[Errancer]

So if this is what we would consider "hallucinations" then sure I experienced all this and more. One of the more interesting experiences for me is when I try to cook food on acid. On day to day basis I am quite good cook and I can reliably judge how well done something is but on LSD all those abilities simply disappear. I can't tell if the meat on the pan is done or not without thermometer. But I think reducing hallucinations to distortions doesn't fully capture what is going on. LSD affects the mechanism of active perception as well as the passive perception. I think when we talk of hallucination then this is the area people have in mind and what is important hallucination is one of the least interesting ways acid affect active perception. What I mean by active perception as contrasted with passive one is that all things you mentioned are passive perceptions. But our mind does not only recognises objects in the world but it is also participating in constructing new categories which establish new objects. For further reference the key-word is "The myth of the given" but what I want to point here is that this ability of the mind to put sense data under categories is affected with LSD in a incredibly interesting way. This is why hallucinations as perception of things which completely don't exist are so difficult to have and you either need to have a "special type of soul" or take such a large dose that you no longer operate on external sense data since they are so distorted.

[IIAOPSW]

You're trying to clarify the neat categories you'd like to draw between layers of abstraction. As if to say "oh absolutely it effects the raw input (active perception), and maybe a tiny bit of that subconscious processing one step above there (passive perception), but I've never had it leak all the way up the chain to the seat of consciousness itself (hallucination)". Which is fine I suppose though I don't see what this structure adds.

You're correct that my immediate tests are all at the lowest level of abstraction. I picked them simply because they are the types of distortions which manifest first and quickest and least ambiguously. If you or anyone else isn't sure if the acid has kicked in, or is uncertain that they are experiencing any changes, these are the debugging tools. At higher levels of abstraction you get things like streamers, transposing of near identical objects, and sometimes even weird face distortions.

The taste thing is quite curious to me. Have you considered setting up an experiment to try and pin down exactly which flavors are distorted and how?

[Errancer]

If we are looking for tests whenever we are tripping or not then sure, what you described is definitely the way to go. The categories I am drawing are not important for that. I make them to on the one hand tell people that they probably won't lose their consciousness and on the other that there will happen something more than simple "eye-filter". This middle step I find the most interesting, possibly dangerous and missing from wide-culture discussion so I want to pin it down. Especially that it is interesting feature of the mind independently of psychedelics. An experiment with tastes could be interesting but lately I simply avoid eating while tripping since I feel my stomach too vividly. Once I had to eat plain rice for some time after the trip since everything else was too overwhelming.

[IIAOPSW]

It was probably in Psychedelic Information Theory where I read the closest to the missing middle you are looking for. The visual system, being the most complex, is the most fragile and thus any perturbation is likely to manifest as neat geometry first. Most commonly this takes the shape of one of the form constants, which is pretty easy to explain as those patterns are directly encoded in the first few layers just after the optical nerve. So you randomly poke any neuron there, you'll get those shapes. Even waking up tired can cause it (hypnogognia). The next layer of distortion up has to do with the main loop structure (hypothalmus loop? its been a while my memory sucks). These sorts of distortions you might miscategorize as the first kind since they are still most often just "vfx magic eye filter". But they aren't so simple and in fact are distortions of a higher order of pattern recognition. I'm talking about effects such as a moving object appearing to be multiple places as though a strobe light is flickering. Or looking for a dot and suddenly seeing dots amplify everywhere in your view. By that point coherent speech is a bit hard to manage and focus is usually not forthcoming for any multi-step task. From there its pretty much a continuum on up to the point where understanding the difference between in your head or not also becomes a noisy signal. But that usually doesn't happen on acid. I get what you're after, I think a continuum of effect is a more apt concept.

Without eating per se, would you consider testing an assortment of tastes such as salt, sugar, whatever spices you have etc?