Lots Of People Going Around With Mild Hallucinations All The Time

[Related to: Relaxed Beliefs Under Psychedelics And The Anarchic Brain, HPPD And The Specter Of Permanent Side Effects]


Hallucinogen persisting perceptual disorder is a condition where people who take psychedelics continue hallucinating indefinitely. Estimates of prevalence range from about 4% of users (Baggott) to “nobody, the condition does not exist” (Krebs and Johansen). To explore this discrepancy, I asked about it on the 2019 SSC survey. The specific question was:

Hallucinogen Persisting Perceptual Disorder is a condition marked by visual or other perceptual disturbances typical of psychedelic use that continue for weeks and months after coming off the psychedelic, in some cases permanently. Have you ever had this condition?

2,234 readers admitted to having used psychedelics. Of those, 285 (= 12.8%) stated that they had some hallucinations that persisted afterwards. 219 (9.8%) said they’d had them for a while and then they had gone away. 66 (= 3%) stated that they still had the hallucinations (one limit of the study: I don’t know how long it has been since those people took the psychedelics).

But most of these people reported very mild experiences; on a scale from 1-10, the median severity was 2. The most commonly reported changes were more “visual snow” (ie “static” in the visual field), slight haloes around objects, and visual trails. Many people reported that if they stared at a textured area like a carpet long enough, illusory geometric patterns would start to form. Only a few people noticed anything weirder than this. Here are some sample responses:

— It took the form of visual disturbances (patterns, moving patterns, mild hallucinations like seeing a flower growing on a person’s face or seeing the legs of a chair walk). Initially there would be daily incidents. They seemed to be triggered by fatigue or other stress, and I did not like them, which lead to more stress. Exercise helped reduce the stress and make the visual effects go away. The severity and frequency dropped quickly at first and then more slowly over the years, essentially gone after a decade. I have had migraines with ‘fortification figures’ as well; this was different from that.

— Perceptual distortions about once a week. Difficulty concentrating for about 6 months. Intense interest in drawing.

— Used LSD about twice a month for a period of time when I was 17, and had a very very slight build up of persisting visual distortions. This phase culminated in me taking ~425µg by accident one night, and having a somewhat negative experience, had an ego death sort of thing, experienced strong “time-warping” where my subjective experience of the passing of time slowed down and sped up repeatedly by a large degree. Very strong acid trip. After that night I experienced pretty noticeable breathing on certain textures, like ceiling tiles, and a sort of “bright aura effect” on others, like pebbles. This gradually receded over something like 1-2 years, at which point it was entirely gone.

— straight lines often bend! it’s distracting!

— If I stare at an object, it’ll appear to slightly sway or move in a circular motion. If I stare at a surface (especially a textured one like a carpet), faint light patterns will develop. I got HPPD the 3rd time I did LSD. I haven’t done anything to treat it, expecting it would go away on its own over time. However, it’s been like 4 years and hasn’t really changed much. I’ve gotten used to it and often forget I have HPPD. I told an optometrist about it one time and he was just like “yeah, happens to some people who do acid.”

— Quite concerned. Seen by PCP and opthamologist. Performed a literature review myself and tried clonidine without a large effect. Symptoms have seemed to resolve however.

— Persistent discolouration blue-ward or red-ward, depending on *subjective* head orientation, in a pattern of visual field roughly equivalent to the Tetragrammaton. Yes bloody really. Help.

— My colour perception was distorted and confusing for some time, perhaps 1-3 years with browns, greens and reds, especially in natural settings (2C* series) I also experienced intense flashbacks consisting of bodily tingling and diffuse feeling of heat for ~10 months after a different psychedelic session.

— I see tracers, halos, have increased anxiety, visual snow. Nothing has helped so far.

— Very mild but persistent visual distortions. Walls breathing, kaleidoscoping of repeating patterns, etc. Not severe enough to warrant treatment.

— Any highly detailed or repetitive surface “breathes” after looking at it for even a few seconds. get glowing patterns when looking at some art, a sort of cycle of different colors being highlighted in sequence. makes eyes open meditation easier; makes “where’s waldo” harder.

— Visual snow; when viewing images which contain several different possible interpretations of patterns (eg hex grid on bathroom tile, carpet weaving pattern) my perception of the most salient pattern stutters and vacillates between the top 3-5 possible interpretations.

— I hesitated whether to even answer ‘yes’. 15-25 years ago, a period when I occasionally used psychedelics, I would sometimes have mild visual trails or aberrations when I wasn’t on any psychedelics. It never really bothered me. I can still sometimes make stationary patterns swirl or move by staring at them, but I think that’s just normal visual perception, not HPPD. Right?

A Reddit user helpfully illustrated what his (particularly severe) HPPD looked like (note especially the subtle square grid in left picture):

Weird, but not unbearably so. I think this explains the wide variety of prevalence estimates. Many people who take psychedelics will have very minor permanent changes to their vision. Most of them will shrug and get on with their lives. Only the few people whose changes are especially bad, or who get especially neurotic about it, will ever talk to a doctor.

I discussed some of this recently at a colloquium of experienced psychonauts (realistically: a group house full of the kind of programmers who go to Burning Man). Of the ten or so people there, two admitted to HPPD which sounded about as bad as the image above. They’d never really mentioned it before, it hadn’t come up, and they were living normal lives.

I conclude that lots of people you encounter are having mild hallucinations all the time, and it just never comes up.


I want to talk more about Krebs & Johansen, the paper that claims to find HPPD doesn’t exist.

First, it talks about surveys of special populations, like Native Americans using peyote. None of them report HPPD. Plausibly peyote does not cause HPPD (most of the people on my survey blame LSD) or something about the cultural set and setting prevents Native Americans from getting it during ceremonies. I see thedrugclassroom.com suspects this too.

Second, it talks about K&J’s own study, based in the National Survey of Drug Use and Health. Among 130,152 participants, those who have used psychedelics are no more likely to report symptoms than those who have not. But this survey violates one of the cardinal sins of psychiatric questioning – be careful in how you ask questions about psychosis-like symptoms! (see here for more people getting this wrong). K&J base their finding entirely on how people answer the question “Saw vision others could not?” (they don’t give the presumably longer question for which this is an abbreviation). But it is asked after several other questions clearly probing psychotic symptoms, like “felt force taking over your mind?”, “felt force inserting thoughts?”, and “heard voices?” Participants probably assumed (I think correctly; K&J did not write the survey) that the question was asking about more dramatic visions, like visions from God about their destiny or something. The average person whose visual field was 5% more staticky than normal wasn’t going to answer.

Third, it talks about HPPD-like visual hallucinations in people who have never taken psychedelic drugs. It says many people have them. I believe this. At the colloquium I mentioned, someone talked about having some similar staticky symptoms before taking any psychedelics. On my own survey, a few people said things like “I could always make the carpet self-organize into geometric patterns if I tried really hard, but after I took LSD it started happening much more”. I don’t know of any surveys on how prevalent this is, but since nobody has any trouble finding examples, I imagine it’s pretty common. My only argument that this doesn’t disprove HPPD is how many people – including my survey respondents – describe these oddities starting (or getting much worse) right after they use psychedelics. But we have no idea how many totally drug-naive people are just going around with weird visual experiences just because that’s the kind of person they are.


I want to talk about a case study of this last kind of person (as usual, this is a composite with some details changed to protect privacy). Patient of mine for a totally unrelated reason – she had mild depression after a death in the family, wanted to talk it over. Gradually it started coming out that she had an entire spiritual system based on what part of a grid she thought people fell on. It took me a long time to figure out the grid was literal. It was a shape she could see in her vision, all the time, close to a Cartesian plane but with a couple of extra lines and curves on it. It looked similar in spirit to the grid pattern tiled across the sample image above, though not exactly the same.

In terms of her personality – she was very into William Blake, Meister Eckhart, and ecstatic poetry. She dabbled in Wicca and occultism. She had strong opinions on chakras. Her hair was dyed an even brighter shade of purple than the Bay Area median. I was mildly concerned she was going to either join or start a cult, but she never went further than sharing some of her manifestoes about the nature of time-space with her lucky psychiatrist.

This woman had never used psychedelics. But her description of her visual grid matched some HPPD phenomena pretty well.

I still dream of linking individual differences in perception with differences in cognition. So I wonder: psychedelics make you more likely to believe woo, and more likely to have certain classes of visual hallucinations. But some people believe woo without taking psychedelics, and some people have those same visual hallucinations without taking psychedelics. Are they the same people? Do psychedelics move you along a natural axis of variation, maybe from unusually strong priors to unusually relaxed priors? Was my patient the sort of person that the rest of us would become if we took massive doses of LSD every day for years? Did that explain both her perceptual and her cognitive uniqueness?

Start thinking along these lines, and some other become pretty suggestive. How come some New Agey people say they can see auras around people? Are they just lying? Seems like a weird thing to lie about. And a lot of these people don’t sound like they’re lying. Aren’t auras a classic LSD hallucination? I understand they’re not quite as simple as the haloes around lights that HPPD people get; they’re only around people and sometimes the colors seem meaningful. But add something about handwave handwave using a special kind of visual processing for other people handwave synaesthesia, and maybe it’s not totally outside the realm of possibility? Maybe if your priors are so relaxed – ie so far towards the “naturally on LSD all the time” side of the scale – that you believe in auras, then your priors might also be so relaxed that you can see them.

We really don’t know what other people’s perceptions are like. At least, not until I ask a bunch of questions about this on the next SSC survey.

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145 Responses to Lots Of People Going Around With Mild Hallucinations All The Time

  1. emmag says:

    > How come New Agey people swear they can see auras around people? Are they just lying?

    I feel people’s personalities in felt-sense (the thing you do Gendlin’s focusing on).

    I imagine my emotions as a halo of colors around my body sometimes.

    These are almost never experienced as actual hallucinations where I “can’t tell if it’s real”, but I remember making much less distinction as a child between a “hallucination” vs a “internally imagined experience” vs a “real experience”, it was kinda all just… stuff.

    Sensoriums are constructed for agentic purposes, maybe people hallucinate people’s personality felt-sense as auras because it makes them feel more valid or it just looks cool, or whatever.

    There’s two conflated definitions of hallucination:
    1. can’t tell the difference from real sensations
    2. [overlaps with / may occlude / in the same space/field as] real sensations

    For example I can sometimes superimpose images on my vision so they occlude objects rather than use my “inner imagination”, but I find this difficult. I’ve met people who describe this as their default.

    • emmag says:

      There’s a much more important point here that I can only gesture at. See https://squirrelinhell.blogspot.com/2017/10/time-to-exit-sandbox.html

      There are claims that sensoriums are directly comparable, that there *is* a thing that *is* vision and it *can’t* have imagined objects in it unless you’re *hallucinating* is kind of just like, a narrative.

      Think about how you even learned a narrative of this form in the first place as a child. e.g. you described an experience, and your parent talked about your experience as if they knew things about it you thought they couldn’t have known.

      In other words, if you’re confused about how someone could have had an experience that sounds way too special, you’re actually having a political fight over who’s allowed to have what sensoriums, and if you got out of the car maybe you could have whatever sensorium you wanted https://slatestarcodex.com/2015/04/21/universal-love-said-the-cactus-person/

    • chridd says:

      > For example I can sometimes superimpose images on my vision so they occlude objects rather than use my “inner imagination”, but I find this difficult. I’ve met people who describe this as their default.

