Why doesn't it tickle when you tickle yourself?

It's because you can expect it and you know what it's going to feel like and when its happening, but if somebody else is doing it to you, you don't know when or how it will happen.

This is actually one of the biggest mysteries of neuroscience. It has something to do with proprioception - the awareness of where the various parts of your body are in space.

If you think about it it makes sense. You don't want to be surprising yourself every time you touch yourself, it would drive you crazy. What seems to happen is that the motor cortex, the part of your brain that controls what your hands are doing, sends a signal to the part of your brain that normally reacts to an unexpected touch (which could be a threat), telling it to temporarily switch off your defence mechanism so you are not startled by the touch when it comes.

It's even more complicated than that because there is a context effect as well. Being tickled by one person can be delightful but the same tickle from a different person can be repulsive; the emotional part of the sensation depends how you feel about the person doing the tickling.

Touch is a really exciting field of research at the moment. We know so little about it compared to the other senses.

You are not tickling yourself right :l

It could be that because you are expecting it or because you know you are going to tickle yourself, the mind just pretend it is not ticklish.

because maybe if you tickle your self your little hairs only react to other peoples fingers .