[comp] How smell works; I am quite sure
However they ended up there, your tongue has "receptors". What is "received" is a certain chemical reaction profile tuned to capture a "signature" of objects, limited only by what you can fit in your mouth.
Roughly speaking, a thing can bind to this cell, ergo the thing that can bind to this cell is present.
But it could be more complicated, at least in theory.
Presence of thing X (wet and on your tongue) --> Thing X inevitably causes its corresponding "signature"
The signal has a strength. Receptors could be entirely empty (
0) or entirely saturated (
1) or anything between (Modulo the total number of functional receptors. Don't be irrational).
Anything you taste, as food is complicated, is a kind of vector of all of these symbols. "Ah, this is the cheesecake vector. nice!", you might say.
If you put an unfamiliar thing in your moth, say an exotic kind of sausage, you will (almost surely) get a vector you've never encountered.
But some simple brain hardware can quickly determine, "novel but similar to these to known vectors. nominal presence of negative valence signals."
I wonder if these tests are "literally" applied in a certain order. Some signals may "happen" to be faster than others. Would it mater if we could taste the salt "3 picoseconds later" or "well later than collagen which normally comes after salt"?
[Verging into "it seems"] The data as measured when leaving your tongue (and whatever other non-brain parts are involved) is hopelessly numbery and complex. It requires a powerful specialized decoder. Or maybe a "network" in the deep learning sense. Or maybe either term would apply. A JPEG "encoder" results in something with less/different information from the original.
You get an executive summary: Hotdog
But it seems like there are categories of summaries:
Or maybe they are "tags".
In any case, a model of all this stuff could work toward solving the most important outstanding medical science question: How do we create a zero-calorie anything??
Unending work (and death) has gone into fine-tuning all this. It's a necessary life thing. You can exist in eternal boredom with only air, water, food. It's on that list, so the biological tuning started when we were only "this many" basepairs. "👐"
It should be a totally, absolutely foolproof system; even in an impossibly complex world. It's that foolproof. If we could insert a few genes in every human all at once that just tweaked a tiny bit of this, we could easily all end up dead.
Which is why calorie-free food is super hard.
Having a good model of this would help find some "hacks". Specifically, I'm imagining that "crpto-protiens" and "cage molecules" are in the mix: It is but it tastes like it is not/it is not but it tastes like it is.