evolution of vision, for balance?

[T'ai Chi]

There are a lot of things relating to the human body that help with balance.

I was doing some balance exercises yesterday, and realized how much vision plays a role.

I stood on one leg with the other raised in front of me bent at the knee, and grabbed that knee with both hands.

With eyes open, that is relatively easy. Then I closed my eyes, and it gets much harder- some 'wobble' enters the picture.

I started thinking, did vision happen evolutionwise in order to help aid balance?

 

[Mojo]

Vision is certainly involved in balance (hence, for example, motion sickness), but I would have thought that vision would have to be fairly sophisticated to help with balance. Your vision helps your balance by providing you with information about your movement relative to your surroundings. The probable early stages of the evolution of visual organs, such as light-sensitive spots with no ability to form an actual image, wouldn't really give enough information to help.

 

[Hellbound]

Actually, vision originated in species long before there was much need for balance, as well. Sea creatures and early land creatures that had no legs or few legs really didn't need much help with balance.

I think the role of vision in balance was simply an example of evolution using an already existing capability (vision) to improve performance of another (balance).

 

[MWare]

Interesting post. I found this article (http://www.geriatrictimes.com/g031209.html) which states:

In addition to allowing us to detect hazards in the environment, vision plays a direct and important role in stabilizing balance by providing the nervous system with continually updated information regarding the position and movements of body segments in relation to each other and the environment. When people stand with their eyes closed, postural sway increases between 20% and 70% (Magnusson et al., 1990; Paulus et al., 1984). It has also been found that moving visual fields can induce a powerful sense of self-motion and misleading visual cues induce significant increases in sway (Lee and Lishman, 1975).

Through personal experience I can confidently say, when the officer asked me to close my eyes and touch my nose, I suddenly knew it was going to be a long night.

 

[gmanontario]

Through personal experience I can confidently say, when the officer asked me to close my eyes and touch my nose, I suddenly knew it was going to be a long night.

I have no inner ear on the right side. If I close my eyes and do a roadside test I fail each and every time even stone cold sober. Twice now it's led to a visit to the police station during Toronto RIDE (Reduce Impaired Driving Everywhere) roadside checks. This is when you get pulled over at random for a breath test. I pass the breath test ('cause I don't drink) and fail the roadside if they give one.

Stupid officers never believe me when I tell them why I failed the roadside.

Edited to change fall to fail...

 

[Cecil]

This is a fascinating article about people who have lost proprioception, which is your body's sense of where its parts are. Proprioception is how you know where your arm is when your eyes are closed.

Without it, people are forced to relearn how to make all their movements by paying visual attention. They cannot walk or pick things up without watching where their legs or arms are.

 

[Mercutio]

This is a fascinating article ...

It sure is! Coolest thing I have read in a while...

My dad lost his proprioceptive sense for quite some time after a spinal infection. It came back only gradually and incompletely, long after motion and touch.