Unusual Experiences
created: 2024.05.19. 10:03 · modified: 2025.02.21. 05:47 · license

Unusual experiences that happen now and then. Some are so minor and personal that I forget them before I get around to asking anyone about them or looking them up. I have a few of those.

Most of the time, I forget them and move on. But every once in a while, I manage to ask someone else before I forget, or find something describing a similar experience. When I discover that other people have experienced it too—and that it even has an academic name—I feel a tremendous rush of excitement.

Below is a list of things I’ve discovered that way. I’ve put the rarer experiences, and those that mean more to me personally, toward the end. I’ll keep adding new discoveries even after finishing the first draft. In fact, the reason I’m finally turning notes I started gathering in May into this post today (December 16, 2024) is that I just learned the name for a particular experience I describe below: the Baader–Meinhof phenomenon.

*As I write, all sorts of psychological phenomena, such as déjà vu, keep coming to mind. I’ll leave out the ones that are already widely known.

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Chronostasis
Phosphenes
Multiplexed display break-up
Semantic satiation
Photic sneeze reflex
Baader–Meinhof phenomenon
Other experiences

The list

Chronostasis

Chronostasis, a.k.a. Stopped-Clock Illusion

The sensation that the first moment of a new event or action stretches out in time when the brain registers the event or is called upon to perform the action.

When I was little, if I suddenly looked at a clock after looking at something else, the second hand seemed to stop for a moment. Unless it has a sweeping seconds movement, a clock’s second hand does, of course, stop between jumps. But the pause seemed temporarily longer than usual. The following seconds passed at their normal pace. I used to imagine that the clock had frozen in surprise at my gaze?! Even then, I knew it was a silly thought.

Chronostasis is the broader phenomenon that keeps the same cause-and-effect pattern—“perceiving a new sensation → feeling as though time has slowed”—but applies it to the senses in general. Apparently it can occur with hearing and touch as well. Still, the clock’s second hand must be a common way to notice it: Wikipedia gives the “stopped-clock illusion” as a representative example of chronostasis.

The mechanism behind it is a bit complicated, so I’m moving on without claiming to understand it.

Phosphenes

Phosphene

A momentary sensation of light produced when the retina is physically stimulated by something other than light.

When I close my eyes, I see what look like scattered dots in the darkness. I can’t quite tell what color they are. They seem red, then maybe blue, then green again. There are more of them when I put pressure on my eyes—say, when I press my eyelids because my eyes ache, or rest my head on a desk with my forearm pressing against them. The dots also seem to drift like waves as my gaze moves through the darkness.

As a child, the dots reminded me of stars in space, and I enjoyed pressing on my eyelids to feel as though I were traveling through the universe. I probably shouldn’t have done that. The sources below explain that this phenomenon, called a phosphene, occurs when pressure on the eye stimulates visual cells much as light does, creating the illusion of seeing something. None of them, though, quite captures my experience. What stands out to me is that

dots or blotches are scattered irregularly;
their colors seem to change or are hard to identify precisely; and
they slowly drift away from or toward my gaze.

If I get the chance, I’d like to make my own visualization of it.

Multiplexed display break-up

Multiplexed Display Break-up

The phenomenon in which characters on a seven-segment display or similar screen appear to wobble when you look at them while chewing.

This isn’t a formally defined term; I borrowed the wording of Wikipedia’s description as a name for it.

Just as the description says, if I look at a digital display while chewing something, its characters seem to dance and wobble. But this doesn’t happen with text on every screen—only on seven-segment displays and similar types.

On these displays, only one light (or segment) is actually lit at a given instant. The characters appear whole because of the persistence of our vision. A display that works this way is called a multiplexed display. Wikipedia explains that the momentary shift in our viewpoint caused by chewing can disrupt the apparent alignment of segments even within a single character, making it seem to wobble.

Semantic satiation

Semantic Satiation

The phenomenon in which repeating a word or phrase temporarily makes it lose its meaning.

The Wikipedia article focuses on auditory repetition, but I’ve never experienced it through hearing—only through sight. A word I was reading or writing would suddenly feel unfamiliar. I hadn’t forgotten what it meant, but for some reason it seemed strange. This often happened when a word was repeated, though I remember it happening without repetition too.

I had this experience often through my teens, but hardly ever after becoming an adult. I suspect that’s because I no longer do the intensive repetition I once used to memorize new words.

It’s commonly misidentified as “Gestalt collapse,” and some say the two terms refer to similar but distinct phenomena. I’m not sure what’s correct.

Photic sneeze reflex

Photic Sneeze Reflex, a.k.a. ACHOO*
*Autosomal dominant Compelling Helio-Ophthalmic Outburst syndrome
(an inherited condition that causes sudden sneezing in response to sunlight)

A medical condition that causes sneezing in response to stimuli such as looking at bright light or receiving an injection around the eye.

