5-MeO-DMT sometimes cancels the Ebbinghaus illusion

At a 2026 consciousness-research retreat in Mexico, the writer noticed that 5-MeO-DMT temporarily weakened the Ebbinghaus illusion: two identical orange circles usually look different in size because of their surrounding circles, but under the drug they appeared nearly equal when attention rested between them. Looking directly toward either group restored the usual illusion, and shifting attention produced a smooth, apparently voluntary change. The effect occurred during the comedown after incremental vaporized doses, with the first dose estimated at 3.4 mg. The writer says other retreat participants who noticed a change also saw the illusion weaken; one described deliberately switching between interpretations. Yet a later, higher-dose experience did not reproduce the effect, and the observation was informal and based on self-report.

The experience raises questions about how altered states change visual processing, and whether the effect is specific to 5-MeO-DMT. A cited 2025 study found that psilocybin strengthened the illusion by 38% at 5 mg and 59% at 10 mg compared with placebo, suggesting different psychedelics may affect perception in opposite ways. The writer tentatively connects 5-MeO-DMT’s distinct pharmacology with the cancellation and interprets the apparent push and pull between circles as suggestive of consciousness behaving like a computational or electromagnetic field. This is presented as a speculative update, not evidence for a theory. The proposed next step is a controlled study testing how often the effect occurs, how it relates to dose, and what model best describes it.