Snakes, and many reptiles, have a split tongue because they smell with their tongue, and the two-tongues let them know which direction the smell is coming from. Humans, however, have split tongues because they want to. Tongue-splitting is a form of body modification.
In other news:
Jun 2017, phys.org
“These synthetic "tongues" can highlight similarities between whiskies, but they can't identify an unknown whisky from scratch, he says, "You start with a sample that you know is the real McCoy. Then you look at another sample, and you can say whether it's the same sample or it's not." In other words, these tongues would be great for spotting counterfeits of expensive luxury whiskies.”
Note that this synthetic tongue cannot taste like we do. Well, first of all, note that taste and smell are very similar; Humans don’t smell with our tongues like snakes do, but most of what we “taste” is actually perceived by our nose. Nonetheless, this synthetic whisky tongue still does not work the same way as our perceptive apparatus. This tongue can only identify pre-determined patterns. You give it one flavor profile to ‘sense,’ and ask whether a new sample matches that or not. You can’t give it any old thing and ask “what is this?”
Perhaps the most amazing thing about our olfactory sensory apparatus is that it begins as a blank slate, with no hardwiring for any smells whatsoever. Everything we smell, and everything we can identify, we learn. If we want this synthetic whisky tongue to be able to identify a whisky from scratch, we need it to grow up like a little human, learning every single smell from scratch, just like us.
This is the same old story with all of these reverse-engineered smell-and-taste organs. They cannot be used to sense the way we do, where they are able to identify any combination of hundreds of thousands chemicals. Instead, they are given one job, to smell one thing, and they either smell it or they don’t. It’s like making an eye that is only for seeing the color red. Red or no red. It doesn’t know the Pantone catalog, only that one red. Instead of choosing from the infinite answers to the question “what do you smell,” these prostheses can only choose from two possible answers, yes and no.
To program a truly synthetic tongue, or better, a synthetic nose, is still very, very far beyond our capacity. In the meantime, things will progress as they do; one piece at a time, dividing the human capacity for information-gathering into myriad discrete operations, and recreating ourselves through the fractured image of technology.
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