      As far as I can tell, I can’t do this at all. (Although for me for senses other than sight and hearing, I think at least sometimes there’s less of a clear distinction between imagining and experiencing… maybe.)

      • Purplehermann says:

        I have internal and external; concrete and abstract imagination. Abstract is much easier than concrete to use deliberately directly, and external concrete is way harder than internal concrete to use deliberately directly.

      • Taleuntum says:

        If you see a scene and then you close your eyes, Can you imagine the scene that you’ve just seen?
        If yes, can you imagine one extra object on the scene somewhere?
        If yes, when you open your eyes, can you superimpose your extra object on the same scene in the same place with the caveat that you still see the scene behind the object or you absolutely can’t do it?

        Also: When you were in a moving vehicle as a child Haven’t you played the game where you superimpose a long line coming out from you going to the distance and “slicing” the landscape with it?

        • Purplehermann says:

          Yes, with caveats- the more detailed the harder to picture, i can’t get anything extra details from re-examing the picture in my head as the entire mental picture is being forcibly held together consciously more ore less, and superimposing an object on vision is external concrete, difficult to do well or keep up for any length of time.

          I’ve been working on this for a little while, hopefully I’ll keep improving

        • chridd says:

          To the first two: yes, but while it’s visual data, it’s still clearly in my head, distinct from actual visual sensation (and also much, much, much weaker and less clear than actual visual sensation). (The “scene” I’m using is that of my laptop open to this webpage, and the object I’m imagining is a simple red cube that looks like it was made with computer graphics.)

          To the third: I can imagine an object in the scene, but it’s still clearly in my head (and everything else I said in the previous paragraph still applies). However, I can imagine it at a particular place.

          To the also: No, I don’t think I’ve done anything like that.

        • Aftagley says:

          If you see a scene and then you close your eyes, Can you imagine the scene that you’ve just seen?

          No, every time I close my eyes it’s just blackness. I literally learned this was a skill most people had pretty far into my life. What is this like. How often in your daily life do you do this? Is it useful in some way?

          No for the other answers, as well, obviously.

          • Taleuntum says:

            When i close my eyes, I also see blackness. I “see” my visual imagination in an other place not in my vision (I think). I only wrote the “close your eyes” part, to be sure that he really imagines the scene and not just sees it, but of course I can also imagine things in that not-vision place when I have my eyes open.
            Or do you mean you don’t have any visual imagination at all? I think it is orders of magnitude more useful than e.g. scent in my life. For example, can you do any kind of abstract math without it or enjoy books focused on a narrative?

          • Aftagley says:

            No visual imagination.

            I can expend a significant amount of energy to remember an image I’ve seen before, but it’s very difficult. It “kind” of coalesces into an image, but it’s more like a series of instructions, I guess? As in, this is the major shapes, these are the colors that should be there… etc. I can’t modify the images literally at all, and I’ve never thought that people could superimpose images onto reality until literally reading about it in this thread today.

            Abstract math – like what? I’ve got an engineering degree that required me to get fairly comfortable with math up to multivariate calculus and I could do that just fine. I found no correlation with visual imagination and I’m curious why you’d suggest there is one? Do you use your visual imagination to do math?

            Edit: I’m aslo really good at the “rotate this object in your head” puzzles and “identify the pattern and propagate it forward” puzzles you see on IQ tests and the like. I don’t use any visualizations on that stuff like I’ve heard other people do, it’s a skill I have.

            Enjoy books focused on a narrative – I mean, I enjoy reading and do so above the american average. I think I enjoy it, but it’s not like I’m picturing the events I’m reading about in my head.

            Actually, come to think of it, I tend to get bored by books that focus on visual descriptions and either skip over them or just stop reading them entirely if they are too much. I always just thought that was useless information the author was including for no reason. Do other people build mental pictures as they read, and do these kind of descriptions help?

          • Taleuntum says:

            I’m not familiar with engineering degrees, but maybe it is possible that you don’t really have to do creative math while being an engineer, only execute algorithms? Have you done a proof of sth alone? I use visual imagination even for simple things like “prove that there is an infinite number of primes”. Come to think of it, I use visual imagination even for algorithmic things if I don’t have paper, eg. can you solve 5*x+3=3*x-4 while you close your eyes? I hope you’ve done the degree some time ago, and you forgot what the relationship is between the roots(the x values where the polynomial is 0) of a second degree polynomial and the minimum/maximum place(the x value where the polynomial reaches its minimum/maximum). How would you arrive at the relationship?

            I’ve discussed the relationship between visual imagination and math with some of my mathematician friends before, but we were talking about how we imagine different mathematical objects, eg a group, or a subspace. It was assumed without any talk that we all use visual imagination for math, but I guess we shouldn’t have done so.

            How can you be good at “rotate this object in your head” puzzles, if you can’t imagine the object rotating? What do you mean it is a skill you have? You stare at the problem and the answer just comes to you? Similarly to blindsight?

            I often picture what I read, but not always and not in a detailed way. Descriptive parts tend to bore me often as well, but there are instances where they are interesting: when they give new information (more than what is explicitly written) when imagined, eg: I read a description of clothing and when imagined I notice that he is this particular cliché or I read a description of a landscape and when I imagine it, I notice that it is beautiful, the colors fit together nicely. But I imagine actions too, eg: this character hits someone. Interestingly I even visually imagined the previous, very vague example as a generic character hitting another generic character.

            Do you have inner voice ie a narrator?

            Do you know what I mean when I say the “sensation of seeing”? or when I say that it is possible that when you sense an object as red, when some other guy looks at that same object, he “feels” a color you would say is blue and there is nothing wrong with the eye/brain of the other guy and he sees the same wavelength of light and will report that he saw “red”.

            How likely do you think that you are a P-Zombie (the term sounds pretty offensive, but I won’t judge even if you are)? Are you confused about the term or do you think it is an oxymoron even after looking it up?

          • Aftagley says:

            Have you done a proof of sth alone? I use visual imagination even for simple things like “prove that there is an infinite number of primes”.

            I never was interested in proofs and haven’t done many over the course of my life. I can’t speculate on this one way or the other. I really found them to be tedious and too process oriented, but then again, I’ve never seriously studied or attempted them.

            Come to think of it, I use visual imagination even for algorithmic things if I don’t have paper, eg. can you solve 5*x+3=3*x-4 while you close your eyes?

            By this you mean 5 raised to the power of x and 3 raised to the power of x, correct? If so, no I can’t do that in my head, I would need paper. Anything more than one or two “steps” and I don’t trust my memory. If you mean 5x + 3 = 3x -4, yes I can do that in my head.

            You stare at the problem and the answer just comes to you? Similarly to blindsight?

            Pretty much, yeah. I’m not sure of the mechanism for why this is. If I had to guess, I’d say being too visually focused on an object makes you more likely to be biased on a particular answer, while I can just treat the inputs as data. That being said, maybe my brain is doing visual processes that I just can’t tap into.

            But I imagine actions too, eg: this character hits someone. Interestingly I even visually imagined the previous, very vague example as a generic character hitting another generic character.

            So, I don’t do this.

            Thinking about it, when I’m reading, the paragraphs I have the most processing at high speed are ones that are very action-heavy. If a section is just “character A does a thing, Character B responds, Character A blocks, character C obverses”

            I can have difficulty following it and will need to either slow down my reading, or reread a few times to ensure I get the sequence of events correct. I’d always thought this was just poor writing, I’d never considered they were writing for a visually oriented person.

            Do you have inner voice ie a narrator?

            Maybe? I can think and those thoughts always take the form of English sentences. I hold debates inside my mind where I simulate two different viewpoints and let it progress. This voice/voices are always something I’m consciously creating though, not something that exists independent of my will.

            I don’t have, for example, Morgan Freeman in my head freely commenting on my life. I can choose just not have thoughts – on long car rides where I’m driving I can spend hours just staring at the road go by not thinking about anything.

            Do you know what I mean when I say the “sensation of seeing”? or when I say that it is possible that when you sense an object as red, when some other guy looks at that same object, he “feels” a color you would say is blue and there is nothing wrong with the eye/brain of the other guy and he sees the same wavelength of light and will report that he saw “red”.

            No, this is utter nonsense to me. Not in the sense that I don’t believe you, just that I don’t understand it at all. Something can’t feel like a color (in my perception) it’s either red or it isn’t. Even when things are red though, I don’t “feel” like they are red.

            How likely do you think that you are a P-Zombie?

            No offense taken, I’ve heard it before and actually thought about this. Evidence for this hypothesis that hasn’t already been discussed:

            1. I don’t dream. I don’t mean I don’t remember my dreams, I mean I most of the time don’t have them. 99% of the time I will go to sleep and instantly wake up. The exceptions are if I’m really sick/chemically imbalanced where I’ll have dream-like events, but they don’t some to directly transplant onto what other people describe as dreams.

            2. I don’t seem to get emotionally attached to people. I didn’t really understand the concept of friendship or love until I pretty much made up my own definitions for those words that simulate, but don’t directly correspond to what I believe the commonly held definitions of those words are.

            3. If your definition of meditation is “get into a state where no more conscious thoughts are occurring and just exist there” I can meditate incredibly easily. I find this practice calming, but that being said, I don’t think I’ve experienced any of the other benefits people who meditate talk about.

            My argument against my being a P zombie (or, more accurately P zombies existing at all) is less structured. I enjoy my life. I have a semi-wide net of people in my life and, on the whole, I’m pretty sure I make their lives better for being in it. I produce value for society through my work. I am consistently funny and have a demonstrated history or responding to problems with creativity. I don’t perceive myself to have any kind of “lack” in my internal life. There are things that scare me and things that bring my joy. If there is some kind of afterlife, I hope to be included in it, but if there isn’t the idea of fading away into darkness doesn’t really hold any terror for me.

            I think I might be able to fit some people’s version of a p-zombie, but I personally don’t think I’m one. If I am, deemed to be one, then I don’t think that the term p-zombie is particularly meaningful in describing people.

            Edit: wow, even for me this was a long post. Sorry.

          • chridd says:

            For me:

            I don’t think I use visual imagination that much when doing math (though I might use it some? I’m not sure). I have done proofs. When I tried just now to do 5x + 3 = 3x – 4 in my head, my inner monologue (auditory imagination, which is much clearer than my visual imagination, and, like my visual imagination, is distinct from what I’m actually hearing) said the steps, like “five ex plus three equals…”. If I try to do math stuff like that in my head (or even mental arithmetic) I feel like I’m likely to forget some of the numbers, or at least be uncertain if I’m working with the right numbers.

            I haven’t read much fiction recently, but when I did I don’t think I formed particularly strong images most of the time of what was going on. (I’m not sure about the being bored about visual descriptions part, though, since it’s been so long. It’s entirely possible that I’d like visual descriptions more, because I want to form mental images and normal writing doesn’t do that for me.)

