Ticklish problem is solved

A robotic hand on a flexible hose and a scientist under a sheet have proved that tickling makes you laugh because it tickles.

Previous thinking suggested that you would feel more tickled if the action were carried out by somebody you knew rather than a stranger. But psychologists at the University of California at San Diego disproved the idea. They took 34 blindfolded volunteers into a room to be tickled either with the robotic hand or by a person.

In fact, all the tickling was carried out by a scientist hiding under a sheet. To the students it made no difference: they reported feeling equally tickled whichever they were told was doing the stroking. Ticklishness, say the researchers, is a reflex, not an emotional reaction. Charles Arthur