Causes of Ticklishness
Ticklishness is a human response to physical stimuli created by the perception of the brain. There are actually two types of ticklishness. Ticklishness can be defined, scientifically, as knismesis and gargalesis. Knismesis is a ticklish response to a very slight touch. A feather applied to the sole of the foot will create ticklishness. While stronger pressure with a piece of wood might illicit no reaction. It seems paradoxical that a light touch can create a greater response than a heavy touch. Gargalesis is heavy pressure applied to ticklish spots of the body such as under the arms or on the ribs. This form of ticklishness may be unpleasant at first, but creates laughter and smiling (Harris, Christine R., 1999).
A study was done in the University of Illinois where three thousand participants were asked about the sensation of laughter and tickling. These participants described the feeling as things such as "I must laugh. I'm compelled, forced to do it to relieve a strain," "must laugh or burst," "am excited and know something must happen," "a creepy feeling inside spreading over the whole body,". One could assume from these descriptions that laughter and ticklishness is an involuntary compulsion to stimuli (Hall, G., & Allin, A., 1897). Ticklishness is involuntary; strangely it is even possible to tickle yourself. The areas of ticklishness are universal in most people. (Hmar, R., 2015). As found by the University of Illinois study “most ticklishness shows the following in order of frequency: soles of the feet, under the arm, neck and throat, ribs, back, under the chin, stomach, knees, at sight of pointed finger, cheeks, palm, upper lip, nose...”. Ticklishness can be created in some children by merely pointing a finger and making a buzzing noise (Hall, G., & Allin, A., 1897). It is possible to avoid feeling ticklishness by placing your hand on the tickler's face and telling yourself that you are the tickler, you may not feel ticklish. This is because ticklishness is a perception by the biological systems of the body.
There are many biological reasons for ticklishness. There are some animals that flinch and twitch to the reaction of bugs and parasites trying to invade their bodies. A horse will naturally twitch to defend against bot flies to avoid being infected with parasites (Hall, G., & Allin, A., 1897). Knismesis ticklishness in humans may be a natural defense against similar parasites such as ticks or leeches. The humans that were not ticklishness may have died out from parasites. If a very small poisonous spider were to crawl down a person's back they would be tickled and flinch the spider off. The skin has such sensitive small hairs they can detect the movement of very small creatures that could be a threat to survival. The tiny hairs and nerves on the skin send signals to the central nervous system directly to the brain. In the brain two systems work together. These are the somatosensory cortex and the anterios cingulated cortex. The somatosensory cortex analyzes all touch perception and pressure points then realizes what each touch means to illicit a response from stimuli. The anterios cingulated cortex is the center that decides if the touch stimulus is pleasurable and regulates laughter (Hmar, R., 2015). There are social reasons for the laughter involved in ticklishness as well.
Forced gargalesis tickling was used as a form of torture in ancient Japan. A person was strapped to a chair and goats were allowed to lick the prisoner's salted feet (Schreiber, M., 2001). This form of torture may have been used in many other countries all around the world; such may very well be historically a universal human form of punishment. It is particularly strange because of the behavioral reasons humans tickle one another. The most common reason a human will tickle another human is to build positive relationships as a form of communication and bonding. Tickling is an incredibly social interaction between humans. Humans are 30 times more likely to laugh when tickled in the presence of large groups than alone with the tickler. (Buchen, L., 2009)
Mothers will often gargalesis tickle a child to build a mother/child bond and may be a determining reason the child will have positive bonds with other humans in the future. Charles Darwin believed in this theory, and he wrote an entire book on the social bonds made through tickling and laughter (Darwin, C., 1965). A teenager is seven times more likely to feel ticklish by the touch of the opposite sex. Lovers will often knismesis tickle each other as a playful form of affection (Hmar, R, 2015). The gargalesis tickling learned as a baby might be the result of knismesis tickling in a romantic relationship in the future. This affection may partially be a reason that sexual relationships form and reproduction occurs. Ticklishness could be a determining social factor that propagates the species. Men on average are more likely to be ticklish due to less physical contact from the opposite sex. Males tend to be less familiar with knismesis touching that result in a ticklishness reaction. Due to possessing more dominate behaviors than females, men are more likely to touch women than women are to touch men.Humans are also not the only species that does this. Primates and rats will gargalesis tickle each other to build socialization (Hmar, R, 2015). Chimps will tickle each other as a rough-housing and play activity in youth, and sometimes into adulthood. This is a socialization exercise to learn to protect themselves through play fighting. (Harris, Christine R., 1999). Dogs and other non-primate animals use play fighting to build socialization and learn self-defense, but only primates and rats appears to tickle one another (Goldman, J., 2013). This can be seen in humans as well. In households that have many children or the school yards of elementary schools, humans play fight and tickle each other in a similar way that chimps do. The ticklish socialization of primates builds clues to the evolutionary reason from ticklishness.
Although, Knismesis ticklishness is strictly a human behavioral response. Gargalesis ticklishness and ticklish laughter is not restricted to human. Orangutans, chimpanzees, gorillas, and bonobos show they can be gargalesis tickled as well. At the University of Portsmouth in the United Kingdom a study was done to examine primate laughter when tickled. It was found that the relationship of laughter response was similar to the relationship to the species similar in evolutionary genetics. (Cell Press, 2009). There is scientific proof that gargalesis ticklishness has been passed down through genetics and evolution. If the apes that share a similar ancestor to us are ticklish, it would be a good assumption that humans have always been ticklish and possibly the species of sub-humans we evolved from were ticklish too. Studies into ticklishness of primates have also proven other evolutionary realities. Humans laugh with we exhale. Chimpanzees can laugh with exhale and inhale. Humans use a more regular voicing when they laugh than primates (Cell Press, 2009). Science has added more evidence that humans did not evolve from apes or chimps from these differences in ticklishness. The only answer is that we evolved from a common ancestor that laughed differently.
In conclusion, ticklishness has many causes and exists for many reasons. Ticklishness is not a meaningless action. It is a defense mechanism to protect us from parasites and microscopic invaders. Ticklishness is important for the propagation of the human species. It develops social bonds. If we do not build these bonds, we possibly would not reproduce and cease to exist as a species. If humans were not ticklish we would not uniquely define ourselves as a different species from our distant ancestors. Humanity’s unique form of ticklishness and ticklish laughter scientifically proves evolution from distant the relatives of currently existing primates. Please continue to tickle you children and lovers, for the health and continuity of humanity as a whole.
Buchen, L. (2009). Human Laughter Echoes Chimp Chuckles. Wired Magazine. Retrieved from http://www.wired.com/2009/06/evolutionlaughter/
Cell Press. (2009, June 5). Ticklish Apes? Young Apes Hoot Holler And Laugh In Way Similar To Human Infants. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2009/06/090604124013.htm
Darwin, C. (1965). The expression of the emotions in man and animals. Chicago: University of Chicago Press.
Goldman, J. (2013, January 9). Why do animals like to play? British Broadcasting Channel. Retrieved from http://www.bbc.com/future/story/20130109-why-do-animals-like-to-play
Hall, G., & Allin, A. (1897). The Psychology of Tickling, Laughing, and the Comic. The American Journal of Psychology,9(1), 41-41.
Harris, Christine R. (1999): The mystery of ticklish laughter. American Scientist, July–August v87 i4 p344(8).
Hmar, R. (2015, January 27). Why Does Tickling Make You Laugh? India Times. Retrieved from
Schreiber, M. (2001). The dark side: Infamous Japanese crimes and criminals. Tōkyō: Kōdansha Intānashonaru.