Why Can't We Tickle Ourselves?

Abstract

When we tickle ourselves something prevents the sensation being as strong as when someone else does it. It is suggested that the ‘something’ may be: (i) the predictability of the stimulus; (ii) the presence of feedback from the movement of the arm doing the tickling; (iii) the presence of a corollary discharge from the voluntary movement of the tickling arm; (iv) the absence of a social/sexual context. To study these, Ss rated perceived ‘tickle-strength’ in situations where they were tickled: (a) with their eyes closed; (b) with their eyes open; (c) with their own arm doing the tickling, but being moved by someone else; (d) by themselves. One group of Ss was divided into same sex and different sex subject-experimenter pairs. The results showed significant effects of predictability and sensorimotor feedback.