Neuroscientists believe tickling to be an important form of pre-verbal communication.
One recent survey found 36 per cent of people actively disliked the sensation of being tickled - and for those who aren't fans it can be frightening and painful - so much so that it was used as a form of torture by Nazi prison guards during World War II.'A phobia of tickling is quite rare - but understandable,' says Dr Sandi Mann, senior psychology lecturer at the University of Central Lancashire.
'Sufferers fear the lack of control that comes from being tickled and the inability to articulate their fear because they are struggling to breathe.
For them the saying 'tickled to death' is a truly scary concept.'Tickle phobias are likely to be triggered by an event in childhood, from a tickling incident to some sort of boisterous horseplay.
Everyone with functioning nerve-endings is susceptible to the sensation of being tickled, but, as irritating as it is for anyone who recalls losing out to a sibling in a tickle-off during childhood, some of us are better at sensing when we are about to be tickled than others, prompting the cerebellum - the part of the brain that predicts the sensory consequences of movements - to block the rest of the brain's response to the tickle.'Simply watching someone else's hand coming towards us isn't enough to predict how it's going to feel.
But if you touch someone's hand as they're about to tickle you it will allow you to block the sensation as if it were your own hand and stop it tickling.'However, the scientists whose findings were published in Consciousness And Cognition discovered that those displaying schizophrenic tendencies - such as erratic behaviour and the inability to derive pleasure from social experiences - are more likely to be able to tickle themselves.
This is believed to be because the process that tells the brain that the act of self-tickling is voluntary is impaired in such people, so they are more likely to react as if the tickle was from an external cause or person.
While some undoubtedly enjoy the sensation of tickling, the action activates a part of the brain that controls facial movement called the Rolandic operculum, making you laugh even if you're not really having good time at all.
Earlier this month, research published in the science journal Consciousness And Cognition revealed that - contrary to experts' previous understanding, that has stood since Greek philosopher Aristotle laid claim to the subject - it is possible for some people to tickle themselves.
Tickling happens when the skin's nerve endings are stimulated, sending a message through the nervous system to two separate regions of the brain: the somatosensory cortex, the area primarily responsible for analysing touch, and the anterior cingulated cortex, an area towards the front of the brain that controls emotion. There are actually two types of tickles: knismesis and gargalesis.
The former is associated with low levels of stimulation to sensitive parts of the body, and can be triggered by a light touch or by a light electric current.'Fortunately, our brains have evolved to block our response to the sensation when we are able to predict what it will feel like - otherwise something as simple as putting on our socks would turn us into a nervous wreck,' says Dr Emily Grossman, an expert in molecular biology The soles of the feet are most people's peak tickle spots because they are filled with highly sensitive nerve receptors.
The armpits - another ticklish area - have numerous veins and arteries that make them extra sensitive.