Inducing lucid dreams by olfactory-cued reactivation of reality testing during early-morning sleep: A proof of concept.

The reliable induction of lucid dreams is a challenge in lucid dream research. In a previous study by our research group we were able to induce in about 50% of the participants a lucid dream in a single sleep laboratory night by combining a wake-up-back-to-bed sleep protocol and a mnemonic technique. In the present study, we extended our previous procedure by additional presentation of an odor during sleep to reactivate memory traces about reality testing. In total 16 male participants spent a single night in the sleep lab whereas the procedure induced in two participants a lucid dream (12.5%). The induction rate stays below the success rate of our previous study and therefore odor-cueing seems not a promising technique for inducing lucid dreams. Beside the odor presentation, several other methodological changes have been made, which will be discussed and hopefully help further dream engineering to improve induction techniques.