Olfactory dreams: phenomenology, relationship to volitional imagery and odor identification

Phenomenological evidence for olfactory sensation in the absence of appropriate stimulation—imagery—is inconclusive and draws most support from reports of olfactory hallucinations. The current study examined whether more convincing phenomenological evidence could be obtained from normal participants, by studying reports of their olfactory dreams. A questionnaire approach (N = 284) revealed that olfactory dreams were uncommon, had features similar to actual olfaction (emotive and brief), were representative of odors encountered in everyday life, and were positively related to self-report volitional imagery ability. In addition, a sub-group (N = 116) also completed an odor identification test. Participants who experienced olfactory dreams were significantly better at identifying odors, an effect not mediated by motivational or attentional factors. These findings suggest people can experience olfactory images although their occurrence may be governed by the strength of connections between olfactory and semantic memory—notoriously weak in olfaction.