Virtual reality training of lucid dreaming

Abstract

Metacognitive reflections on one's current state of mind are largely absent during dreaming. Lucid dreaming as the exception to this rule is a rare phenomenon; however, its occurrence can be facilitated through cognitive training. A central idea of respective training strategies is to regularly question one's phenomenal experience: is the currently experienced world real, or just a dream? Here, we tested if such lucid dreaming training can be enhanced with dream-like virtual reality (VR): over the course of four weeks, volunteers underwent lucid dreaming training in VR scenarios comprising dream-like elements, classical lucid dreaming training or no training. We found that VR-assisted training led to significantly stronger increases in lucid dreaming compared to the no-training condition. Eye signal-verified lucid dreams during polysomnography supported behavioural results. We discuss the potential mechanisms underlying these findings, in particular the role of synthetic dream-like experiences, incorporation of VR content in dream imagery serving as memory cues, and extended dissociative effects of VR session on subsequent experiences that might amplify lucid dreaming training during wakefulness. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Keywords: REM sleep; consciousness; dissociation; lucid dreaming; metacognition; virtual reality.

Figure 1.

(a) Study design. After a baseline week including questionnaires and one night of polysomnography, participants were pseudo-randomized into one of three conditions. The experimental group followed a VR-enhanced training of lucid dreaming for four weeks, the active control group followed a simple lucid dreaming training for four weeks, whereas the passive control group received no training. In the sixth week, participants received three polysomnographies each in addition to questionnaires. Dream lucidity was measured each morning with the DLQ; after each polysomography with the LuCiD; and during nights with polysomnographies via eye signalling as verified by the EOG. (b,c) Screenshots of the custom-made VR training scenario ‘Spinoza Café'. (Online version in colour.)

Figure 2.

Average lucidity as measured by the DLQ (a) or LuCiD (b) post-training (final week), compared to individual baseline (first week). (c) Dream lucidity as measured by the DLQ over 42 days for all 39 participants, separated by group. Trend lines fitted to each time series using linear regression. (d) Successful eye signal-verified lucid dreaming in the final week by a participant from the VR group. (Online version in colour.)