            I don’t think people have souls, so I think everyone, including me, is a P-zombie. I do have experiences and qualia, including visual experiences (and when I was young, I wondered if maybe there were people out there who experienced colors differently, like seeing red objects as I see green and green objects as I see red, without realizing it), but I think qualia is an aspect of how brains work and has nothing to do with people having souls. However, my lack of belief in souls seemed to cause some sort of internal conflict during certain times in my life (when I was experiencing derealization), so it may be that belief that I have a soul is natural for me and the reason I don’t believe in souls is purely intellectual.

            (Actually, somewhat going back to the main topic, when I experienced derealization some sensations felt particularly *strong* for me, like colors appearing *too* vivid and sounds *too* loud. The predictive processing thing seems like it might actually explain this, if some part of my brain was predicting a lack of experience, meaning that every experience above a certain threshold was surprising.)

            I do dream, and I remember my dreams frequently. There’s usually a visual component to what I remember from dreams.

            (Also, I’m a “she”.)

          • Aron Wall says:

            Interesting thread, but let’s please stop using the word p-zombie incorrectly. If you have any conscious experiences at all (e.g. qualia of any sense modality) then by the usual definition you aren’t a p-zombie. Period.

            I have a fairly strong visual imagination (but still much dimmer and less detailed than actually seeing something). As a theoretical physicist, I use it all the time to do calculations in my head. If I didn’t have a visual imagination at all, I don’t believe I would have been able to make a successful career out of physics.

            That being said, I also sometimes use auditory or even tactile imagination to think about mathematical structures. Really it is best to be able to flexibly think about things in as many ways as possible, switching from an algebraic to a geometrical point of view, and back again as needed.

        • Jonluw says:

          I find this topic really fascinating, and I wish there was some way to discuss it clearly. I’m similar to others in this thread that I do not seem to have the kind of visual imagination you describe.
          My specialization is in physics, but I find abstract math very interesting. Will you humor me by describing your experience in some more detail?

          If you see a scene and then you close your eyes, Can you imagine the scene that you’ve just seen?

          When i close my eyes, I also see blackness. I “see” my visual imagination in an other place not in my vision (I think).

          Let me describe my perception in as much detail as I can:
          If I close my eyes right now I see darkness. It is more like a dark void than a dark surface. At the moment it is tinged red due to light coming in from the left. It gets significantly darker if I cover my eyes with my hands. The darkness contains some white and yellow after-images, e.g., from the ceiling lights. The longer I keep my eyes covered, the more these after-images fade. In the end I am left with a nearly black void permeated by a gentle static, and very faint moving domains of slightly lighter color (reminiscent of storm clouds).
          The “presence” of this void varies with my attention. If I “focus inward”, my field of view becomes no less dark, but it is somehow “less present” in my mind.
          Occasionally, coin-sized flashes of light will appear in my FOV. They are primarily blue, but sometimes strange “oil-spill” colors flash (these are typically pinhead sized, and I suspect they may be the signature of an occasional alpha- or beta- particle). If I focus on the blue flashes they are reminiscent of aurora borealis or glowing puffs of smoke. I know from experience that if I keep my eyes closed for long enough (5-10 mins.), these lights can start to play quite actively in my vision. If they do, the colors tend to repeatedly start at the edge of my FOV and move in towards the center in a pulsing fashion at between 1/2 – 2 Hz. This behavior can be moderately affected by my will.

          So that’s the content of my FOV in detail.
          Now, if I close my eyes and try to imagine the scene which was just in front of me, here is what I experience:
          The imagination does not involve the FOV. In order to imagine, I need to “focus inward” as mentioned above, which causes the presence of the void to diminish.
          If I imagine sounds, such as the voice narrating this as I write it, the imagined experience is quite noticeably auditive, yet clearly separate from my sense of hearing (as a sidenote, I find it challenging to imagine sounds I can not produce with my mouth. Occasionally during states of hypnogogia I have been able to experience imagined music which blends far more with my sense of hearing).
          When I try to imagine the scene I just saw, on the other hand, I can not say the experience is noticeably visual. As mentioned, the imagination is separate from my FOV, but its character is far more “spatial” than visual. What’s more, it is very challenging for me to remember what the scene is actually supposed to look like. It is as if the visual information is almost entirely erased the moment I close my eyes.
          What I imagine instead of an image, is a space surrounding me filled with objects. There is no visual component to it as far as I can tell. One consequence of the fact that I can not recreate the earlier visual input is that when I picture the scene in my mind, the scene only contains objects which I’ve consciously taken note of. For instance, I experience the table and the laptop, their position relative to me, and roughly their shapes, but not the rest of the things on the table. For instance, there is a pile of books, keys, paper, and other miscellaneous items to my left, and in my “mind’s eye” these are all represented by an amorphous mass labelled “clutter” (Not literally labelled. Each object is simply associated with an abstract feeling representing its identity).
          Sometimes it feels like the “void” in my FOV is made of a dark substance and that my imagined scene is made by shaping this substance to resemble the shapes of my table, laptop, etc.

          When I work with math I use my “mind’s eye” to imagine straight lines, planes, etc. but these are not conjured as visual scenes. Instead they exist as spatial relations. Doing this, I sometimes get lost in thought and become uncertain if the experience is visual or spatial. However…

          Come to think of it, I use visual imagination even for algorithmic things if I don’t have paper, eg. can you solve 5*x+3=3*x-4 while you close your eyes?

          While I can solve that equation with closed eyes, it is very inefficient and prone to error. However, I can easily solve it in my head if I don’t close my eyes.
          The reason it is difficult to do with eyes closed is mainly that I can’t remember the equation as anything other than a string of words – “Five ex plus three equals three ex minus four” – which is very easy to mess up, especially since I am never representing the entire expression in my mind at any one moment.
          (Perhaps I should find some way to represent simple equations spatially. It might allow me to do algebra more efficiently.)

          It was assumed without any talk that we all use visual imagination for math, but I guess we shouldn’t have done so.

          You should ask your friends about this. After all, you don’t know what wordless assumptions the others made. According to the source where I first heard of aphantasia, the “condition” was apparently quite common among sciency types, and most of them just assumed expressions like “picture it” or “mind’s eye” were metaphorical.

          How can you be good at “rotate this object in your head” puzzles, if you can’t imagine the object rotating?

          In my case, I can imagine the object rotating, but the imagination does not consist of a visual experience.
          I’m very curious how you imagine an object rotating.
          What kind of space is the object located in while it rotates? Is there a background? Does it have visual features? Is it a uniform color? How do you keep track of what each side of the object looks like while they “face away from you”?

          Let’s say we have a sheet of paper with a yellow triangle on one side, and an inverted blue triangle on the opposite side. The yellow triangle is facing you, and points up. Now we are going to rotate the sheet 180 degrees along the long axis, and 180 degrees along the short axis. Which triangle now faces you, and which way does it point?
          In my case, here is how it goes:
          I construct a rectangular surface floating alone in the space of my mind. I experience it as an “outline” in the aforementioned void. Then I assign a “direction” to each side. I think I actually imagine the directions as triangles attached to the surface in this case. I also assign abstract identities corresponding to “yellow” and “blue” to the triangles. However, I do not actually experience the triangles as having any color. Then I rotate the rectangle as prescribed while I track the orientation of the triangles.
          During this process, both triangles are always represented in the “simulation”, even when they are on the opposite side of the “paper”.
          I’m very curious about how you keep track of the properties of the triangles while they are one the “opposite side” of the sheet in your visual imagination.

  2. Elo says:

    “And some of them are me/you”.
    on a simple map and territory level when humans stop assuming their map (visual field, cognitive beliefs) is the true information, they probably get better at reading reality than when they just believe their maps.

    Particularly around tribal beliefs, and “other” creatures (friend/foe belief).

    If someone can felt-sense through synasthesia type abilities or body based awareness and sense an aura, it’s not explicit map information but it’s cognitively processed information swiped off of system 1 processes (that time I met someone who gave me goosebumps and I concluded they were a creep… It’s not obvious information in the territory, but it’s information my s1 picked up better than my s2).

    And the true post-rationalist angle – maybe if we stop treating the weird lights and colours like useless noise, they will congeal into useful phenomena from which we can harness reality and win at life.

  3. Glen Raphael says:

    A Reddit user helpfully illustrated what his (particularly severe) HPPD looked like:

    Looking at that picture I have to ask, have they tried seeing an ophthalmologist and checking for cataracts? Because the “my vision” half of the image looks pretty much exactly the way my own vision looked when my own (fast, severe early-onset) cataracts started getting bad…and it mostly went away when I got cataract surgery, replacing my own natural foggy lens with an artificial plastic lens.

    Could what people think is a symptom of LSD use is really a symptom of aging? People differ in when they get cataracts and what they look like, but mine were like looking through the steam in a sauna, or perhaps wearing fogged-up glasses…and my eye doctors could SEE the fog I was looking though.

    This might also explain some of the “aura” stuff.

    (my after-multiple-surgeries eyes still do have some visual artifacts, especially at night, but these are different artifacts which can largely be explained with recourse to normal eyeball physics, not weird brain-chemical physics.)

    • chridd says:

      I wonder if HPPD and similar effects have to do with how much a person notices optical effects that have always been there. Like, I saw someone else talk about visual snow and afterimages; perhaps the actual strength of such effects doesn’t depend on HPPD but some people’s brains ignore them/filter them out until they take drugs, and the same could be true for cataract symptoms (they always had cataracts but now they’re noticing the symptoms more).

      • methylethyl says:

        Yeah, the first time someone told me about their LSD experience, it was kind of like: “You mean you’d never noticed any of that stuff until you did LSD??” I thought that was what everyone saw. Still not totally convinced that people who take LSD weren’t seeing that stuff before… maybe they were just *looking* for it after, because they’d heard hallucinogens could do that to you.

        When people report (like Oliver Sacks) that, say, a spider had a cogent conversation with them, or they met a transcendent being or they experienced one-ness with the cosmos, yeah, that’s totally an effect of the drug. Congrats on your far-out experience, man.

        But the rest sounds like ordinary visual “noise” that probably everyone sees to some degree, just most people tune it out most of the time. Or that’s my working theory: that I suck at tuning it out, just like I’m bad at ignoring itches, or other people’s telephone conversations.

    • Yair says:

      Yep, I agree, I also had early-onset cataracts and had the exact same reaction, that picture on Reddit looks like what a person with cataracts sees.

    • genocidebunnies says:

      Could what people think is a symptom of LSD use is really a symptom of aging?

      The first thing most HPPD sufferers do is go to an ophthalmologist. The second visit is usually to a neurologist of some sort. If these visuals were caused by mundane conditions (such as cataracts), they’d get caught. Not to mention that a fair share of HPPD sufferers are teenagers, at least judging by the relevant forums/subreddits.

  4. entognatha says:

    FYI for others noticing something familiar about the illustration: If you have distortions along the vertical or horizontal plane when looking at a bright light at night instead of seeing a round light, you most likely have a physical abnormality of the eyeball called astigmatism, meaning your eyeball is slightly oblong instead of round. This can be detected in a vision test.

    • Falacer says:

      Yeah I was going to say, a lot of this sounds exactly like my astigmatism. Without my glasses my eyes even produce movement in repeating patterns as they try and correct the blurriness.

    • chridd says:

      Are you talking about the six-pointed star shapes around the lights? If so, I notice there aren’t really any lights in the “normal vision” side, so I don’t know if the person who made the photo considers them normal vision (and/or if they were in the original image from the camera). (I think some sort of star-ish pattern around bright lights is normal. As far as I know, the grid isn’t. At least, I experience the former but not the latter.)

