It has no brain, no neurons, and no central control — yet a single-celled slime mold can navigate mazes, remember, and rebuild the Tokyo rail network from scratch in a petri dish. Meet Physarum polycephalum, the organism forcing scientists to redefine what intelligence even is.
Artist Heather Barnett co-creates with slime mold and shows it making decisions in real time. The perfect, mind-bending entry point to the whole rabbit hole.
The organism itself: a giant single cell with thousands of nuclei that behaves like a colony. Everything else in this rabbit hole radiates out from this creature.
Researchers placed oat flakes where cities sit around Tokyo. The mold grew a network nearly identical to the rail system engineers spent decades optimizing.
The original 2010 Science paper explained: how a brainless blob produced a fault-tolerant, cost-efficient network — and the algorithm engineers derived from it.
Time-lapse footage of the mold pulsing, branching, and solving problems. Watching it move is the moment the word "intelligence" starts to feel unavoidable.
It exhibits habituation — a basic form of learning — with no neurons at all. This Aeon essay asks where memory can possibly live in a body that is one cell.
NOVA's accessible tour of the decision-making, maze-solving, and food-ranking experiments — the science that made slime mold a genuine cognition research subject.