The kaleidoscope of bizarreness: The analysis of first-person-reports shows the relationship between dreaming and mind wandering to be complex

Spontaneous thoughts and experiences, including mind wandering and dreaming, make up a significant proportion of our conscious mental lives. An influential proposal posits that dreaming and mind wandering exist on a continuum of spontaneous thought, in which dreaming is intensified compared to mind wandering. Yet the precise relationship between dreaming and mind wandering is only beginning to be investigated. Unusual features of dream experience, referred to as bizarreness, are at the heart of theoretical debates about the relationship between dreaming and waking experiences. Traditionally, bizarreness was considered as a distinctive and pervasive feature of dreaming that was absent in waking consciousness, whereas recently, it has been proposed as a dimension along which dreaming is an intensified form of waking mind wandering. Our study is the first to apply an in-depth bizarreness analysis to dreaming and mind wandering reports from the same group of participants within a naturalistic setting. Our results, based on 379 spontaneous reports, suggest that both dreaming and waking mind wandering, have unique bizarreness profiles, involving similarities as well as distinctive differences. Bizarreness is kaleidoscopic in that the comparison between dreaming and mind wandering changes with the precise rating and level of measure (bizarreness type, subtypes, contents) used. This means that dreams cannot, straightforwardly, be described as intensified compared to waking mind wandering on measures of bizarreness, and a more nuanced account, alongside more specific measures, is needed. We propose that our findings can inform and guide future work not just on bizarreness in dreams and mind wandering, but also more broadly on the relationship between conscious experiences in sleep and wakefulness.