Scientists have identified consistent ticklish "hotspots" across the human body that are recognized universally, according to a study published in Nature Human Behaviour. Researchers from Radboud University in the Netherlands utilized machine learning techniques to create a detailed map of ticklishness, finding that areas such as the neck, armpits, abdomen, and soles of the feet elicit similar responses across diverse cultural groups, including Chinese, Dutch, and Greek participants.
Across nearly 450 participants, 71 percent reported being moderately to very ticklish, with laughter being the most common reaction. The study indicated that these commonly ticklish areas are not typically touched during everyday interactions, which may contribute to a heightened surprise response when tickled there. This suggests ticklishness may be distinct from ordinary touch or pain and could play a role in social interactions.
When tickling is initiated by a romantic partner, the groin and inner thigh areas also become ticklish hotspots, the study found. The patterns observed in human ticklishness closely mirror those seen in great apes, our closest living relatives, who also exhibit similar tickling behaviors involving laughter and targeting the same body areas. This similarity suggests that tickling may be an evolutionarily rooted trait shared across hominids.
Previous research has also explored the nature of ticklish laughter. A 2024 study found that human laughter induced by tickling is acoustically distinct from laughter resulting from jokes or other humorous stimuli. An analysis of YouTube clips indicated that ticklish laughter often exhibits less vocal control and is perceived as more involuntary. These findings collectively suggest that tickling is an ancient play behavior with a biological basis.
The precise function of tickling, however, remains an area for further investigation. The current study's findings, however, provide a clearer understanding of where and why humans experience this unique sensation across different cultures.