On 5-MeO-DMT, the Ebbinghaus illusion nearly vanished
5-MeO-DMT sometimes cancels the Ebbinghaus illusion
At a Qualia Research Institute retreat in Tepoztlán, the author vaporized 5-MeO-DMT and stared at the Ebbinghaus illusion. When he moved his attention to the space between the two circle clusters, their apparent size difference almost disappeared, as if the circles pushed and pulled on each other like fields. A later, higher dose produced no such effect. He notes that psilocybin has been shown to strengthen the same illusion, and suspects 5-MeO-DMT's preference for 5-HT1a receptors may explain the difference.
The illusion is effectively under volitional control. Move attention to either group of circles, and it looks as it does when I am sober. Move attention to the centre, the size difference almost disappears.
- cj
I can also eliminate the illusion by covering up the blue circles and only looking at the orange circles.
Maybe that's what the DMT is doing? ... perhaps it gives you tunnel vision (or tunnels your attention) such that you only "see" (or are paying attention to) the orange and blocking out the blue from your mind.
- mmsc
The "I measured my own susceptibility using an app I vibe-coded with GPT-5.6 Sol: I dragged a slider until the two circles appeared equal in size." is available on IA:
https://web.archive.org/web/20261008201251/https://heart.qri...
- kouru225
Well I guess I have to do the most powerful hallucinogen now. How else am I gonna save myself from the devious Ebbinghaus illusion?
- tim-star
i find this whole blog very dubious, with apologies to the author.
a bunch of people did psychedelics and then found that reality seemed more inclined to listen to their volition and respond to their intention or attention.
this was an n of some small number, and the original person who reported it could not reproduce it.
i don't believe this is good science.
the test is self made by the subject while under the affect of the drug.
the subject has a bias as well.
this is a trip report.
- drcongo
> But then I notice that when I move my attention to the centre of the picture — to the space between the two groups of circles — their apparent sizes begin to rebalance[...]
This works for me without DMT.