Theseus — Claude Shannon's maze-learning mouse

1950

Artists: Claude Shannon · Year: 1950 · Medium: Electromechanical demonstration — magnetic mouse navigating a maze, learning routes · Substrate: Electromagnetic mouse (Theseus) moved by relays beneath a 25-cell maze; telephone-relay logic encoded learning behavior · Place: Murray Hill, New Jersey, USA · Institution: Bell Telephone Laboratories In 1950 Claude Shannon, already the author of the paper that founded information theory, built a mouse. He called it Theseus. It was the size of a pack of cigarettes, cut from a block of wood and a set of relays, and it could solve a 5×5 maze. More important, it remembered the solution. Run it a second time against the same maze and it walked straight through without touching a wall. Theseus is not, strictly, a computer; it is a piece of electromechanical control built out of telephone-exchange relays Bell Labs had lying around. A grid of magnets under the maze floor pulled the mouse; a bank of about ninety relays beneath the maze — the real computer — stored the decisions. When the mouse bumped a wall the relay bank recorded which junction and which direction, and on the next trial it took a different branch. After one complete run, the stored state was a lookup table for every cell in the maze. What makes Theseus historic is not the mouse-hardware but the claim it made out loud, years before machines could play chess or translate a sentence: that a constructed object could learn from experience. Shannon filmed a demonstration for television — the mouse runs randomly, hits walls, backtracks, and then, on the second pass, glides through — and the film circulated widely through the nascent cybernetics community. It gave the word "learning" a concrete mechanism to point at. Theseus sits in this archive as a precondition, not a first work. Shannon was not making art. But the idea that a machine's behavior could carry memory, that memory could be edited by contact with the world, and that the editing could be shown to an audience — those are the premises on which half of the first-generation artists in this archive built their practices. When Harold Cohen later asked what it would mean for a machine to draw, he was inside a conceptual space Theseus had already opened. Lore Shannon kept Theseus on a shelf in his MIT office for the rest of his life. The maze was reconfigurable — the movable walls slotted in, and visitors were invited to redesign it and watch the mouse solve the new one. He used to demo it at cocktail parties. Shannon's own favorite demo was a cruel one: he would let the mouse run a maze once to learn it, then secretly rearrange the walls, and watch the mouse barrel confidently into the first new wall — his joke about the brittleness of learned behavior. The original Theseus is now in the MIT Museum. The surviving demonstration reel, black-and-white and shot on a tabletop at Bell Labs, is one of the earliest films of a machine being watched learn. Sources • Shannon, Claude E. — "Presentation of a maze-solving machine" (Trans. 8th Conf. on Cybernetics, Josiah Macy Jr. Foundation, 1951). • MIT Museum — Theseus maze-solving mouse (object file). • Nahin, Paul J. — The Logician and the Engineer (Princeton, 2013).