[dudefeliciano]

There is a similar effect related to Delirium Tremens, caused by extreme alcohol withdrawal. Apparently people across cultures report seeing the same "Hat Man" in their peripheral vision, who disappears when looked at directly, but everyone seems to report the same ominous feeling about him. Also there are reports of people seeing a bunch of spiders everywhere, when going through alcohol withdrawal.

[finghin]

The mind and body are always in sync somewhat, even when under great stress like that. Anticholinergics at high doses act almost mechanistically on the PNS to create the parasthesia/formication on/under one’s skin. I think the visual perception of the insects is in that case secondary to the tactile sensation.

That is quite characteristically distinct to the “endogenous” appearance of other figures when using serotonergics, that almost certainly arise from intra CNS activity

[jumpconc]

I wonder if people who have never seen or heard of hats will talk about a Hat Man.

[grvbck]

I'd bet my money on no. To my understanding, those hallucinations are basically brain-level disturbances in perception, where the brain does its best to fill in ambiguous activity with known objects. So I guess if you've never seen hats (or men), your brain would just interpret the signal as something different.

Extreme tangent but interesting (to me): people in different cultures experience voice hallucinations differently. In the west, "hearing voices" is often frightening because the voices are hostile. In other cultures, the voices are friendly!

https://news.stanford.edu/stories/2014/07/voices-culture-luh...

[gentooflux]

That's an interesting question, but the answer probably isn't worth the trauma you'd inflict on a child by intentionally raising them to be completely unaware of the existence of hats.

[ravenstine]

Those are also common hallucinations reported for recreational Benadryl dosages.

[phrotoma]

And extreme sleep deprivation.

[potsandpans]

I did a search for "Delirium Tremens hat man" and there were a couple of things about Benadryl and this post.

[dudefeliciano]

Hmm ok, I went down a youtube rabbit hole a while ago where people who experienced delirium tremens talked about it. But the sources online do seem to associate it more to benadryl and sleep deprivation, not sure if it's because extreme alcohol deprivation is less studied nowadays (I don't think any modern clinical study would allow someone to go cold turkey and possibly die just to confirm the existence of a hat man, but apparently these types of studies were done at the beginning of the last century)