Between 1948 and 1949, the neurophysiologist William Grey Walter built what are widely regarded as some of the first electronic autonomous robots. He called them Machina speculatrix, and their best-known examples were named Elmer and Elsie. Often described as “tortoises” for their shells and slow, deliberate movement, the three-wheeled machines used simple analog electronics - just two valves (vacuum tubes) - to wander, steer toward light, and back away from obstacles.
Their most striking behavior was self-sufficiency: as Walter’s design showed, the tortoises “were capable of phototaxis, by which they could find their way to a recharging station when they ran low on battery power.” From only a few components Walter coaxed surprisingly lifelike, goal-seeking behavior. He even put a light on a tortoise’s nose and let it see itself in a mirror, observing it begin “flickering, twittering, and jigging,” which he half-seriously offered as a hint of self-awareness.
Walter’s tortoises were a cybernetics-era demonstration that complex behavior can emerge from simple sensorimotor loops rather than from explicit internal models or symbolic reasoning. That idea echoed decades later in Rodney Brooks’s behavior-based robotics, and Walter’s work is cited as an inspiration to roboticists including Brooks, Hans Moravec, and Mark Tilden.