My 7 year old daughter was tickling her sister and then she asked me why when she tickles herself she shouldn’t laugh. We have tried it all at home and indeed if you tickle yourself, you don’t laugh.
Answer
The response to tickling is controlled by the cerebellum. The big difference between tickling oneself and being tickled by another lies in the predictability of stimulating sensitive skin parts. When you tickle yourself, you have full control over the timing of the stimulation. The cerebrum can thus pass on the signal to the cerebellum that a stimulus will be given.
Not so in case someone else tickles you. However much you expect it, you will never be able to estimate exactly where and when you will be stimulated. The cerebellum is therefore not prepared and involuntary movements and a tendency to laugh arise.
Answered by
Dr. Pieter Hindryckx
gastroenterology
http://www.ugent.be
.