Not everyone reacts to tickling in the same way. Although involuntary laughter can create a feeling of exhilaration in some people (Ruch, 1993), it may also induce terror in others, even though the intensity of touch is the same in both cases.
The essential duality of tickling is that it shares elements of both pleasure and pain, and the tension between both elements affects stress levels within the body.
Tickling Causes Physiological Changes in the Body
Newman et al. (1993) demonstrated how people can be conditioned to feel ticklish even before they are even touched. The anticipation of being tickled triggers a series of physical reactions in the body, such as evasive spasms in the soon-to-be tickled area, dilation of the pupils, rapid breathing, and an increase in blood pressure.
Once tickling begins, the body undergoes additional physiological changes, including:
- elevation of the heart rate to greater than 120 beats per minute;
- irregular respiration patterns, sometimes accompanied by hiccups or coughing;
- relaxing of smooth muscle cells, which cause widening of blood vessels (vasodilation) and increases in blood flow through the peripheral arteries; and
- increased muscle activity, especially in the diaphragm, the face, and along the arms and legs.
For people who enjoy tickling, however, physical excitement may give way to profound relaxation and emotional release as the tickling begins and continues.
This suggests that tickling is as much a matter of perception as well as of physiology. Even though involuntary laughter results in both cases, the level of stress evoked in the body is quite different.
How Does the Body React to Stress or Relaxation?
When the body is subjected to stress, cortisol (a corticosteroid hormone) production increases. Cortisol is often called the 'stress hormone' because it interferes with the immune system, causes blood sugar levels to rise, and elevates blood pressure. Stress also elevates levels of epinephrine, which is known to be an immunosuppressant.
When the body is in a state of relaxation, however, opiate-like polypeptide compounds known as endorphins are released. Endorphins relieve pain and increase feelings of well-being. Other researchers have noted how laughter increases the activity of certain white blood cells (i.e., lymphocytes). These lymphocytes have the ability to attack and kill harmful tumor cells in a process called spontaneous lymphocyte blastogenesis.
Does Ticklish Laughter Reduce, or Cause Stress?
As Harris (1999) observed, the experience of being tickled “incorporates both pleasant and unpleasant sensations,” and people react to the part they enjoy (or dread) the most. For people who enjoy being tickled, pleasure outweighs stress. Tickle-induced laughter reduces cortisol production and increases endorphin levels. Tickling increases blood flow through the circulatory system, thereby making the heart stronger. Tickling also enhances the immune system and stimulates nerves throughout the nervous system, creating a pleasant tingling sensation that persists after the tickling stops.
The effect is entirely the opposite in people who dislike being tickled. Although involuntary laughter should produce the same benefits, fear takes precedence over pleasure. Endorphin levels decrease as panic suppresses any sensation of enjoyment. Worries over loss of control may cause cortisol production to jump. Laughter is mixed with tears of agony, which quickly turn into feelings of anger once the tickling stops and the victim escapes.
Pteronophobia, or the Fear of Tickling
For about 15% of the population, tickling becomes less fun the longer it occurs. People who dislike being tickled may develop a tickling phobia. The fear of being tickled by feathers even has a medical name: pteronophobia.
Harris (1999) noted how “Medieval warriors sometimes tortured victims to death using nothing but unrelenting tickling.” Prolonged laughter may provoke seizures, loss of consciousness, blood clots, heart attacks, and even suffocation. Thus, the dislike of uncontrolled tickling does have a sound basis in science.
The Need for Laughter
People who dislike tickling, however, may have social anxiety and share a corresponding fear of touch or intimate contact. As self-tickling is not possible, tickling becomes a form of social communication (Provine, 2002). In surveys conducted at the University of Maryland, Professor Provine noted, “that people tickle and are tickled by friends, family, and lovers, and that the rationale given most often for tickling someone was to show affection.”
Children seek out tickling as a form of play, which then evolves into sex play during puberty and beyond. As Provine noted, adolescents and adults “are overwhelmingly likely to tickle and be tickled by someone of the opposite sex.”
The psychology of tickling is complex because tickling is difficult to research. Laboratory experiments cannot duplicate true natural tickling (gargalesis), and so conclusions are reached from lighter tickling (knismesis) touches under brief artificial conditions.
References
Harris CR. 1999. The Mystery of Ticklish Laughter. American Scientist. 87:344-51.
Provine RR. 2002. Ha! Ha! Ha! — What’s Funny? Why Do We Laugh? NZZ Folio.
Ruch W. 1993. Chapter 42. Exhilaration and Humor. In: M Lewis & JM Haviland, eds. The Handbook of Emotions. New York: Guilford Publications. pp. 605-16.
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