Why are we tickhlish? New research maps a familiar human sensation
Most people know what it feels like to be tickled, yet scientists still do not fully understand why some parts of the body are more ticklish than others. A new study from Karolinska Institutet and Radboud University shows that ticklishness follows a remarkably similar pattern across cultures and appears to be shaped by more than simple touch sensitivity.
To investigate ticklishness, Konstantina Kilteni and Ziliang Xiong studied 448 young adults aged 18-30 from Chinese, Dutch and Greek cultural backgrounds. The participants answered questions about their experiences of tickling and mapped the parts of their bodies where they feel most ticklish. The participants also mapped touch sensitivity, pain, pleasure, self-touch and social touch, allowing the researchers to investigate whether ticklishness has a distinctive bodily pattern of its own.
Striking similarities between groups
The results showed striking similarities between the three groups. Nearly all participants reported having been tickled at least once, and the body regions most often identified as ticklish were the neck, armpits, abdomen and soles of the feet. These patterns were consistent across cultures and even across individuals.
“What surprised us was not simply that the same areas were ticklish, but how strongly this bodily pattern generalized across cultures and even across individuals. This suggests that there is a recognizable bodily organisation to ticklishness”, says corresponding author Konstantina Kilteni, assistant professor and principal investigator at the Department of Neuroscience and at Radboud Universiteit, Donders Institute for Brain, Cognition and Behaviour.
When tickling involved an intimate partner, the pattern was similar but additionally included the groin and inner thighs. Crucially, these bodily patterns were highly consistent across the Chinese, Dutch and Greek groups.
Ticklishness has its own bodily pattern
The researchers compared maps of ticklishness with maps of touch sensitivity, pain, pleasure and other bodily sensations. Although there was some overlap, machine-learning analyses showed that ticklishness has its own distinctive bodily pattern and can be reliably distinguished from other sensory experiences.
The study also tested several theories that have been proposed to explain why certain body regions are especially ticklish. The strongest support was found for an idea first suggested by Charles Darwin: areas that are touched less often tend to be more ticklish. However, this factor alone could not explain the entire pattern. Instead, the findings suggest that ticklishness arises from a combination of sensory, physiological and social factors.
An evolutionary connection?
The similarities did not stop at cultural boundaries. Intriguingly, some of the patterns observed in humans resemble reports of tickling in other great apes.
Great apes have been observed using their hands (or mouth) to tickle many of the same regions identified in the human body maps and responding with laughter-like vocalizations. Tickling also tends to occur between socially bonded individuals. In bonobos, for example, strongly bonded pairs such as mothers and infants tickle each other more than weakly bonded pairs. These parallels raise the possibility that ticklishness is not simply something unique to humans.
“We still do not know its precise function, but these similarities are consistent with the idea that ticklishness is an evolutionarily conserved trait,” says Konstantina Kilteni.
Publication
Human ticklishness is a widespread, culturally shared and bodily organized sensory experience
Ziliang Xiong, Konstantina Kilteni, Nature Human Behaviour (2026), https://doi.org/10.1038/s41562-026-02535-z