Olfactory dreams—smelling in dreams—are uncommon but real, brief, and emotionally charged, resembling everyday odors. People who report such dreams are better at identifying real odors, an effect not explained by motivation or attention. The findings suggest that olfactory imagery exists but its occurrence depends on the strength of connections between olfactory and semantic memory, which are typically weak in olfaction.
Visual experience contains more information than can later be recalled, and this study tested whether the same distinction exists for smell. In two experiments, participants rated odor features (e.g., how banana-like) both while smelling and after the odor was removed. On some trials the ratings matched; on others they differed. Each odor was presented twice: for half the odors both trials were identical, for the rest one trial differed. The after-smelling rating was always the same for each odor, allowing reliability to be measured. Incongruent profiles were least reliable. Attempting to access specific odor features after the odor is gone is harder if those features were not attended during smelling, suggesting more information is available during smelling than can be accessed afterward.
People who regularly ingest very small amounts of psychedelic substances (microdosing) report minimal acute effects but claim long-term health and wellbeing benefits. In an observational study, 98 microdosers provided daily ratings of psychological functioning over six weeks; 63 also completed psychometric measures at baseline and study end. Daily ratings showed a general increase in reported psychological functioning on dosing days but limited evidence of residual effects. Pre- and post-study measures revealed reductions in depression and stress, lower distractibility, increased absorption, and increased neuroticism. A second study of 263 naïve and experienced microdosers found that participants believed microdosing would have large, wide-ranging benefits, contrasting with the limited outcomes reported by actual microdosers.