Friday, October 20, 2017

Chemotaxis vs Infotaxis

Hey, you dropped something. The back of your earring, it’s gotta be somewhere in this shaggy carpet. Hands and knees you search intently in a one foot radius of the spot you think it should be. After some time, your search-space widens, you move over a few feet, and begin again, very concentrated.

This is the foraging pattern. In searching for blackberries, you stop at this bush and look and look and look, and then you go to another bush altogether, and so on. It’s a lot like fractals, and a lot like Antonio Barabasi’s Bursts. The pattern of searching, or foraging, occurs in clusters. And the search-pattern within the clusters is repeated in the larger pattern of the clusters relative to each other.

Taken to its conceptual limit, we observe the common roundworm, neuropop celebrity extraordinaire, C. Elegans. If a worm thinks there is food somewhere, it will perform an intensive search in that local area, until 15 minutes are up, at which time they will literally make less turns, and explore a wider, more global area.

Humans usually rely on vision to search for things. Worms don’t; it’s much more effective for them to follow their nose. In this case, their search is informed by a chemical gradient. As they search for the source of an odor, they notice whether their target scent is getting closer or further. This is the chemical gradient, and it, in a sense, decides for the worm. All the worm needs is a memory big enough to store the last sniff, and compare it against the current one, and it can decide whether to go ahead, or to turn.

In reality, the worm has more than just a one-sniff memory capacity. It is in fact creating a gradient map of all the places it searches, as it searches. The seemingly infinite wonder that is the human memory begins with this basic foundation. And it is for this reason that smell and memory are such an intimate, indivisible pair.

What happens when the worm has no chemical gradient to help it decide? This is where it switches from chemotaxis to infotaxis. And I bring this up simply as an excuse to use the word infotaxis, because I really like it. Also, I was thinking about the future, and the idea of infotax, which, considering the advance of Bitcoin, might not be too far off. And then, there’s info-taxis, like taxi-the-car, which I can’t even imagine what that is or what it will do, but it will probably happen too.

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