Why We Tickle: Global Study Reveals Universal Sensitivities

The question of why humans are ticklish, particularly in areas like the stomach, armpits, and feet, remains an enduring mystery that has puzzled philosophers and scientists for centuries. A recent study, however, sheds new light on this common human experience, revealing its widespread nature across cultures.

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Tickling and being ticklish appears to be a very widespread experience that we share across cultures.

Konstantina Kilteni, a researcher at Radboud University in the Netherlands and the Karolinska Institute in Stockholm, noted that "tickling and being ticklish appears to be a very widespread experience that we share across cultures." This observation, coupled with the fact that many prominent thinkers like Darwin, Socrates, and Aristotle were intrigued by ticklishness, prompted Kilteni and her colleagues to investigate the phenomenon more deeply.

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Many great philosophers and scientists have discussed it. Darwin, Socrates, Aristotle, Galileo Galilei and Francis Bacon were all interested in the function of ticklishness.

Their research aimed to confirm the prevalence of ticklishness and explore whether cultural norms influence where on the body people are most sensitive. The study involved 448 men and women aged 18 to 30 from Dutch, Chinese, and Greek backgrounds. The findings, published in Nature Human Behaviour, indicated remarkable consistency among the groups.

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We wanted to understand the most fundamental thing. Is the behavior as widespread as we think? Do cultural norms have anything to do with where on the body we are ticklish?

Participants described tickling with similar language, reported comparable reactions, and exhibited similar dynamics regarding who tickles whom. The study also noted that the behavior evolves from childhood to adulthood. Over 98 percent of participants reported having been tickled, and more than 95 percent admitted to having tickled someone else. Based on these responses, the researchers developed a "ticklishness map" of the body. This map highlights the armpits, stomach, sides, neck, and feet as the most ticklish areas, while the head and palms showed little to no sensitivity.

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The participants described tickling with the same words, they reported the same reactions and the same dynamics about who tickles whom, and also how the behavior changed from childhood to adulthood.