Synesthesia is associated with distinctive patterns in dream content

Dreams offer insight into how individual differences shape conscious experience in the absence of external input or task demands. This study examines whether synesthesia is linked to distinct patterns in dream content, suggesting underlying differences in cognitive architecture. Leveraging the statistical power of large-scale, naturalistic data, we analyzed 2,337 dream reports from Reddit, comparing 1,169 reports from self-identified synesthetes with 1,168 matched controls. Semantic embedding models and logistic regression achieved modest classification performance, indicating group-level differences in language use. Topic modeling revealed four themes-digital, interpersonal regret, diverse worlds, and violent conflict-that were significantly more prevalent in synesthete dreams. These results suggest that trait-level cognitive organization, as expressed in synesthetic perception, extends across states of consciousness and shapes the thematic content of dreams. The findings support theoretical accounts of dreaming as continuous with waking cognition and demonstrate how stable neurocognitive traits manifest in unstructured, self-generated thought.