Apparently 18–35% of people have it, and I’m one of them. If I step outdoors after being inside on a bright, sunny day and look toward the sun, I’m very likely to sneeze. Wikipedia’s description fits me closely: it usually causes 1–10 sneezes (about three for me), followed by a refractory period of up to 24 hours. Without that refractory period, my Paleolithic ancestors might have sneezed right through the sight of a predator in front of them and been eaten...

I haven’t experienced sneezing from an injection yet, though I can somehow imagine it happening.

As an aside, I also sneeze when I eat dark chocolate. Sunlight makes me sneeze sometimes but not always; dark chocolate does so almost 100% of the time. Again, after up to three achoos, I don’t sneeze anymore, even if I keep eating chocolate.

I find it kind of cute that the researchers forced together such an unnatural combination of words just to make the acronym ACHOO. Haha.

Baader–Meinhof phenomenon

Baader-Meinhof Phenomenon, a.k.a. frequency/recency illusion.

The phenomenon in which something seems to appear more often around you after you learn about it.

These days (December 2024), I’m using NASA’s trajectory-design tool, General Mission Analysis Tool (GMAT), for a project at the lab. There are so many settings to work with, and so much background knowledge needed to use it properly, that I’m still learning it step by step rather than putting it to full use.

Today I was working through one of the more advanced tutorials included with the program. The goal was to adjust the speed of a spacecraft departing Earth so that it would enter the desired orbit around Mars. The instructions first told me to name the spacecraft “MAVEN” in the program. MAVEN? I’d never heard the name before. I briefly wondered where it came from but kept going without looking it up.

That evening, after work, I was browsing Instagram. I went to my list of liked reels to find one I’d seen before, then got sucked into watching the list all over again. One reel caught my eye: it showed a round celestial body with what looked like a purple filter over its left half. I opened it and saw that NASA had posted it. I couldn’t remember liking it, much less what the video meant, so I opened the caption. And there it was: MAVEN. MAVEN is a Mars orbiter sent by NASA, and the video showed data from its ultraviolet instrument overlaid on an image of Mars.

What?! I’d encountered a word for the first time in my life, then come across it again just hours later by a completely different route? It gave me goosebumps.

It’s hard not to be surprised when something like this happens, but it happens more often than you might think. I remember several specific examples. I didn’t even know Gwangju Bank existed until I saw its headquarters on a visit to Gwangju. Then, just a few days later, I suddenly noticed a Gwangju Bank branch on a street in Yangjae I must have passed many times before.

I think this happened even more often when I was little, when so much of what I saw and heard was new to me.

My own interpretation largely matches the academic one: an astronomical amount of information is always around me, some of which I can understand and some of which I can’t. Only after learning a new fact do I begin to take in the surrounding information it helps me understand. That sometimes leaves me afraid to think how much information I usually miss (as I’ve mentioned before in another post).

Other experiences

These are unusual experiences I’ve had several times but haven’t found academic sources for. I made up the names myself.

Brain indexing error

A phenomenon in which I think I know something, but the harder I try to recall it, the more even the knowledge I thought I had seems to disappear, until I can’t retrieve it at all. This happened occasionally while I was growing up, but it doesn’t seem to happen much these days. Could it be a relic of a still-developing brain?

Once, I tried to understand it by analogy with something I learned in my undergraduate computer science courses. In computer storage, some parts hold the information itself, while a separate index identifies what information is stored where. When you delete a file, the computer’s file system deletes only the index entry. The pointer to the information is gone, but the information itself isn’t actually erased until new information overwrites it. What if an error did the reverse, leaving the index intact but erasing the information it points to? The user wouldn’t notice anything wrong from the index alone; only when they tried to access the information would they realize something was amiss. I wondered whether my experience could be explained if the brain had a mechanism like a computer’s index for managing information efficiently.

Repeating thoughts

The phenomenon in which one arbitrary thought, unrelated to the task at hand, keeps recurring during intense physical or mental work.

I experience this only during school exams—only when I’m using my brain so intensely that, even after the exam is over and I’ve gone home to take a nap, my head is still racing and I can’t fall asleep. Ordinary effort isn’t enough to bring it on. It’s happened several times, but I’ve always been so busy taking the exam that I can’t remember any of the specific thoughts. I do remember that they had nothing to do with the exam and that, each time, the same single thought kept recurring.

Because it only happened when I was that overwhelmed, I never had the chance to consider whether it was unusual or wonder if anyone else had experienced it. Then I saw the following scene in a webtoon and finally realized I wasn’t the only one.