Or, "sense of balance" as Wikipedia calls it. I've been doing a little bit of experimentation. I know when I spin my chair around as fast as possible (until I reach a sort of "equilibrium" where I feel no acceleration, then stop, it takes a while for me to stop being dizzy, as would be expected. But I just recently realized that the sense of dizzyness is NOT due to my physical state (kinesthetic sense) because I can tell that I'm not moving. It's purely VISUAL. (And I'm kind of wondering if it's the same for other people.)
In the past, I realized that the feeling of which direction is "up" is not just a feeling but an actual visual perception. When you turn your head and look at a picture frame, you can still tell if it's on the wall crooked, even though your head is tilted. I had always wondered why when I tilted my head, my eyes were at an angle but it didn't seem like the world changed at all. Even when a person's body is at any angle, even upside-down, he or she is still able to tell whether something is upright or not. Clearly the visual is linked directly to the inner ear sense.
Well, when I was spinning on my chair the other day, I realized once I stopped that it seemed everything was at a DIAGONAL angle, and constantly looping visually (probably a result of trying to track the motion of the spinning visually prior to the stop). The angle gradually decreased until it finally looked level again, a process which took 15 seconds. I am guessing that it corresponds to the amount of fluid motion in the inner ear, and that I probably held my head at an angle while spinning. However, I did not get the same result when spinning to the right: instead the lines just seemed wobbly.
Then, strangely on-topic, a safety training presentation was posted on the Civil Air Patrol website about spatial disorientation: http://www.capmembers.com/media/cms/Spatial__Disorientation_1EB70933CA251.ppt Very informative!
There are types of motion that trick your body into thinking it's moving one way and is really not. I'm wondering how that's linked to the visual sense too, and if that's an integral part of making sense of it all.
So now, knowing all of this, I think more experimentation is in order. I want to try spinning left vs. right, head tilted vs. not, and eyes closed vs. eyes open. I'm wondering if the time it took to readjust differs for different people or different physical situations or awareness. If you have any personal experience or information on this, share it in the comments! And let the mad science begin! (Or, if these experiments sound like a bad idea and I might hurt myself, let me know too... I don't think it would do any harm, but I don't know everything.)
Oh and also, check out this cool thing about visual cognition: http://video.google.com/videoplay?docid=-7524529047833923429#
