Systematic self-observation of entoptics and hypnagogia found that experimental manipulations increased the reported incidence of entoptics but not hypnagogia. The two phenomena appear to be independent, arguing against the entoptic explanation of hypnagogic imagery. The frequency of entoptics follows an inverted U-shaped function of attention level.
Two independent raters scored retrospective dream reports from 179 undergraduate students to test a new rating system for lucid dream content. The weighted Kappa statistic measured chance-corrected interrater agreement. The rating system could reliably identify different types of lucid dream content, though some categories worked less well than others. Revisions to the system are suggested.