  5. drossbucket says:

    Interesting, think I might be in your ‘HPPD-like visual hallucinations in people who have never taken psychedelic drugs’ category, at the mild end. I’ve never taken psychedelics, but I get migraine with aura. Normally these are very irregular, but some time ago I had a phase where I had several over the space of a few months. After that I had noticeably stronger afterimages and more visual snow for maybe a year or so – not a very strong effect, but annoying enough that I kept changing web pages to light grey text on dark grey background, which triggered it less.

    At the time I had a pretty similar guess at an explanation – afterimages and visual static had become more salient to me, because sometimes they were the early signs of an unpleasant migraine, so they were getting promoted to conscious attention more than they would be normally. But I didn’t think about it very hard. And after a year or so it stopped being a problem, so I kind of forgot about it.

    • Murphy says:

      I remember a few years ago, was getting unusually stressed and got a migraine for the first time.

      Was sitting at my desk and realized I suddenly couldn’t read the text at the focus of my vision.

      I remember closing each eye and checking and being like “uh ok, this isn’t in one of my eyes, this is something in my brain” because it was the same with either eye.

      Really freaked me out.

      After a while the middle came back and I could read again but had a ring of distorting void expanded from the center point in my vision.

      a bit like this without the sharp border:


      Googled something like “expanding ring visual distortion” and one of the top hits was migrane aura.

      Pretty sure I sighed in relief audibly when I saw the stats for how much of the population get similar occasionally. I didn’t have some kind of stroke or brain damage, no it was just a fairly common migraine.

      I mean the migraine sucked that evening but after a half dozen over the next year I stopped getting them as stress reduced in my life.

      • Koan says:

        You’ve almost exactly described a similar visual distortion I’ve experienced twice in the past year – both times occurring the morning after drinking rather irresponsible amounts of alcohol the night before. The only difference for me was that the distortions were more like spots on cows, irregular (but well-defined) amoebas of blurriness across my field of vision. The effect lasted about 30 minutes and after I came to grips with the unnerving of discovering my new blind spots, I recall paying very close attention to them to try to determine their exact characteristics. Most of the time, when I focused on them, they were blurry and composed of the colors that surrounded them, but when I moved my focus away they became dark, or whatever the blind equivalent of black is. Oddly I’ve never gotten migraines following them though.

        After checking your link above and a little research, I think these visual distortions are technically termed scintillating scotomas and some of the causes (alongside tumors, strokes, and general head injuries) are chemicals such as methyl alcohol or quinine! I’m pretty sure my alcohol intake, excessive at it was those nights, did not include methyl alcohol, so it seems I will have to scale back on the gin and tonics in the future.

        While I’m somewhat relieved these visual artifacts are relatively common and non-permanent, I’m also unnerved at how effectively I managed to disable some part of my visual field. My brain is clearly not as (metaphorically) bulletproof as I like to take for granted.

        • Ransom says:

          This also exactly matches my own symptoms, but the middle portion of the “vision” has sparkly, geometric patterns. The slowly disappear in the center, then spread out as a ring. I’ve called them “opthalmic migraines” though they are completely painless, and go away after about 20 mins. They began when I was in my early thirties (and scared me badly at first), about once a year, more frequently in recent years. I understand them to be harmless. Hope that’s true.
          Never used anything other than alcohol and caffeine

    • methylethyl says:

      I get a bunch of that visual stuff. Never used drugs, but do get migraines. Wonder if it’s migraine-related. I know there has been at least one study that found migraineurs (but not the control group) were made uncomfortable by high-contrast patterns, even when they weren’t having a migraine. It suggests that the condition affects perception all the time, not just during a headache.

  6. Grek says:

    Wait, are the rainbow coloured lines that appear to swim around carpets and drop ceilings not a thing that other people see? I thought that was an optical property of whatever material they made those out of, but now I’m starting to think maybe it’s just me.

  7. simbalimsi says:

    Scott, I think you’d make the perfect psychonaut. I’d love to read if you decide to use some LSD and write about the experiences to us.

  8. Nancy Lebovitz says:

    “Was my patient the sort of person that the rest of us would become if I took massive doses of LSD every day for years?”

    Looks like a thinko there– do you mean what you would become or what the rest of us would become?

    I could make a joke about reading it literally as being the effect on everybody if you took insane amounts of LSD, but would it be a good joke?

    When I saw the title, I thought of the more usual claims about races and governments being hallucinations, but you’re aiming at something less drastic. Probably the most prevalent hallucination is excessive certainty about other people’s mental states.

    • Luke Perrin says:

      I assumed he was just using himself as a representative example of the-rest-of-us.

      But maybe I’m just imposing my too-strong prior for grammatical sentences onto sense-data that is in fact ungrammatical.

    • chridd says:

      I assume he meant “the rest of us would become if *they* took…” (or “we”?). As in, if any person not like that patient took LSD (could be Scott, could be someone else), they would become like that patient.

    • C_B says:

      > Probably the most prevalent hallucination is excessive certainty about other people’s mental states.

      Maybe the real psychedelics were the friends we made along the way?

  9. Ketil says:

    I can see a fairly clear aura – meaning a shimmering field, and inch or two wide – around people if I relax my vision and concentrate on looking past them. I can do this around any object with a bit of contrast to the background, so I think it is just an artifact of vision or visual processing. Never occurred to me to ascribe any significance to this, although obviously some people would and do.

    If you think you don’t hallucinate, I would point out that everybody goes around hallucinating that they see the entire field of vision, and completely ignore a certain blind spot.

    I don’t see shimmering bands of colors around carpets, and halos around lights only if I squint.

    And a famous author here hallucinated people and whatnot, and firmly believed this was evidence of her psychic powers, while I (somewhat firmly) believe it is evidence of her psychiatric illness. At what point do hallucinations go from harmless distortions like colors and halos, to psychiatric conditions (the voice of God telling you to do things you shouldn’t)?

    • Murphy says:

      meaning a shimmering field, and inch or two wide – around people if I relax my vision and concentrate on looking past them.

      Is this not just the border where you can see past an object in the foreground slightly more with one eye than the other due to parallax?


      Do you see it all around the object or more left-right than up-down?

      • elriggs says:

        Not OP, but I see “auras” and I also don’t think they encode personal information.

        Not parallax, but a legitimate color around the object. Like if you saw a light, then close your eyes, you see the afterimage of the light. But an afterimage all around the object you’re looking at.

        Like, you can look at the center of your head in a mirror for 1-2 minutes while paying attention to your peripheral vision, and you’ll see your “aura”. Having a white, solid color background might help, but I’m not sure.

        Just did this, and in 30 seconds I could see a green afterimage of myself around myself.

    • Enkidum says:

      If you think you don’t hallucinate, I would point out that everybody goes around hallucinating that they see the entire field of vision, and completely ignore a certain blind spot.

      Hell, you can’t see in much detail beyond about a 5° radius around the point you are fixating. Like, if you hold a playing card at about a 45° angle from your line of sight, you will probably not even be able to tell what colour it is (and certainly not what card it is). And we’re almost completely blind when we make saccades. Yet we experience the world as a consistent, complete, visual whole. I’m sure I’m preaching to the choir here, but yes, perception is an active process.

  10. Murphy says:

    Minor chime in:

    I’ve never taken any hallucinogen, if I stare at a surface I see faint visual “snow”, not quite like pictured but more like very faint shifting white noise like an old style untuned TV only very faintly colored. it’s not particularly distracting and doesn’t disturb vision because it’s as easy to “look past” as a very faint reflection in glass.

    Think a fair bit less gridlike/organised/regular than the picture.

    As far as I’m aware I’ve had it all my life, some of my very early memories involve wondering about it.

    No particular change over my lifetime.

    Always assumed it was just something to do with how eyes worked.

    Like something to do with my retina like how everyone has a blind spot.

    • Corey says:

      Me too. It’s mostly in my right eye, which is “lazy”, and so I just wrote it off to that. I also see geometric patterns but it’s mostly-consciously (I know I’m drawing imaginary shapes connecting stuff). Also never used hallucinogens (in my case, any illegal drug, or even Sched 2’s except for some time on methylphenidate).

    • I experience something like this which is so faint I would have chalked it up to being the visual resolution, as if I’m seeing the “pixels” on a screen. I can mostly only see it if I look into a dark area, or a large area of continuous color like a blue sky. Looking at bright objects I don’t see it.

      Do you also see colored blobs/afterimage type phenomena? I see those mixed in, and I can see them strongly if I close my eyes. I figure it’s some kind of false firing of the light/color sensitive cells/cones.

      • Murphy says:

        Pretty sure the afterimage’s are just the cells in the retina getting numb from too-bright light. Such as if you look at a lightbulb and end up with a blob/afterimage.

        But at to the faint resolution, ya, sounds familiar.

  11. stopandgo says:

    It took the form of visual disturbances (patterns, moving patterns, mild hallucinations like seeing a flower growing on a person’s face or seeing the legs of a chair walk). Initially there would be daily incidents. They seemed to be triggered by fatigue or other stress,

    I’ve had this a few times after 30 hourish flight plans and maybe a few other instances of extreme lack of sleep or general fatigue–patterns in tiles suddenly look like animals or other living figures and come alive a bit. (No history of psychedelics, but I’m sure lots of weird mental modules can kick in with enough fatigue.)

  12. Murphy says:

    Throwing another iota onto the fire:

    Apparently there’s a condition called Charles Bonnet Syndrome, often experienced by people who are losing their vision or parts of their visual field.

    In the areas of their vision where they’re losing sight they start seeing hallucinations. The patients are psychologically healthy, typically know the things they’re seeing aren’t real but also often worry about being considered crazy. It appears to be something like the brain being desperate to pattern match and when starved of input it can start filling in the blanks with faces and creatures.

    Like this:


    • a real dog says:

      It seems you can have some kind of overactive face detector, not even a generic pareidolia tendency but one focused on specific shapes.

      For instance, most of my friends see geometric shapes in the ground and leaves after psychedelics. There is one guy, however, that sees heaps of faces, Berserk/Kingdom Death style (https://ghostlightning.files.wordpress.com/2010/09/vlcsnap2010081920h17m08s189.png). Everywhere, including the ground he’s stepping on. Also half of his dreams, no drugs involved, are in the spirit of the split-second visions from Event Horizon – lots of gore and viscera flying around. Otherwise a cheerful and well-adjusted guy.

    • myla says:

      The brain is known to create signals when no input is detected after a while, that is most commonly seen in experiments about sensory deprivation. People see or hear things that are not there if they are in the dark or in silence long enough.

      I also can add to your words that older people and people who have lost their ability to hear more often start to hear sounds, music, voices. Oliver Sacks described this in his book “Musicophilia”.

  13. a real dog says:

    When I was bored at church as a child, I used to stare at things to make them breathe and slightly move relative to each other. I always assumed this is just a weird quirk of human perception and everyone can do it.

    Now I’m somewhat confused.

    Also, I had mild HPPD for a time (after about a year of using various psychedelics spaced 3-8 weeks apart) in the form of slight flashbacks in certain situations. It was nowhere as bad as the pic, I’d certainly seek medical help if that was my vision all the time.

