Scientists from the University of Auckland in New Zealand have created TickleFoot, a gadget that tickles the most sensitive areas of the human foot.

The machine is designed to  the most ticklish areas. It can be used to relieve stress, as it causes uncontrollable laughter, the researchers say. The device is battery operated and can be installed in any ordinary shoe.

It turned out that places susceptible to tickling differ in people depending on gender. In women, this is the center of the foot, and in men, the place is closer to the toes.

To find out where the foot is most ticklish, the authors used magnetic brushes to stimulate various points on the sole of the foot. The team conducted a study involving 13 people: seven women and six men. They rated the level of tickling they felt on a seven-point scale.

For women, the mean was 5.57 and for men, 3.83. There were also slight gender differences in the most sensitive areas on the foot, with women being most ticklish in the center of the arch, and men being most sensitive slightly closer to the toes.

The researchers used this data to 3D print a flexible insole that can be inserted into any regular shoe. The authors called it TickleFoot: it has three tickle drives that stimulate specific points on the sole of the foot. The device is powered by lithium-ion batteries, it lasts for 60 minutes of tickling. TickleFoot can be turned on and off remotely.