Intelligence in Nature - Jeremy Narby [41]
I said I understood the term smart to mean flexible and quick when referring to materials.
âAh, okay, so this word is more appropriate for our study,â he said. âFlexibility and adaptability.â He wrote both terms under the smartness list.
This prompted me to mention the definition of intelligence used by Anthony Trewavas when referring to plants: âadaptively variable behavior during the lifetime of the individual.â
âYes, yes, yes,â he said. âAll kinds of organisms have such abilities, adaptability and flexibility. This is true, I believe.â He contrasted these abilities to awareness and mind and went on to discuss information processing in biological systems. He wrote the word unconsciousness on the board and said that most information processing in humans occurs at the unconscious level. âSo awareness is the small tip of a large mountain. In this sense, all kinds of organisms have a sort of unconscious level of information processing. This ability is very high, higher than we expect.â
Nakagaki pulled out a round, plastic dish and handed it to me. It contained the original 3-by-3-centimeter maze in which he and his colleagues had tested the slime mold. It consisted of a negative of the maze cut from a plastic film and superimposed on an agar plate. As true slime molds dislike dry surfaces, they tend to crawl only on the wet, gelatinous agar plate, which the plastic film does not cover.
Then he turned to his computer and showed us some video images of the experiment. First one sees Nakagaki cutting about thirty small pieces from the growing tip of a living slime mold and placing them throughout the maze. As true slime molds move at a speed of about half an inch an hour, it takes a time-lapse camera to reveal their movements. A two-minute sequence concentrating several hours of action shows the bits of slime spreading themselves along the mazeâs corridors and blending into one another. They become a single organism, one giant cell covering all available space within the maze. Nakagaki then places the slime moldâs favorite food, oatmeal, at the start and end points of the maze. Waves start rippling across the yellowish body of the slime mold, emanating from around the oatmeal and splashing down the mazeâs corridors. The flat mass of yellow jelly that makes up the slime moldâs body begins to develop veins that run through the maze. The slime mold ends up withdrawing from blind alleys, avoiding detours, and reducing itself down to a single yellow vein connecting the two food sources by the most direct route.
After seeing these images, I asked Nakagaki if he could show us a living slime mold. He accompanied us out of his office and across the corridor into the storage room for unicellular organisms. The room itself was painted in drab yellow and contained several refrigerators. He opened one and brought out a foot-long plastic container half filled with a bright yellow slime mold. On close inspection, the giant unicellular creature had a solid texture, like mashed potatoes. Nakagaki explained that when a true slime mold lacks water, it goes into a dormant phase during which it becomes dry and can be stored almost indefinitely.
I asked how the idea of putting a true slime mold into a maze first came to him. He said that several years previously, one of his jobs was to feed the laboratoryâs slime molds. He usually gave them oat flakes. One day he noticed that if he sprinkled the oat flakes randomly on top of a slime mold, it would form tubes connecting the food sources, and that the tubes were connected to one another in a such a way that the organism derived the maximum amount of nutrients in the minimum amount of time. As Nakagaki has training in mathematics, he began trying âto clarify the smartness of that tube network.â He said the point of the maze was to test the expression of that smartness.
We headed