    • myla says:

      It’s very fascinating that we of course all assume that some things are part of normal reality, especially as a child, but also as an adult.

      I just got reminded of a story (I probably read it here on SSC) about a person who didn’t realize they cannot smell and always assumed that certain behavior of people regarding fruits and farts is just common social norm.

    • FLWAB says:

      I concur. Since I was little if I had to sit somewhere boring for a long time (like math class) if I wanted to I could look at walls or anything with a repeating pattern and, with concentration, make them wiggle and dance a bit. I guess you could call it breathing. I too just figured this was a quirk of human vision, like blind spots. In one math class there was a grid made of blue painters tape on a whiteboard that I particularly liked. If I stared at it just the right way all the grid lines would slowly warp and then disappear, leaving behind clean white space.

      As to whether I’m more open to “woo”, I’m usually pretty opposed to woo in general. On the other hand, when I first learned about the Loch Ness monster as a kid I was instantly convinced it must be real. No hesitation. So maybe I’m a little more open? Its hard to tell, I was a kid.

      • Taleuntum says:

        Your experiences are very similar to mine, so I felt compelled to comment. When I was in high school and I had to wait for the tram to come, while I was sitting at the stop I often stared at the pavement (it was grainy) and I’ve also seen it move a bit. I also assumed (and still assume) that it is normal for everybody, but maybe not everyone notices. I haven’t tried since then. (i did it first by accident, but then I felt I could influence it by staring in a specific way)
        I never took any kind of recreational drug and only common medicines and I very rarely drink alcohol. I think horoscopes, fortune-telling, religion have no truth in them at all and I wear very standard type of haircut/clothes, but I think I am pretty open-minded in way that can’t really be perceived by others. (I don’t really talk much about my inner thoughts.)

        • FLWAB says:

          Tell me if you share this experience: have you ever been running at high speed and then stopped and any flat surface you looked at after stopping (like pavement, or a blank wall) looked like it was receding fromm you? Like it was zooming away, while still being the same size. Almost like if the hyperspace effect from Star Wars was somehow playing over it (that’s not really right, but it’s kinda close). Just a general sensation of movement, centered on wherever you are looking. It happens to me from time to time.

          I also have never used any recreational drugs.

          • Dino says:

            I’ve noticed this when I’m out riding my bike and stop.

          • a real dog says:

            I remember something similar as part of my HPPD, actually. Also once, having a fever, I’ve seen moving things rubberbanding (like in online games when lagged) – my movement prediction went too far, then jumped them back to their actual location.

            Also, I remain baffled that you can, indeed, perceive something as zooming away and keeping a constant size at the same time.

          • Taleuntum says:

            I have a vague memory of something like it happening, but I know how easy it is to influence people just by asking, so I went out to run around a bit and I couldn’t induce it. All in all, I think I did have that experience, but I forgot.
            Do you have the experience if you play this game with a speed around 1000-1100?

            Not exactly a visual hallucination, but related: Have you ever had any of the following 3 happen to you after doing an activity (for me e.g.: math, go(strategy board game), starcraft(an RTS), super meat boy(a platformer), tetris) for a long time/intensively:
            1. When you close your eyes, you see forms from the given activity. Not like a memory, rather like a fever-dream(I hope that’s the expression in english).
            2. When your eyes are open, you imagine (but not intentionally) objects from the given activity, almost see them, but you are sure in your knowledge that it is just an imagination.
            3. Sometimes notice that some of your patterns of thought match parts of the given activity. Sometimes it seems completely arbitrary and you can’t vocalize what is the similarity, eg. this thought is like a 6-pool, but sometimes you can, eg: a debate is like a game of go, people take turns saying arguments (~placing stones), some of them are good, some bad. You can try to evaluate how good an argument is by trying to anticipate counter-arguments and counter-arguments to the counter-arguments and so-on (~reading ahead), but you can’t perceive the whole of the game/argument-tree completely, so at some point you have to rely on heuristics and gut-feeling.
            I wrote this out now deliberately, but when I originally had it, it wasn’t verbal or intentional, it was like a feeling and the thought came as a whole, not linearly as in writing.

            Also, I know that the dominant view is that there are people who have an inner voice and some who don’t have, but to me the only people who said that they don’t have an inner voice were those who I can believe just simply didn’t notice it, and anytime I asked someone who I was sure would notice if they had one, always had it. Maybe you will be a counter-example to this: Do you have an inner voice?

            Sorry for the many questions, but I am generally pretty interested in others’ perception.

          • FLWAB says:


            Yeah, I do get it more when riding a bike. For some reason being in a car never does it.

            @a real dog

            It is baffling, isn’t it? I’m glad other people have experienced it because it is paradoxical to describe.


            Games don’t seem to trigger it, just running or bicycling at high speed. And even then not always, just sometimes.

            Unfortunately I don’t share any of the 3 experiences you outlined. If I play a game long enough I do tend to get terrible dreams that remind me a lot of your item 3 though: everything I do is just an extension of the game I was playing in mechanical terms. Somethings that state of mind sticks with me for a little bit after waking up. It is generally awful.

            I do have an inner voice though. Seems pretty clear.

          • The Nybbler says:

            I haven’t had that particular effect, but I have had other visual effects from hard exercise, and I suspect they’re actually related to physical effects from the increased blood pressure and rapid heart rate.

        • methylethyl says:

          Maybe most people just don’t spend enough time staring at walls?

          • FLWAB says:

            You may or may not be joking, but I honestly think you’re on to something here.

          • methylethyl says:


            Not really joking. Most people seem to have an extremely low tolerance for doing absolutely *nothing*. Thus the (otherwise inexplicable) appeal of Farmville. I was a weird kid, and spent quite a lot of wait time staring at walls and not thinking about anything. That was how I discovered the vortex illusion, the blue/red differential, and really had time to analyze the visual snow. Figured it was normal, but most people don’t sit around staring at walls and not thinking about other things.

  14. JPNunez says:

    Maybe before television and computers people simply didn’t have the vocabulary/concepts to talk about “staticky” vision?

    Then again, I doubt modern native population are so alien to those technologies that they still don’t mention this. We’ve had glass for a while too. Gonna go with peyote simply not producing HPPD for whatever reason.

  15. Enkidum says:

    If you ask random people questions about synaesthetic experiences, between 5-40% of them will endorse having had them. If you do more detailed questions, and run some kind of formal consistency tests, at least 0.5-15% will pass this stricter threshold (depending on the particular variety, yes I realize that’s a very large range). (This is orders of magnitude larger than the accepted estimates from a couple of decades ago, but more careful work has been done on this.) Most of these people will have never really thought that their perceptions qualified as special (and given the high prevalences, maybe they’re right).

    The most common is probably spatial forms of some kind, usually ways of organizing related concepts in peripersonal space. Most of these are probably much more mundane than what your patient described, things like calendars and systematic ways of organizing historical eras/dates. But there’s plenty of personality-related synaesthesias, both associating personalities with space/colour/whatever, and assigning detailed personalities to inanimate objects. Something like this seems similar to what your patient was describing.

    So yes, there are ways of experiencing the world in anomalous ways that are surprisingly common. I think synaesthesias are different from the kinds of lower-level visual effects you’re describing in most of this post (among other things, they tend to involve the systematic organization of learned categories), so when you add together synaesthesia and HPPD, and likely other anomalous perceptual states, you end up with at the very least a substantial minority of people, and possibly even a majority.

    Always struck me as unfair, I have extremely good vision and despite taking a fair chunk of LSD back in the day, I never had any hallucinatory experiences beyond mild texture/surface stuff, and things like seeing the spaces in between tree branches a bit like stained-glass windows, but always very mildly. (Then again I had something like cognitive hallucinations, where I got confused about reality in rather unpleasant ways that persisted beyond the trip, but that’s another story.)

  16. elevated_square says:

    Does anybody know whether some cases of this mild HPPD gives people a greater ability to discern subtle changes in their environment? I.e. in a reply to my comment on your previous topic of ‘relaxed beliefs’, Buttle mentioned noticing a rainbow iridescence under clouds during a trip which have remained with them since (presumably these are actually real, I’ll keep an eye out).

    Working in a lab often requires me to make judgement calls working with very little visual information, i.e. looking down a microscope and focusing on a increadibly thin ring of fluorescence, or determining the order of elution down a chromatography column in an unlit chemistry lab (dangerous, yes – photolabile compounds). As a side note I always enjoy driving in the pouring rain.

    Did MK ULTRA try training snipers to scan their visual field under the influence of LSD? Kinda risky if severe HPPD develops I suppose.

  17. Pete Michaud says:

    My pet wild-ass-guess about HPPD has long been that:

    1. Visual perception is actually noisy, distorted, and weird.
    2. We don’t normally notice this because our visual processing software cleans up the image in a top down sort of way, to make it orderly, sensible, and stable.
    3. Psychedelics relax our priors (I wouldn’t have used that phrase before, but it fits nicely) about what we’re seeing, such that the bottom up, more “raw” sensory input gets higher priority, so we’re actually aware of the unprocessed weirdness.
    4. And that some people have those more relaxed visual priors kind of stick, as if the network was updated in favor of the weird static and patterns.

    I think people vary in the degree to which their perceptions are top-down vs. bottom-up dominant, and it makes sense to me that people who are more bottom-up would tend to have these more raw visuals stick around once the spell is broken, so to speak, on the top-down post-processing.

    It also tracks nicely with cultural tropes. Literal art school training includes heavy elements of learning how to see, which means looking at a scene or a person and seeing what is actually there, in terms of shape, color, etc, instead of an abstracted–almost iconic–representation/interpretation of what is being seen.

    — Digression —

    I can tell you from experience that it is a remarkably different mode of seeing. I, and I think most practiced artists, can “switch modes” basically at will, and it’s hard to describe to someone who has never experienced it, but the effect is profound. In normal mode, the visual field is sparse and, maybe “efficient,” I’d say. Like, I get what I’m looking at without attending to it too much. I see a wall and it’s “tan.”

    In “artist mode” or “actually looking mode,” the visual field is almost overwhelmingly dense with information. It reminds me of semantic saturation (say a word enough in quick succession and it no longer sounds like a word, but rather a non-symbolic blob of sound)–in this mode it takes extra effort to see that I’m looking at, say, a “face,” rather than a non-symbolic field of light and shadow. It’s remarkably useless for something like hunting, but basically the only way to do something like paint a portrait. That same tan wall is no longer “tan,”–although I can still see that in some sense, under ideal conditions, it is correct to call it tan–it’s now a really complex field of gradients between blue-gray, yellow-gray, and green-gray. In this mode I can see what could easily be described as halos and auras, although I can tell it’s mostly the effect of contrast and shadows.

    –/ Digression —

    Artsy people correlates with new age people, maybe correlates with visual “distortions.” Scare quotes because under this theory, the distortions are actually just visual sensory data that’s less cleaned up by post-processing / symbolic meaning-making.

    • keaswaran says:

      The four point explanation you give is exactly what I’ve generally thought.

      I have no experience with visual arts, so I don’t have any thoughts about the second half of what you wrote.

