Tickling

Tickling is the act of touching a part of the body lightly so as to cause involuntary laughter or twitching movements.

Origins

The word evolved from the Middle English tikelen, perhaps frequentative of ticken, to touch lightly. The sensation of surprise elicited by tickling protects against crawling animals and insects, such as spiders, mosquitos, scorpions or beetles, which may be why it evolved in many animals, including rats. Some evidence suggests that laughing is a nervous reaction that can be triggered by tickling; indeed, very ticklish people often start laughing before actually being tickled.

It is also unknown why certain areas of the body are more ticklish than others, and it varies for different people. Many people find that their ribs are the most ticklish, while others find the soles of their feet to be the most ticklish. Other commonly ticklish areas include the armpits, toes, sides, stomach, and other sensitive areas.

Society

Tickling is almost certainly a form of social interaction. One feature of tickling is that we do not laugh when we tickle ourselves, only when other people tickle us. This implies that the brain may have a different mechanism for responding to the two types of tickling. Charles Darwin theorised on the link between tickling and social relations, arguing that tickling provokes laughter through the anticipation of pleasure. If a stranger tickles a child without any preliminaries, catching the child by surprise, the likely result will be not laughter but withdrawal and displeasure. Darwin also noticed that for tickling to be effective, you must not know the precise point of stimulation in advance, and reasoned that this is why you cannot effectively tickle yourself.

Tickling is defined by many child physiologists as an integral bonding activity between parents and children. In the parent-child concept, tickling establishes at an early age the pleasure associated with being touched by a parent with a trust-bond developed so that parents may touch a child, in a unpleasant way, should cirumstances develop such as the need to treat a painful injury or prevent harm from danger. This tickling relationship continues throughout childhood and often into early to mid-adolescence.

Another tickling social relationship is that which forms between siblings of relatively the same age. Many case studies have indicated that siblings often use tickling as an alternative to outright violence when attempting to either punish or intimidate a sibling. The sibling tickling relationship is the most common which develops into an anti-social situation, whereas one sibling will tickle without mercy the other to such ends as helpless laughter.

In general society terms, the idiom tickled pink means to be pleased or delighted.

Torture

The act of tickling has also been known as a method of torture, in that subjecting an extremely ticklish person to prolonged tickling can, in the end, be very painful for the victim. The first recorded use of tickle torture was during the Roman Empire when a method known as "goat licking" was employed as criminal punishment. Goat licking involoved covering a victim's feet with salt, or other sweet substance, and having a goat lick the soles raw usually resulting in painful blisters.

The Chinese are perhaps the best known for using tickling as torture, however most legends of Chinese tickle torture are surrounded by myth. The Chinese saw tickle torture as a perfect punishment for nobility, in that the torture left no marks and the victim could recover relatively quickly. What few records that exist today, regarding Chinese tickle torture, often speak of persons restrained with bare soles exposed to professional torturers who would tickle the feet for hours on end.

Tickling as torture survived into the Middle Ages and Colonial American times, but to the lesser degree of being used as public humiliation. The stocks were a device which were specifically designed to restrain a victim's bare feet, thus allowing passersby to tickle torture the soles.

The stocks have also survived into the modern age, with some countries using devices for more painful tortures such as burning the feet with fire and electricity. Stocks can also be found in the realm of public entertainment, such as displays available at Renaissance Faires.

Fetishism

Tickling as a fetish is perhaps one of the most common human behaviors known, in that studies indicate nearly 85 percent of adults in some way or another enjoy tickling others, being tickled themselves, or watching others be tickled.

Apart from these general attitudes from tickling, forced laughter by tickling can also be found in the sexual fetish world of BDSM. Those who gain sexual pleasure from tickling and/or being tickled are known to have a Tickle Fetish. Those who seek tickling out, and who gain pleasurable excitement from tickling and/or being tickled are known to have a "Tickling Fixation". Tickle fetishes involving "erotic tickling" (frequent breaks, safe words, sensual movements), using fingers or items such as feathers and brushes to produce tickling sensations as part of erotic foreplay.

Research

Researcher Sarah-Jayne Blakemore confirmed Darwin's propositions by investigating how the brain distinguishes between sensations we create for ourselves and sensations others create for us. Blackmore used robotic arms to tickle people and found them to be as effective as real people in provoking laughter. When her subjects used a joystick to control the tickling robot, however, they could not make themselves laugh. This suggests that when a person tries to tickle him- or herself, the cerebellum sends to the somatosensory cortex precise information on the position of the tickling target and therefore what sensation to expect. Apparently some cortical mechanism then decreases or inhibits the tickling sensation.

Washoe, a chimpanzee who learned to use the American Sign Language, has been reported to frequently make the sign for "tickle me" to researchers, similar to children who enjoy being tickled.

Fiction

In some science fiction literature, devices known as tickling boots are depicted as punishment-torture devices employed by some technological societies. Also in a comic book from the 60's "Magnus: Robot Fighter" there is one instance of a weather control tower producing "Tickle Rain". People hid under transparent plastic domes that had handles on the inside, so that the first people who managed to get under the domes could hold the domes down from the inside and then watch the "unfortunate" others being tickled to helpless hysterics by the rain drops.

Other references

Blakemore S-J, DM Wolpert & CD Frith (1998). Central cancellation of self-produced tickle sensation. Nature Neuroscience 1, 635-640.

Carlsson K, P Petrovic, S Skar, KM Petersson & M Ingvar (2000). Neural processing in anticipation of a sensory stimulus. Journal of Cognitive Neuroscience 12, 691-703.

Berk, L.S., Tan, S.A., Fry, W.F., Napier, B.J., Lee, J.W., Hubbard, R.W., Lewis, J.E. and Eby, W.C. Neuroendocrine and stress hormone changes during mirthful laughter. Am. J. Med. Sci., 298:390-396, 1989.

Boiten, F. Autonomic response patterns during voluntary facial action. Psychophysiol., 33:123-131, 1996.

Ekman, P., Levenson, R.W. and Friesen, W.V. Autonomic nervous system activity distinguishes among emotions. Science, 221:1208-1210, 1983.

Fried, I., Wilson, C.L., MacDonald, K.A. and Behnke, E.J. Electric current stimulates laughter. Nature, 391:650, 1998.

Fry Jr., W.F. The physiologic effects of humor, mirth, and laughter. JAMA, 267:1857-1858, 1992.

Yoon, C.K. Don't make me laugh: scientists tackle tickling. J. NIH Research, 9:34-35, 1997.

• Michael Moran, Erotic Tickling, Greenery Press, 2003. ISBN 1890159468.

External links

• Website detailing why people cannot tickle themselves
• Telegraph (UK) Article on "robot tickling experiment"
• Boston Globe Online - Why are some people not ticklish?
• Article on being tickled to death from The Straight Dope.