45:18.333Z
2013-10-06T21:06:39.073Z
2013-10-06T21:06:39.073Z
lmjohns3
<p>If I'm trying to put a shoe on while standing with one leg, it's easier to maintain balance while staring at a single point (e.g., on the ground).</p>

<p><strong>Why does staring at a single point make it easier to balance on one leg?</strong></p>

CC BY-SA 3.0
2013-10-04T07:07:37.747Z
@what Want to convert that into an answer? I think it's more correct than the current answer and the upvotes on your comment seem to indicate others agree with me
ThomasH
CC BY-SA 3.0
2013-10-06T22:12:17.163Z
I like @what's answer but think it would be useful to be more specific about how looking at a single point helps to "register" the different feedback channels. Presumably all feedback channels are operating all the time ?
lmjohns3
<motor><eye-movement><vestibular-system>
Why does staring at a single point make it easier to balance on one leg?
Jeromy Anglim
# Why does staring at a single point make it easier to balance on one leg?

(Asked by: username_0 on 2013-09-30)

If I'm trying to put a shoe on while standing with one leg, it's easier to maintain balance while staring at a single point (e.g., on the ground).

**Why does staring at a single point make it easier to balance on one leg?**

**Tags:** motor, eye-movement, vestibular-system

> **Comments:**
> **username_1**: @what Want to convert that into an answer? I think it's more correct than the current answer and the upvotes on your comment seem to indicate others agree with me  
> **username_2**: I like @what's answer but think it would be useful to be more specific about how looking at a single point helps to "register" the different feedback channels. Presumably all feedback channels are operating all the time ?  

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## 1 answers

### Answer by username_2 on 2013-10-03. Score: 2

This answer is going to be pure speculation as I don't have any references handy, but I would argue that fixing gaze on a single spot in the world provides three separate benefits for balance. All of these benefits are related to the fact that when you are not moving very much, fixating your gaze on a single spot in the external world also tends to "lock" the head, neck, and trunk into a single pose.

1. This locking is useful because the head -- and thus the vestibular canals -- are essentially locked onto the position and orientation of the hips. When the hips move (e.g., because the leg under them wobbles), the vestibular system's movement is a direct reflection of that movement and doesn't have to be dynamically translated out of a moving, head-centered reference frame.
2. Similarly, with the head and gaze fixed on the external world, any motion in the hips or legs will translate directly to some sort of optic flow in the visual field. As with the vestibular system, this optic flow does not need to be dynamically translated into a separate reference frame as long as the head is fixed relative to the body.
3. Finally, I would argue that by locking down the trunk, neck, and head, more "bandwidth" (whatever that means) would be available in the motor system to provide control for the leg, hip, and trunk muscles. If the head and neck needed to be controlled simultaneously with the lower body, the overall control task would become more difficult.

So, my argument here essentially boils down to the idea that by locking down the head and neck, fewer dynamic translations between reference frames are needed to compute the direction and magnitude of the control signals for maintaining balance. As a practical demonstration of this effect, imagine (or try, if you have lots of cushions around you) standing on one leg while shaking your head back and forth!

This argument breaks down if you imagine turning your head upward to watch a fixed spot on the ceiling while tying your shoe ; probably it would be harder to maintain balance in such a pose, even though the head and neck are fixed. So part of the maintenance of balance also seems to be having some sort of "canonical" or "easy" pose for your body to control, so not just any head-locked pose will do. But I think the fixed-head argument is a useful way to think about the issue.


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