      When reading the HPPD descriptions in the original post, I had nothing that related to the “visual snow”, or most of the other descriptions, except the last two descriptions sounded exactly like my experience. (Can vacillate between multiple plausible interpretations of a scene with repeating patterns; can get complex visual patterns to slightly move when staring at them with the right sort of attention.)

    • noyann says:

      Literal art school training includes heavy elements of learning how to see [ … ]
      I can tell you from experience that it is a remarkably different mode of seeing. I, and I think most practiced artists, can “switch modes” basically at will [ … ]
      In normal mode, the visual field is sparse and, maybe “efficient,” I’d say. [ … ]
      In “artist mode” or “actually looking mode,” the visual field is almost overwhelmingly dense with information.

      I have that with reading and words. On a spectrum from just getting mundane info input to a sensuous reveling in the ‘felt sound’ of a word or phrase or verse. The latter often comes with a feeling in the mouth that is not really a taste, nor really a texture. Not subvocalizing either, it is very sensual.
      This capacity for ‘language intoxication’ was increased or trained by reading ‘Stein on Writing’ (other books on writing as well, but this had the strongest effect). I see this reading as similar to wine tastings; afterwards one consumes with more awareness and enjoys more. Side effect: I have become touchy to carelessly written or spoken copy text.

  18. myla says:

    This is a cool topic and I would like to share a phenomenon I always had with closed eyes (since I was a child) and I always assumed that everybody sees it that way, since I thought it’s just how your eyes/neurons work with no input. Maybe I am right, but how could I know?

    So what I see with closed eyes (especially after a while and while it’s fully dark) is a faint, colorful “leaves of autumn” like pattern that just swims around in front of my eyes. Usually it tends to form into a 3D-like complex cavern (that is in constant change) I randomly fly around in. I also remember times when I was able to have an influence on the direction I am moving or even speed, but that’s not the usual case.

    Can anybody falsify this pattern please by describing what he sees with closed eyes? You could also confirm, but that doesn’t mean that much right? 😀

    (What I also see with closed eyes are the more obvious areas of colorspace that may be just the afterglow of your recent visual field of course, but they fade away after a while.)

    • I definitely don’t see an evolving 3D cavern, but my impression was that everyone sees some kind of visual snow and shifting colors when they close their eyes, and then their imagination can go to work with those shifting colors. I think the theory about having no input may be correct, but I see a very very faint version of this when I have my eyes open, so it may be more of a misfire thing.

      • myla says:

        Thank you, I was more interested in the visual snow/colors, the 3D “cavern” really just emerges while concentrating. I know what you mean when you say that you can see it with open eyes. Like watching this comment section (which is white on my screen) doesn’t appear flat white, but speckled in a faint way (and I don’t mean the pixels).

    • FLWAB says:

      I concur with your experience. When I was bored as a kid I used to close my eyes and try to fly around a bit. It’s hard to get it going: you might say it takes a lot of concentration, but it’s the kind of concentration you need to make a magic eye picture work. If you think about it too hard it goes away. But besides the usual snow and the bright “donut” ring that appears when you look at something bright and then close your eyes, I could occasionally get actual images. Always dark and in weird colors, a bit like wireframe graphics. The most complicated one I ever conjured was a strange city at night, and I could fly through the streets at will. Since I’ve gotten older it has been much harder to see anything besides donut rings and static, but if I spend a lot of time at it I can usually conjure some kind of image. Not any particular image I want to see, but something.

      • myla says:

        Very cool, since the magic eye pictures you mention describe the 3D effect that comes out of the noise perfectly and I even thought about it while writing it. 😀

    • The Nybbler says:

      I see only the afterimages, in monochrome — a dark reddish-orange for dark areas and yellow for the bright ones . The afterimages do move/shift and fade until I’m seeing just random patterns.

    • dont-want says:

      When I close my eyes, I see something that starts like an afterimage and turns into white noise (though purple-orange-brownish) within 5 seconds. I always thought, and still think, this is physical, because I can create patterns in it by squinting with closed eyes or applying pressure with my fingers.

      I just read the Wikipedia article on „Closed-Eye hallucinations“, and now I am confused, because it claims that, unlike the pressure-related things, not everybody has them, and they are distinct phenomena — but the two have the exact same quality for me, they differ only in magnitude, and they transition into each other.

      And I just followed the recommendation to try and see them on a uniform-colored surface with open eyes, for the first time in my life, and yes, it kind of works.

      It still seems ordinary and unremarkable and physical and unrelated to what happens when I take psychedelics, which I have done.

    • a real dog says:

      For me the most common CEV is like a light color that is then “eaten” by a dark color from the outside, then that one is “eaten” by a light color again ad infinitum. Kinda like mixing paints I guess? It’s also a lot more pronounced when I’m falling asleep.

      When I was a child I used to see colorful stars on brownish background with eyes closed. Now it only happens on drugs. Gimme back my stars, brain.

      • myla says:

        Yes, those descriptions of light areas eating dark areas in a loop fit my experience too. But I would categorize those effects just as the afterglow of recent light sources your eyes have catched.

        Your “colorful stars on brownish background” is probably what I described as “leaves of autumn”, the faint spots that appear when you have your eyes closed long enough and don’t focus on the afterglow stuff.

    • Majuscule says:

      When I close my eyes I also quickly get some sort of kaleidoscopic pattern of light and dark. Sometimes it’s more geometric, and sometimes it indeed follows the “light eating dark” alternating pattern of concentric shapes or electric blue waves that persist for a while when I open my eyes. I can also get pretty vivid representational scenes going if I let my mind go there. I don’t usually want to, though, because usually if I’m lying in the dark with my eyes closed, I’m trying to sleep and this sort of thing isn’t helpful.

      For the record, I tried a very conservative dose of shrooms once (hallucinogens kind of freak me out but I was curious enough to try them). I saw something very similar to the electric blue tracery surriounding objects that I had seen before in the dark. I also saw patterns appear to move during that experience, so I assume I understand what some of you are describing, but nothing like that has appeared for me afterward.

      This ties into a discussion we had at the last Philadelphia meetup about our individual capacity for visualization. I think I must have a pretty decent ability to visualize. For example, we asked each other to visualize an apple. I seemed to have a considerably more vivid apple in my mind’s eye than some folks at the table. I could also “see” it superimposed on part of my field of vision, actually in a very specific location, something I had never realized or considered until that conversation. I like to draw and always did well on spatial reasoning tests. I can manipulate geometric shapes in my mind’s eye and stuff like that. I wonder now if there’s a spectrum for how easily people pass information back and forth between the eyes/visual processing centers and the rest of the brain?

  19. Dacyn says:

    For comparison, lots of people (i.e. ~20%) have mild auditory hallucinations all the time, though this has nothing to do with psychedelics. My experience is that usually you don’t notice anything unless you’re reminded about it, at which point you can’t help but notice.

    • BlindKungFuMaster says:

      I used to hear my name a lot when I was a teenager. It just popped out of music or random noise. Like faces jump out of random patterns.

    • methylethyl says:

      Yes. I have mild tinnitus all the time. But usually only notice if I’m thinking about it.

    • helaku says:

      Can confirm. I have a relatively constant white noise in one ear. It’s somewhat annoying.

  20. herbert herberson says:

    I saw person-specific auras on an LSD trip once. It’s not something I’ve ever spent a lot of time thinking about or believing in, so I’m more likely to attribute it to an artifact of the visual processing system than a more psychological one.

  21. Doesn’t everyone have some level of visual snow? I always thought that it was like this and people just fell on a gradient of severity. What I can see is a very very subtle effect of TV static, almost like my vision is made up of incredibly tiny pixels which I can only see when I look into shadows or into a blue sky, and I can also see sporadic and very faint splotches of color disappearing and reappearing, which may be afterimages. I can’t see it at all if I’m looking at brightly lit objects.

    It’s very much like what most people I know report when they close their eyes, but when my eyes are open. Only it’s so subtle that I would never think to report it as a “visual hallucination”. I would have previously said that it’s just the natural imperfection of the visual system that exist on a microscopic level.

    EDIT: I also used to have outright hallucinations when I was a young child, but I’ve never had those since then, and it’s definitely not the same category of phenomenon. I used to clasp my hands over my ears and I would be able to see a weird tribe of tiny people. I used to laugh manically while my eyes would pivot around violently, and I would repeat things they would say. For a while they were my friends, but eventually they started threatening to “KILL THE BOY! KILL THE BOY!” and boil me in a pot, and I don’t remember any of the hallucinations after that.

    I think that’s more autism spectrum stuff coupled with the imaginary friends/enemies concept than anything else though.

    • myla says:

      I can agree with your experience of visual snow, with open eyes and closed eyes. But it was always like this, before and after psychedelics.

    • broblawsky says:

      I can’t speak for other people, but I’ve never had that “visual snow” experience.

      • myla says:

        Hm, it’s not an obvious snow that’s in your line of sight or anything, not something you would really see if not looking for it. But when watching a plain area of say white background, does it appear without any spots/dots?

  22. RomeoStevens says:

    I can click auras on with mild effort. They seem to just be relaxation of some parameter in the edge detectors. They vary based on background colors and lighting conditions, not deep truths about the person’s emotions or whatever. They look like standard afterimages by themselves but can interact with other visual effects too.

    There’s also a sense of having some control over how top down or bottom up the visual system is being. I can snap to strong top down (noisy visual field can resolve into geometric patterns) or strong bottom up.

  23. jplewicke says:

    I think my previous comment on HPPD And The Specter of Permanent Side Effects might be of interest here.

    I think that you can explain this with a combination of the predictive processing model and analogies to insight meditation. I think the resulting explanation also applies to the stages of insight meditation from Mastering the Core Teachings of the Buddha(MCTB) and stuff like Kundalini phenomena as well.

    So the basic predictive processing model says that there’s a process of reconciling different predictions between top-down predictions with bottom-up sense data. At first the top-down model just overrides the bottom-up sense data. Each time the bottom-up data is surprising, this releases some small amount of a neurotransmitter. Eventually some cumulative threshold is reached and the top-down processing neurons starts noticing that they’re encountering errors and surprising information. They start to try to adjust their output to try to accurately predict the bottom-up data, emitting some slightly different neurotransmitters in the process. Eventually a combination of the right neurotransmitters and developing a better model of the world through trial and error allow both the top-down and bottom-up models to come to a mutually agreeable and consistent view of the world, and the basic phenomenon isn’t surprising anymore.

    The basic premise of insight meditation is that most people’s top-down priors about their subjective experience of the world are incredibly wrong, in ways that are hard to understand until you’ve paid close enough attention to the details of your subjective experience. This includes stuff like believing that you’re a separate agent interacting with an objective reality, that objects continues to exist in your subjective experience even when you’re not thinking about them, and just generally that everything is way more solid and long-lasting than it actually is. Insight meditation or psychedelics are both methods for directly experiencing that that’s not true and changing your top-down and bottom-up models of the world.

