Effects of attention and expectation on tickle sensation.

The purpose of the present study was to examine the changes of the tickle sensation reflected in effects of the direction of attention to one's own body (Exp. 1) and the expectation of the experimenter's gestures (Exp. 2). In Exp. 1, for 15 subjects, when tickled on their own foot soles, the tickle sensation was not significantly changed by attending to the stimulus and to one's own sole. These results suggested the importance of instructions. In Exp. 2, 6 subjects were tickled and were required to report their experience while they looked at the experimenter's gestures and were tickled. Although the subjects' stimulations were unaffected by looking at the gestures, the tactual stimulus elicited a tickle sensation. From these results, quantitative and qualitative differences in subjects' tickle sensation may be identified.