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

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.

Partial memory reinstatement while (lucid) dreaming to change the dream environment

“…Upon completion of the task while dreaming, polysomnography shows both the systematic eye movements and global patterns consistent with a sleeping brain (see Baird et al, 2019 for review). Armed with the ability to control (i.e., experimentally manipulate) dream content, researchers have asked participants to complete a variety of tasks during their lucid dreams to better understand the dreaming brain (Erlacher & Schredl, 2008b), ranging from clenching fists (Dresler et al, 2011;Erlacher et al, 2003) to exercising (Erlacher & Schredl, 2008a), and even tickling themselves (Windt et al, 2014). These works suggest that the dream body is under explicit control during lucid control dreams, but what of the dream environment itself?…”

Prosthesis embodiment and attenuation of prosthetic touch in upper limb amputees – A proof-of-concept study

“…The mean value of these three items served as dependent variable (i.e., the sensory score measure) for each condition. This measure has repeatedly been used before in the study of sensory attenuation (e.g., Blagrove, Blakemore, & Thayer, 2006;Windt, Harkness, & Lenggenhager, 2014).…”

Understanding, Explanation, and Active Inference

“…While this ensures the agent remains-for all practical purposes-fixed to the spot, it also liberates [or detaches (Gärdenfors, 2005;Pezzulo and Castelfranchi, 2007)] the inference process from the constraints of sensory input. As such, it can be seen as a form of sensory attenuation of the sort we might anticipate during dreaming (Windt et al, 2014), imagination (Villena-González et al, 2016;Kilteni et al, 2018), or episodic recall (Conway, 2001;Barron et al, 2020). This accounts for the role of the likelihood.…”