    Insight meditation follows the basic predictive processing model of trying to reconcile erroneous top-down perceptions to noisy/surprising bottom-up sense data. The difference is that insight meditation involves huge swathes of the brain, and that it involves having hugely surprising and improbable experiences. That adds up to megadoses of neurotransmitters being released, with the exact mix of neurotransmitters depending on where the brain is at in the process of reconciling top-down versus bottom-up data. The experiences of insight meditators can thus have a common similarities in how they’re experiencing the world, since the sequence of neurotransmitter release and surprise-reconciliation strategies changes in a predictable basis. This is the basis for the Progress of Insight stages that Daniel Ingram writes about in MCTB. When it comes to the states in concentration meditation, I like Leigh Brasington’s article on the neural correlates of the jhanas, which are a set of commonly-experienced states in concentration meditation. I haven’t read Surfing Uncertainty, but I’d bet that there’s a lot of overlap in the neurotransmitter sequence from the predictive processing model and in Leigh Brasington’s sequence of neurotransmitter evolution. And there’s definitely an overlap between the insight stages and the concentration states — Daniel Ingram discusses a mapping of this in his chapter on the vipassanna jhanas.

    So what does all of this have to do with HPPD? Well, I beleive that predictive processing says that groups of neurons that consistently come up with surprising information get rewarded and listened. And insight meditation says that our priors about our subjective experience of the world are extremely wrong, and that the reality of what’s going on is extremely surprising. This difference between our current priors and reality means that any parts of our brain that know the right way to look have an abundance of things to point out as really surprising. And each time they point that out, they get rewarded with neurotransmitters and being listened to a little more carefully.

    Under normal insight meditation conditions where someone continues practicing and is doing so deliberately, this happens mainly from the viewpoint of the person who is meditating, and they feel like it’s under their conscious control. But in the case of HPPD there’s no reason it couldn’t be a rogue group of visual neurons deciding to continually point out visual snow, or to point out that their perception of the wall changes many times a second based on new neural pulses. And in the case of Kundalini phenomena, there’s no reason that the neurons behind a basic physiological drive like lust or hunger can’t suddenly say “Wow, if I pay attention to the impermanence of sensations in this insight-meditation-like way, then I can constantly reap the rewards of lots of dopamine.” I like Kevin Simler’s discussion of this in Neurons Gone Wild, from his excellent blog post series.

    • elevated_square says:

      While this raises some interesting ideas I can’t accept the notion of neurons having intent. They don’t receive any ‘reward’ when dopamine is released upon their dendrites – it is activation of specific circuits which evokes a pleasurable response in an organism. They simply alter their firing properties in accordance to changes in input over time.

  24. Hackworth says:

    I wonder if and how “simple” optical illusions are related to HPPD, in the sense that HPPD is merely a natural behaviour or failure mode of the brain, amplified or de-inhibited by psychedelics. There are many still pictures designed to immediately start moving as you focus on them even when you have never taken psychedelic drugs. How do we know those to be different from carpet patterns starting to move because of HPPD?

  25. viVI_IViv says:

    2,234 readers admitted to having used psychedelics. Of those, 285 (= 12.8%) stated that they had some hallucinations that persisted afterwards. 219 (9.8%) said they’d had them for a while and then they had gone away. 66 (= 3%) stated that they still had the hallucinations (one limit of the study: I don’t know how long it has been since those people took the psychedelics).

    Are we sure that these hallucinations are caused by psychedelics?

    Given that the prevalence of clinically diagnosed schizophrenia is about 1-1.5%, it doesn’t seem that implausible that 3-10% of the population has some mild visual hallucinations, at least for some time, just due to their own brain quirks.

    Third, it talks about HPPD-like visual hallucinations in people who have never taken psychedelic drugs. It says many people have them. I believe this.

    Indeed this is to be expected.

  26. Roepke says:

    Re linking cognition to perception: Perhaps the most spectacular theory on this subject is in Oswald Spengler’s Decline of the West. He argues a form of cultural fundamentalism where everything in a culture, from mathematics to religion to art springs from the fact that they all have, of all things, a different experience of depth perception. So the ancient Greeks saw the world as solid bodies interacting, so their art was sculpture, mathematics was geometry, and ethics was virtue based eudamonia ethics. Whereas the Europeans are the ones who conceive of the world in terms of 3d coordinates extending indefinitely in every direction, so their art is symphonies, religion is monotheism (roughly, this depth perception provides a way of conceiving how God can be everywhere), and mathematics is based around functions (conception of continuity from this depth perception).

    He’s a very good writer and fairly knowledgeable (at least about ancient and European culture) so his work is worth reading, even if his fundamental theory is about as ludicrous as a theory can possibly be.

  27. Sigivald says:

    But we have no idea how many totally drug-naive people are just going around with weird visual experiences just because that’s the kind of person they are.

    Just like, say, the previously posted about afantasia?

    “I had no idea everyone wasn’t like this.”

  28. embrodski says:

    Dating someone who described what having sex is like to her, and I recognized it immediately as sex-on-LSD. And I’m like “Do you do LSD every time we have sex?” and it turns out no…. that’s just what sex is like for her ALL THE TIME. Needless to say, she’s very sex-positive.

    She also has occasional vivid visual hallucinations that I would associate with LSD (eg: seeing a cat at all stages of its life simultaneously, including decay), again while sober. Has had a big impact on her life and views on nature of reality.

    • a real dog says:

      Hey what the hell, I was asked by a girl whether I have visuals during sex, she thought that it happens to everybody. So maybe a significant portion of population does have this quirk?

      The rabbit hole of mind differences goes deeper still. Scott, I hope you’re making notes for the next SSC survey.

  29. methylethyl says:

    Wait, really? Those things are considered hallucinations?

    Count me as one of those people who see them all the time, but have never used psychedelics, unless I was dropping acid as a baby and just don’t remember 😉 Like, really. I don’t even drink alcohol.

    But 100% of the time, I do see:
    tracers (trailing afterimages)
    visual snow
    blue/red differential
    all geometric patterns move
    (high-contrast striped wallpaper makes me nauseous)
    object halos
    visual—>sound synaesthesia (sudden sharp noises cause visible white flashes of light)
    Bright light+flat backdrop such as a blue sky or a wall= vortex illusion.
    And sometimes, when I’m tired, eat certain foods like apples, or during migraine prodrome, the floor ripples.

    Except for the white flashes (I sometimes went looking for the light source), I never mistook these phenomena for *real*. I knew they were visual anomalies. They mostly don’t get in my way. I ignore them.

    Didn’t realize until college that *everyone* doesn’t see that stuff until college. My roomies describing LSD experiences seemed… incredibly boring.

    FWIW, I’m religious, but I don’t link the visual phenomena with anything spiritual, 99% of the time. There have been a couple of occasions where the visual phenomena were more organized and may have crossed the line into religious/mystical experience: I do not discount the possibility that those are *real* in some sense, but I also try not to put a lot of weight on that. Because they might just be… hallucination. Whatever.

  30. thinkingfor10minutes says:

    The year I started experimenting with psychedelics my imagination (the ability to visualize things) improved. The most noticeable difference was reading books. Before I was finding hard to visualize scenes and I never enjoyed doing so. After experimenting I could visualize scenes much more easily, scenes or character appearances would pop in my mind effortlessly and I actually found myself enjoying books more.

    I also got mild HPPD-like symptoms (milder than on Scott’s picture), which never bothered me. Also, I can (semi-) consciously control the intensity a little bit.

    I am wondering if ability to visualize and HPPD are linked together. Could this be tested? People with aphantasia would have lower rate of HPPD. And people who noticed improvement in their ability to visualize after experimenting with psychedelics would br more likely to also develop HPPD.

  31. A1987dM says:

    Pictures like that one make me instinctively want to clean my glasses. (I wear glasses about 100% of my waking time, and my brain must have learned that by far the most likely cause for seeing stuff like that is dirty glasses.)

    • myla says:

      Very funny, the eyes seem particularly good in ignoring dirt on your glasses in the meantime though. 🙂

      I was once fooled when looking at a straight line that was bent and I didn’t instantly realize that my glasses were the cause for this. Okay, that get’s really off topic now. 😀

  32. The Nybbler says:

    I used to be pretty interested in visual perception and illusions. IIRC, stuff like seeing spurious patterns on patterned and detailed surfaces, or switching between 3D interpretations of 2D images, or all sorts of weird stuff when staring are all normal things and the basis for many optical illusions (including some which have been posted here). So I wonder if the people complaining about this just didn’t notice before they took psychedelics, or if it got worse, or if they’re staring more.

    @Pete Michaud mentioned artist’s vision. One of the things artists train to do is to “draw what they see”. I think part of this involves turning off or bypassing the 3D interpretation we normally do and seeing objects as lines and spaces. I wonder if drugs may cause this to happen spontaneously. (I can if I try hard see a wireframe 3D cube as 2D, but it’s a recipe for a headache)

  33. broblawsky says:

    Could this effect be related in some way to meditative states? Because I’m an extremely novice-level meditator, and I get hallucinations while in a meditative state pretty regularly. Based on other people’s reports, that seems to be unusual.

  34. dark orchid says:

    There’s a journalist and author called Graham Hancock who has a line of books exploring big open questions like “what if the pyramids were built by atlanteans as a warning to future generations?” So far, so woo but his book “supernatural” has the central thesis that a small percentage of the population spontaneously hallucinate and that this is what started our species off creating art and culture.

    From memory (it was a while ago), most of the first half is about prehistoric cave art (theory: people were hallucinating and then painting what they saw), moving on to shamanism in various cultures (again, hallucination – some get there with drugs, some with exhausting hour-long ritual dances and rhythmic drumming, others can just do it), and then the second half is about how alien visions, and alien abduction in particular, could be people spontaneously hallucinating without any control over it, but interpreting this in terms of their modern culture.

    It’s part woo, part chronicle of the average number of circles and lines in different painted caves, and part really fascinating.

  35. alwhite says:

    I managed to give myself a tingling sensation in the face through meditation. It faded after 3 or 4 months of no meditation, but comes back if I start seriously meditating again.

  36. Dallon says:

    Oh this is interesting! I’ve always had mild visual snow, and textured surfaces often look like they’re shifting or breathing, but I just assumed it was the kind of boring normal thing everyone experiences and doesn’t bother mentioning. I’ve done mushrooms once but this has been there for as long as I can remember.

  37. Bram Cohen says:

    That picture is a great illustration of what the world looks like on LSD.

    People seem to experience auditory hallucinations in a very different way. Like normal auditory perception is half hallucinations filling in the details in what you’re hearing, and that’s just normal. Most people occasionally experience tunes getting stuck in their head. I have continuous, never-ending music playing in my head which is just barely on the imagination side of the intense imagination/hallucination boundary. I’ve never thought of this as hallucination though, and never realized it isn’t the case for most people until adulthood. Trying to suppress it is bad and makes me get OCD symptoms. Yes it makes meditation impossible and yes it’s distracting.

  38. Steve Sailer says:

    How many people who didn’t take part in the survey would have if they hadn’t wrecked their brains with hallucinogens and now can’t follow Scott’s chain of thought?

  39. Bugmaster says:

    I’m just chiming in with my own anecdata point regarding the “my vision” image: at least some of those artifacts are not indicative of hallucinations, but rather ocular damage. See an ophthalmologist !

  40. ajwt says:

    I feel I can relate to this somewhat; ever since getting heavily involved in lengthy meditations, dating a girl who was really into astrology, reading classical stoic and sceptic philosophy and generally becoming more sceptical about whether reality is as it appears, my perception of vision has definitely changed somewhat. I catch bizarre distortions in my peripheral vision all the time, and more recently it encroaches the centre of my visual field more often. It’s notable, but it’s never a bother and is the sort of thing I would probably never discuss with another person unless prompted by something like this. Incidentally I have always had a large number of floaters in my eyes for my entire life, to the point where I was surprised to learn as a teenager that not everyone experiences that.

