How does tickling work

Tickling puzzles Sabrinah and she's in good company: Aristotle, Plato, Galileo, and even Charles Darwin all speculated about the paradoxes of tickling. Why don't we laugh when we tickle ourselves, and why do we laugh in anticipation of the tickle The AnswerBank investigates.

Q. Why can't you tickle yourself

A. This question was once raised by Aristotle, who pointed out that laughter is often associated with surprise.

Findings from studies of the brain activity of someone trying to tickle themselves suggests that the part that coordinates movement 'warns' the rest of the brain that tickling is about to happen and so takes away any surprise element. Researchers suggest that the brain is filtering out unimportant self generated movement in favour of much more crucial external stimulation and so is performing an important survival function.

Q. But, why does the mere anticipation of tickling make some people giggle

A. The findings reported in the previous question don't explain why many people start giggling when they know they're about to be tickled. The lack of surprise seems to heighten, not diminish the experience.

Brain scans of people who either were being tickled, or were about to be tickled, showed that there seemed to be no significant difference in the way brains reacted in those two different situations. Scientists believe this apparently unexpected finding is an example of the brain having to prepare itself for action. Most threats of being tickled are actually carried out and so, although you might not be in danger of loosing your life in this case, it makes evolutionary sense for the brain to be in the practice of readying itself for action.

Q. Although people laugh, do we actually enjoy being tickled

A. For most people, tickling is like torture, but the unpleasantness evokes uncontrollable laughter. Prolonged tickling was considered one of the worst forms of torture in medieval times, victims were sometimes tickled to death.

Researchers suggest that laughing in response to tickling worked as an encouragement in pre speech times for members of your group to stimulate your sensitive areas so that you could practise out manoeuvring such life threatening possibilities as a sharp stick in the ribs.

Q. Is there a sex difference in ticklishness

A. Experiments indicate that men are more ticklish than women.

Q. Are any other animals apart from humans ticklish

A. Well, where experiments have investigated the matter, rats and gorillas are ticklish

Are you intrigued as to how something works Just click here to post a question.

by Lisa Cardy