This is a fundamental difference between psychedelics such as psilocybin and deliriants like datura. Usually, with psychedelics, you know that what you are seeing is not real, or at least, that it is not normal. With deliriants, even if you know exactly what you took and the effect it has, the crazy things you are seeing feel real and perfectly normal until the effect wears off.

What make me feel goes to the psychedelic side is that description talk about something wonderful, or at least worthy of attention. If it was a hallucination in its purest sense, the presence of little people would be no weirder than that of a cat or a dog.

But the fact that it is generally considered unpleasant and not used for recreational or spiritual purposes is more of a deliriant thing.

More info about what metabolites may be involved.

I sent the Vice article to my girlfriend and she had a good question and wondered if the mice treated with it see even smaller little mice.

I guess you could call it something like, "system-limited emergence," in the sense that different systems can have similar outputs if they are structured the same way.

In other words, the idea is that differing groups of people don't see elves because they are all accessing some hidden reality full of elves, but rather because the drug induces the same reaction in a human body, no matter its location.

This maybe seems obvious for mushrooms or other substances, but I think the same concept applies to other phenomena too: the spread of ideas, political actions, etc. Or maybe I've just been watching too much Ghost in the Shell.