    An important corollary to Scott’s point near the end of the above: we don’t know other people’s perceptions of reality, and so we also don’t know what about our *own* perception of reality is outside the norm. Unless we happen to talk about it, which often never happens on topics like this.

  41. noyann says:

    How come some New Agey people say they can see auras around people? [ … ] they’re only around people and sometimes the colors seem meaningful. But add something about handwave handwave using a special kind of visual processing for other people handwave synaesthesia, and maybe it’s not totally outside the realm of possibility?

    I’d say they are a head-up display that brings a gut feeling into awareness.

    Actual content (“this person has communications issues”) was learned through experience (observed body language, eg a constriction or rigidity in certain areas; maybe even smell and pheromones). It is subconsciously stored in one’s own body (tonus imitation, one’s own reactive tensing/relaxing, bowel constriction, etc.) and actualized (read, similar to Gendlin’s ‘felt sense’) on encountering similar situations/persons as during learning. A heuristic related to what Gigerenzer describes. The weird coding of the output (EDIT: “there is a darkish brownish cloud around his upper chest and throat”) is due to culture and upbringing, imo.

    The interesting part is how and where this gets fed into visual processing. Given that we can map feelings into words, gestures, or music, this aura-coding of a gut feeling is likely to take place high up in the processing chain, far away from the retina.

  42. Aftagley says:

    I just read through the post and most of the comments below. Does anyone else find this whole topic really, really frightening?

    I don’t know why, but the idea that there’s just natural variation in a significant percentage of people’s experience of reality is a fundamentally terrifying idea to me.

    • FLWAB says:

      If perceived reality is not shared, that means many or most of us aren’t perceiving reality as it actually is. Which means you may not be perceiving reality as it actually is. The more people who report variations, the more likely your own perception is skewed. And if you have a certain kind of personality, that is terrifying. If you can’t perceive the world correctly how can you understand it? If you can’t understand it, then how could you ever be safe?

      • Aftagley says:

        All of those things and also – if there isn’t a fundamental reality that we can all come together to agree on, is continuous conflict inevitable?

      • Dino says:

        I vaguely recall reading of a philosophy claiming that there is no

        reality as it actually is

        and that everyone creates their own version of reality from their perceptions & whatever. I don’t agree, I think there is one “real” reality, and each individual’s version matches it more or less. In this case, the naive assumption would be that more accurate matching would be better for the individual, but I suspect there are exceptions.

    • bullseye says:

      I read your long reply to a comment above, and I get the impression that your mind is very different from mine. But I also get the impression that you’re perceiving the same reality that I am.

    • Dino says:

      the idea that there’s just natural variation in a significant percentage of people’s experience of reality is a fundamentally terrifying idea to me

      I find it more sobering than terrifying, but it is certainly something valuable to learn. I suspect most people don’t know it.

  43. Walliserops says:

    I don’t know if this is related, but about a decade back I was seriously into danmaku games, and after a few weeks of play I started seeing small particles moving in uniform patterns for a couple months. I could see them with eyes open or closed, and loose spirals were the most common pattern. This was also the only time I saw floaters.

    I guess my visual system got trained on tracking small moving objects and started to interpret everything under that lens. Does anyone else have similar experiences?

  44. Elementaldex says:

    Tossing in a datapoint/anecdote. I have never used any illegal or significantly mind altering drugs (Benadryl might be the most?). I do however have a degenerative corneal disease and the image on the left is a lot like what my vision looks like. No rainbow colors but doubling objects and bright halos are both common. I also frequently see geometric patterns in things like carpet, I have always thought this was because my vision is quite bad and my brain tries to fill in blanks with sometimes obviously wrong pattern matching.

    So I get most of the symptoms you are looking for while having a very different source than you are expecting. Some portion of the population will be like me. Maybe HPPD correlates with bad vision, or astigmatism, or some other visual deficit.

    • FLWAB says:

      You may be on to something. I am extremely nearsighted. I wonder if other commenters who have reported mild visual hallucinations in this thread who also haven’t taken hallucinogens might also have bad eyesight?

      • Taleuntum says:

        I have bad eyesight, I can’t recognize people on the street or watch TV comfortably from the couch without glasses. To my knowledge I don’t have any special conditions just simple bad eyesight. Though I haven’t been near an eye-doctor since 7 years ago, so I can’t be sure.

        I think it is unlikely that this would have caused the moving/wiggling of the pavement, as I was looking directly down which wasn’t the distance I have problem with: I can read without glasses comfortably.

    • Majuscule says:

      This is a great point. Any deeper analysis of this question should probably include multiple questions about the person’s actual eyesight.

  45. Jan_Rzymkowski says:

    My working hypothesis is that experiencing LSD trip simply make you more perceptive about all the inner workings of the computational part of the vision (biological computer vision).

  46. Nathan Leveille says:

    Long time reader, first time commenter, greetings and glad tidings to you all. Asperger’ s here.

    Scott, speaking as a person who for the last four years and counting has been addicted to dextromethorphan (no shortage of pharmacy chain locations here in New York and I’m unwelcome in many of them) my experience here may help someone. (When I show up at a new location and the favored brands are already sold out, I know there are others.)

    In September 2015, deep into a years long low level depression, I took a bad word of advice from friends on the internet and decided to experiment with Robitussin. The first high was nothing too special looking back but obviously, at the time, since I had drank plenty and used cannabis from time to time but had never been in an altered state of mind rather than just elevated mood. I could finally think clearly, see things the way others must be seeing them in order for their words and actions to make sense, music actially sounded enjoyable, small things like that on the first few occasions.

    Forward from there it progressed from one night s a week to two nights a week to daily use to landing in the ER for the first of five times, losing my retail job, getting and losing another retail job, running away from home twice, the secobd tine successfully, hence my writing this from a homeless shelter in Bushwick and not from my room in Rhode Island where I had lived for nine years. As the trips got longer abd bigger I began to crave certain familiar visual effects, for instance the way every object in my field of vision was actually a face that seemed to bear some particular expression i.e. the laundry basket looks the same but my brain reads the holes in the sides as numerous eyes, or my fingertips would look like they had a personality, things would grow and shrink, the fan in the bathroom would play the music I had just paused laying in bed. One night I spent two hours trying to remove evidence of vomit on the floor only to discover it was a stray piece of food on the carpet, all those sorts of things.

    When I was ib total dissociation a la ketamine my expefiences included being in the presence of divinity or divinities, having an alien race, which has just abducted me, subject me to a procedure where they pushed something like a steel beam through my field of vision but it was actually the delivery of Pure Truth, being trapped in an infinite time loop, the city speaking to me repeating the mantra “And this is what death feels like!), rock bottom in this regard being March 2017 when I tried to alert an entire subway platform to the imminent suicide bombing and landed myself in a psych ward for five days.

    Long story short I’m active in 12-step recovery and have been for years. Still using DXM to this day but for a long time it’s been just pills to the point where it basically looks like alcoholism, needing the substance to achieve the baseline neurotransmitter levels for everyday functioning.

    (I am in ongoing mental health treatment and satisfied with that treatment. No advice necessary.)

    I bring all this up, first of all, just because I’m glad I’m never going back to the land of bad trips, but also in the hopes that if anyone reading this thinks they may also have a problem do contact me.

    I’ve been typing forever this comment must go in about five different directions, but in response to the topic of discussion, I did not experience any hallucinations when I walked away from psychedelic dosages.

  47. TheRadicalModerate says:

    This probably goes without saying, but any persistent visual disturbance can be a symptom of a number of serious ophthalmic or neurological conditions. If you see wavy lines that should be straight, or if the faces you look at appear to be bad Picasso paintings, it’s time to go see an ophthalmologist ASAP.

    I had a macular hole (a retinal detachment in the center of the visual field, instead of the edges) last year, and I remember thinking that this looked just like what I saw when I dropped acid in college. It was considerably less fun, especially the part where you’re mostly face-down for a couple of weeks after the vitrectomy.

  48. jhertzlinger says:

    What would be the effects of a drug that strengthened priors?

  49. Yosarian2 says:

    If I pay attention I can usually see a sharp, bright outline around people’s skin that stands out, and really only around humans. I don’t know if that’s what other people mean when they say they see auras, but I think it’s at least a weak version of it. I’ve never used drugs.

    Not sure what causes it. I’ve speculated it might be a perception thing where my brain is highlighting humans and human faces for me because it thinks those are important. When I was younger I though there was a spiritualist woo meaning, but I don’t anymore. I can still see them though.

  50. Kilerpoyo says:

    Have you heard about Visual Snow Syndrome? https://www.visualsnowinitiative.org/

  51. toobes says:

    I just wanted to share some personal experiences related to HPPD that may give a different perspective to its causes.

    I went through a health crisis a few years ago and it took me a lot of self experimentation to figure it out. Through a lot of trial and error, guided by my background in science and a focus on gut health, I was eventually able to get better. Along the way I acquired some HPPD symptoms (visual snow, light trails, etc) and monitoring them proved helpful in evaluating the interventions I attempted b/c those symptoms were easy to identify and quick to react — I could literally see the effects.

    I found these symptoms got worse when my inflammation was high, especially when I was exposed to fungal antigens (such as after taking fluconazole, or anti-microbial herbs, especially after consuming sugar). They also got worse when I was tired, stressed, cheated on my AIP diet (a stricter version of paleo), etc. Taking anti-inflammatory herbs, CBD oil, THC, all helped reduce the symptoms [side note: but if I took too much of them for too many days in a row, it seemed to calm my immune system too much and allowed overgrowth in my gut — my hypothesis is that this could be a cause for many symptoms chronic marijuana users face]

    I agree that HPPD is likely to be caused by psychedelics sometimes, not just by directly affecting neurons, but also sometimes by affecting the immune system. Additionally, visual snow and trails are often caused by other things (check out the VS forums for many other examples), and perhaps taking psychedelics helps people notice them for the first time.

  52. safrazine says:

    I have never taken psychedelics.

    As long as I can remember, corners/right angles have wiggled back and forth. This scared me as a child because I knew they weren’t supposed to wiggle, and I didn’t tell anyone because I thought it meant there was something wrong with me. I thought maybe there was something wrong with how I learned to see? I looked at them often to try to figure it out. Not sure if this contributed to the below.

    I have always seen the visual snow. Thought this was normal sight. Do other people see totally clearly???

    Later I developed the ability to see changing/kaleidoscopic geometric patterns, “breathing” objects when I look at them, and color “auras” whet i look at things. I have assumed this was due to a meditative process though I haven’t really formally pursued meditation, I think I have just become very aware of my perception and when that happens weird perceptions start to occur. I am able to control the hallucinations to an extent. I often do it when i’m bored. I do have Synesthesia but usually just associative (projective when I am VERY tired only). Not a very “woo” – y person but score very high on openness to experience.

    • toobes says:

      Do you notice if different things can increase/decrease your visual snow and other effects? I left the comment just previous to yours and definitely notice a connection in my visuals to my inflammation levels.