Touch Illusions

A recent paper (available as a pdf file) by Vincent Hayward in Brain Research Bulletin lists more than twenty types of tactile illusions that can be experienced using very simple equipment available in any hardware store. Some of the descriptions of the illusions unfortunately are rather technical, but here's a summary of a few of them:

The Aristotle Illusion: Cross your fingers and touch your nose. You may feel two noses. (It didn't work for me.)

The Comb Illusion: Lay your finger on top of the teeth of a comb. With your other hand, run a pencil back and forth against the teeth. You should feel "the sensation of a raised object moving on the finger when, in fact, since the teeth have a constant length, the skin is sheared but indentation is invariant along the line."

The Curved Plate Illusion: Move a plastic card or match box back and forth across the pad of your finger. It should feel straight. But if you see-saw the object up and down as you move it across your finger, it should feel curved.

(via Developing Intelligence)

Science

Posted on Mon Feb 18, 2008


Comments

The nose trick didn't work with me either.
Posted by Mark  on  Mon Feb 18, 2008  at  06:56 PM
The nose one worked for me; you have to cross your fingers just right.
Posted by Phil  on  Mon Feb 18, 2008  at  07:39 PM
I remember when we were kids, my sisters and I used to do this thing where one of you lays on the ground on your tummy and you'd hold your arms up for the other person to grab. Then you'd stay like that for several minutes or as long as you could stand it. Then after a while the person holding up your arms would slowly lower them to the floor and it felt like you were passing through the floor.

Just thought I'd share. I like stories! 😊
Posted by Nettie  on  Tue Feb 19, 2008  at  02:39 AM
Nettie, something similar to yours - stand in a doorway, with your arms at your sides naturally. Move your hands sideways (ie, lift your arms up, but don't bend them) until they touch the door frame either side of you and keep on applying pressure for at least 30 seconds. Move away from the doorway, and try to keep your arms down!
Posted by Smerk  on  Tue Feb 19, 2008  at  03:02 AM
The nose illusion may work better if you try it with a pen. Cross your fingers with as much overlap as you can muster and slide the pen up and down the "v" that your fingertips make.

The further to the "outside" of your fingers you can contact the pen with, the more convincing the illusion. The pads of your fingers don't work so well.
Posted by xzzy  on  Tue Feb 19, 2008  at  08:53 AM
This is kinda hard to explain, but I'll do my best... If you hold your hands out in front of you, cross hands and intertwine fingers, palm to palm, and then fold your hands down and toward you, so that the intertwined fingers rise to your face... got it? (This is best done to another person, because once you get used to it, it's easier.) Now, when any finger on your mixed hands is pointed to (without being touched), it will be difficult to move that chosen finger, cuz it's upside down and backwards... I warned you it was confusing, but it works. Word of caution: resist the temptation to pull downward on your subject's folded hands... it hurts, and is probably a favorite game at Gitmo. You're welcome
Posted by Hairy Houdini  on  Tue Feb 19, 2008  at  04:52 PM
I didn't feel two noses but when I looked down I saw two fingers, crossed, on the tip of my nose...

I think I'm insensitive, the others didn't work for me either.
Posted by Jean  on  Thu Feb 21, 2008  at  12:25 PM
The crossed fingers work really well with a marble. Cross your fingers and roll a marble around on a tabletop. Aces!
Posted by Karlos T. Jackal  on  Mon Feb 25, 2008  at  04:04 AM
omg oh em gee
the cross ur fingers touch ur nose thing really worked 4 me is waz really crazy but fun
Posted by mella  on  Mon Apr 07, 2008  at  05:11 PM
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