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The Trick of the Disappearing Thumb


Here’s a neat little trick you can play on yourself. In fact, you can only play it on yourself. Raise your arm (any of them), extending it over your head with an open palm, in such a way that you can’t see it.

Now, with your other hand, touch the tip of your nose with your index finger. Stay in this ridiculous position for around five seconds. Finally, raise your index finger and try to touch the thumb of your raised arm.

If you can’t find your thumb the first time you try, and starts to wander around, you will have the feeling that your thumb disappeared from your hand.

Congratulations, you have just played with your proprioception. That’s the sense of the relative position of the neighboring parts of the body, for instance, right now you know where your feet are even without looking at them. And we only notice the proprioception when it doesn’t work very well, as in the example below:


Much more interesting are the experiences with proprioception that lead to the rubber hand illusion. Or, in an even more extreme – and proportionally fascinating – version, where you fail to feel your whole body, in a sort of artificial “out-of-body” experience.

Thus, that classic scene of standing on one foot and touching the tip of your nose goes from proprioception to consciousness and out-of-body experiences. Tell that to the officer, he may find it a trip. [via Microsiervos]

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Posted in Science | 3 comments

3 Comments so far

  1. Brian October 15th, 2010 2:40 pm

    Hmmmm I tried this…..but nothing…It didnt work for me. Each time I reached up with my other hand after my index finger was on my nose, I found my thumb almost immediately. I re-read the intstructions and according to what is written I AM doing it correctly. Does it simply not work for some people?

  2. Sara July 31st, 2011 7:54 pm

    It didn’t work for me either. I even tried looking up videos of how to do the trick and didn’t find any. I must be doing something wrong or maybe it just doesn’t work.

  3. Jace January 6th, 2013 6:49 pm

    Nothing here. In fact, I tested myself before and after holding the position and my ability to find my thumb with the index finger of the opposite hand only improved after the nose position. Maybe being autistic makes this trick not what’s expected; I already have body mapping issues.

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