We usually think that we perceive the world as it is. Ok, so most of us know about various optical illusions that prove that the mind performs a lot of processing on the image and we may see something different.
In this post I wanted to talk about some less known phenomena, related to the feeling of touch. I’ll show 2 simple experiments that may surprise you.
I don’t remember where I know this from but it is possibly known.
- Cross the middle and the second fingers on your right hand. The middle finger should bend over the second. Its tip should be to the left of the tip of the second.
- Now touch the tip of your nose with the 2 fingertips. Your nose should touch right inside the space between the two fingertips.
What you will most probably feel is that you have two noses! Move the fingers a little bit up and down your nose tip to increase the effect of the feeling.
This is a most interesting effect and it is simple to explain. When you touch the tip of your nose in this way, you actually touch it with the left side of the second finger and with the right side of the middle. In the usual hand position, when the fingers are not crossed, these points look into opposite direction and are farther apart. It looks like the brain does not compensate for the crossing of the fingers that you performed in its interpretation of what your fingers feel. It just goes on with the ‘usual’ configuration of the fingers on the hand.
I hope you liked it.
This little strange phenomena I’ve noticed myself and have shown it to several people who approved its effect.
- Make the palms of your hand of different temperature. For this, either warm one hand on your body or touch something cold with it, like some metal surface.
- Now press the palms of the hands together flat, like a clap.
- Only with your hand feelings, can you distinguish which hand is colder and which one is warmer?
I can definitely feel that I feel a warm and a cold feeling somewhere in the palms of my hands but I can’t tell which one feels the cold. I can sure tell where in space around me I feel it. If I move my hands around (still clapped), the position of the feeling can be clearly defined but still not which palm feels what.
I have no hard scientific explanation for this but I think this way:
The brain interprets the feelings of touch to a 3D space, so that you would know where you touch something. If you were to touch a cold metal plate with only your right hand you would know where the plate is and you would know that the right hand touch it, since only the right hand is in the area. But when you press you palm together, they are both at exactly the same spot in the 3D space, so it’s not possible to distinguish which hand feels what. You feel cold and warmth at the same place in space and by ‘coincidence’ your both hands touch the spot, so you can’t tell which one feels what.
I found it very strange at first when I noticed this, since I assumed that because the nerve impulses go from each palm through its own arm they would be easily separated by the brain.
My conclusion of both experiments is that the brain make performs data processing on the touch sense, just like on the visual, and we may trick the brain to create ‘touch illusions’.
How did you succeed in the experiments?