Can you elaborate a bit? I don't remember hallucinating when growing up[1], so I'm interested what this would look like. I don't doubt that it may still be common without everyone experiencing it.

[1] Or ever, really, unless fever dreams when being really sick count. Though, without any reference point to compare to, they really seemed more like intense dreams.

I consider myself to be a very mentally-stable person, but I have encountered occasional hallucination-like experiences. They're very brief, and my brain seems to correct itself retroactively, which makes them somewhat difficult to notice. For example, a soft noise could be vividly interpreted as someone calling my name, but when it becomes apparent that this didn't happen, my brain files the experience as "probably misheard something", and my attention is immediately diverted. Supposedly smell hallucinations are pretty common too. These are hard to recall because they're so unremarkable. It's difficult to tell these things from common daily "mistakes", but is there really a difference except in effect size?

A classic one that many experience is thinking you see someone or something notable or scary in the dark, that turns out to be whatever ordinary thing is actually there.

Is that really a hallucination? Or is it your brain’s pattern recognizer making an incorrect guess and then quickly course-correcting when more data is present?

The surface boundary of what does or doesn't count as a hallucination isn't necessarily clear or well agreed upon.

> is it your brain’s pattern recognizer making an incorrect guess

This part is more or less an accurate explanation of a lot of hallucinations. Input misinterpreted and incorrectly "output" into consciousness.

I've had events in deep meditation where I hear things as though they were actually audible and not just a memory of sound or see things as though my eyes were seeing them and not visually remembering them.

They always scared me even though the audible events would be something simple like a "Hello!" or like, a bottle cap opening or a bit of music and the visual events would be like, a match striking or a bit of fire.

I am not sure what causes this transition of perception. Some people say its your brain releasing DMT, some say it's activation of your parasympatheic nervous system. I don't know for sure, but I don't think it is anything to be afraid of.

Yes, these are quite common. I believe persistent, full-on visual hallucinations tend to be rare among the general population, assuming you're sober and not sleep deprived or in a half-asleep state or in the process of waking up.

This, and similarly Déjà vu, both happen to me too, very occasionally. I definitely also see a correlation with times I'm significantly fatigued, for example after being awake for 20 hours during a multi-day fast.

The parent poster mentioned having taken LSD and later experiencing HPPD (hallucinogen-persisting perception disorder). Visual disturbances and distortions are often associated with both. In rare cases it can last for months or years, if the HPPD is severe.

Yeah, although I may have been too aware of my body's normal distortions, it was fairly typical HPPD from what I hear. Walls breathing, tile floors becoming 3d, constant visual snow layered on my vision. I'd say my thinking became somewhat more disorganized after the experience as well. I used to be a fairly fast reader and afterwards I had to slow down and also start re-reading more. I also had a fair amount of panic attacks, even ending up in the ER once when I was 18.