Tickle me, I think I might be dreaming! Sensory attenuation, self-other distinction, and predictive processing in lucid dreams.

In ordinary waking life, people cannot tickle themselves because the brain attenuates sensations produced by one's own actions. However, people woken from REM sleep dreams can tickle themselves, and a new web-based study explored whether this also occurs during lucid dreaming. Participants rated sensations during self-tickling and being tickled while awake, imagining, and lucid dreaming. Preliminary results suggest that during lucid control dreams, the usual difference between self-tickling and being tickled by another disappears; both feel similar to self-tickling while awake. The authors speculate that sensory attenuation for self-produced tickles may extend to tickles from dream characters. The study's main contribution is theoretical, using predictive processing to discuss sensory attenuation, self-other distinction, and agency.

Study at a glance

Abstract

The contrast between self- and other-produced tickles, as a special case of sensory attenuation for self-produced actions, has long been a target of empirical research. While in standard wake states it is nearly impossible to tickle oneself, there are interesting exceptions. Notably, participants awakened from REM (rapid eye movement-) sleep dreams are able to tickle themselves. So far, however, the question of whether it is possible to tickle oneself and be tickled by another in the dream state has not been investigated empirically or addressed from a theoretical perspective. Here, we report the results of an explorative web-based study in which participants were asked to rate their sensations during self-tickling and being tickled during wakefulness, imagination, and lucid dreaming. Our results, though highly preliminary, indicate that in the special case of lucid control dreams, the difference between self-tickling and being tickled by another is obliterated, with both self- and other produced tickles receiving similar ratings as self-tickling during wakefulness. This leads us to the speculative conclusion that in lucid control dreams, sensory attenuation for self-produced tickles spreads to those produced by non-self dream characters. These preliminary results provide the backdrop for a more general theoretical and metatheoretical discussion of tickling in lucid dreams in a predictive processing framework. We argue that the primary value of our study lies not so much in our results, which are subject to important limitations, but rather in the fact that they enable a new theoretical perspective on the relationship between sensory attenuation, the self-other distinction and agency, as well as suggest new questions for future research. In particular, the example of tickling during lucid dreaming raises the question of whether sensory attenuation and the self-other distinction can be simulated largely independently of external sensory input.