A slime can solve a maze
The plasmodium of Physarum polycephalum finds the shortest path through a maze by growing toward food and letting dead ends starve.
Established2 min read
Nakagaki, Yamada, and Tóth laid the slime across a maze and put oat flakes at two exits. The organism spread, then withdrew from corridors that did not connect the food. What remained was a tube along a shortest path. The computation is growth and retreat, guided by nutrient gradients and the cost of maintaining a vein.
Later work showed the same trick approximating efficient transport networks. It is not thinking in the animal sense. It is a body that is also a search algorithm, and the algorithm works.
Caveats
- The slime does not ‘know’ the maze. It explores all of it and abandons what does not pay.
- Results depend on the geometry and the food. It is a reproducible behaviour, not a party trick that works once.
Sources
- 1Nakagaki T., Yamada H., Tóth Á.. Maze-solving by an Amoeboid Organism. Nature 407, 2000.