Sensitivity to itching is a sensation of its own – research proves it

In addition, people seem to sense tickling in the same places on the body, regardless of culture.

Areas that itch particularly easily are the armpits, sides and soles of the feet.

Dutch Researchers at Radboud University asked 448 Chinese, Dutch and Greek young adults which parts of their body were easiest to tickle.

The participants first marked the easily itchy spots on the digital human figures. They also marked the points where they experience other touch, pain and pleasure.

In this way, the researchers were able to compare the placement of different sensations in the body.

The itchiness somewhat resembled ordinary touch sensitivity, but still had its own recognizable bodily pattern.

According to the researchers, itching does not seem to be just a particularly strong sensitivity to touch – or, for example, a form of pain or pleasure.

Best sensitivity to tickling was predicted by how little the body part was usually touched.

According to the researchers, the sensitivity of rarely touched areas may be related to surprise. When the touch is not used to, it can be harder to anticipate and the reaction can therefore be stronger.

The phenomenon may also be self-reinforcing. An area that itches easily, such as the armpit or the soles of the feet, is touched less precisely because it is known that touching that area of ​​the body causes itching.

A good example of this phenomenon is hands. They are very sensitive to touch and are constantly touched, but they are not the most itchy parts of the body. The less frequently touched armpits, on the other hand, are particularly sensitive to touch.

Perception supported by a naturalist Charles Darwin the idea presented already in the 19th century, according to which the sensitivity to tickling is affected by how accustomed a part of the body is to touch in general.

Other explanations tested in the study, such as the thinness of the skin or the density of sensory nerves, did not alone explain sensitivity to tickling.

However, the researchers emphasize that the study does not show that a slight touch increases the sensitivity to tickling. The effect of anticipation of surprise and touch should be investigated in laboratory experiments.

Research at the same time raises the old question: what purpose does sensitivity to tickling serve?

It is still not known. The similarity of response to tickling in different cultures and in humans and great apes suggests that the phenomenon has its roots in the evolution of the species.

Tickling can be related to, for example, play and strengthening social bonds, but its actual function was not resolved by recent research.

The study looked at intense, laughter-inducing tickling. On the other hand, the sensation of itching caused by a light touch of the skin was not studied.

The study was published Nature Human Behaviour in the journal.