Researchers make a ticklishness body map

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Whether it’s the belly, armpits, or feet, many people are ticklish at least somewhere on their body. Nevertheless, scientists have paid little attention to the silly sensation. As such, two researchers took it upon themselves to investigate the experience, and discovered that it is no laughing matter. 

Ziliang Xiong and Konstantina Kilteni, from the neuroscience department at the Karolinska Institute in Sweden, investigated the experience of getting tickled as well as the distribution of ticklish body parts in Chinese, Dutch, and Greek study participants. 

In their study published in the journal Nature Human Behavior , Xiong and Kilteni tickled 448 adults…just kidding. They studied survey responses from 448 adults. Half of the participants were women, and they were all between the ages of 18 and 30. Seventy-one percent of the surveyed individuals described themselves as moderately to very ticklish, 98.4 percent reported having been tickled at least once, and 95 percent reported that they had tickled someone else. Chinese, Dutch, and Greek participants reported similar reactions—especially laughter—and the neck, armpits, abdomen, and soles of the feet were perhaps unsurprisingly frequently pinpointed as ticklish body parts. 

“Despite differences in cultural background, participants reported remarkably similar experiences of tickling, including its social dynamics, emotional responses, and how they evaluated the experience,” Xiong and Kilteni tell Popular Science. 

They didn’t find this result especially surprising “because tickling is such a common form of playful interaction, especially between parents and children,” they add. “What did surprise us was just how consistent the patterns were across participants with Chinese, Dutch, and Greek cultural backgrounds.”

Based on the survey responses, the team also mapped out a body map of ticklishness, and found that it partly overlaps with bodily areas that others don’t touch as much. While this bolsters a theory Charles Darwin put forth back in 1872 that less touched areas of the body are the most ticklish, the researchers point out that body areas that are particularly more ticklish than others can’t be explained by this one element. 

“Initially, this explanation seemed almost too simple. Our results suggest that it does explain part of the phenomenon, but ticklishness is more complex than this factor alone,” they explain. 

In fact, there is no single theory that completely elucidates these differences, according to the the team. Their research indicates that ticklishness is probably influenced by a mix of physiological and sociopsychological factors. It also suggests that tickling could represent a particular somatosensory experience with distinguishable physiological, neural, and sociopsychological profiles.

Notably, scientists have also observed chimpanzees and bonobos—humans’ closest evolutionary relatives—tickle each other in areas including the armpits, belly, and soles of the feet, and emit laughter-like sounds. 

“This similarity suggests that tickling may have deep evolutionary roots and may serve specific functions that we do not yet fully understand,” Xiong and Kilteni point out. “More research is needed to understand why we are ticklish and what function tickling may serve.”

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Margherita is a trilingual freelance science writer.

Source: Read the original article on www.popsci.com