If you have time, try to do the following: you need only a computer screen that is easy to rotate of 90°, and you need to have a mouse (does not work with a touchpad).
So, put your mouse on the lower part of the screen, then rotate the screen, and
1) try to move the mouse in order to reach some point on the screen (e.g. the button to minimize this window).
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The sensation you prove the first time is awkward, since if you move the mouse horizontally, the arrow on the screen will move vertically, completely disorienting you.
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2) Now, try to reach the same point in the following way:
just move the mouse "shaking your hand slightly", while keeping concentrated the mouse and on moving the mouse towards that point.
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You should notice that in this case the shaking motion gradually moves you to the wanted point, with much less effort than when you tried directly.
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I guess the mechanism explaining this is behavior is like follows: when you want to touch some precise point with your finger, the brain has some system to detect if your hand reaches the target in a subconscious way, computing the tiny deviations needed to reach it exactly. This probably is a process of "trial and error", i.e. the brain favours the movements that tend to the target.
Now, by shaking your hand, you eliminate the conscious part of your movement, and let free the inconscious error-minimizing corrections "do the work for you".
QUESTION: Does that make any sense? :)
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*How this experiment came to my mind: I recently was reading a PDF file directly from the laptop screen, and I had the idea to rotate the PDF and the laptop, in order to be able to see a whole page..