Robots, in one guise or another, had been suggested as far back as 1495, when Leonardo da Vinci created his mechanical knight robot. However, the first significant robot prototypes, built in 1948, were a pair of tortoiselike robots named Elmer and Elsie.
Created by United States-born neurophysiologist and inventor Dr. William Grey Walter (1910-1977), the tortoise robots were remarkable in their ability to mimic lifelike behavior. These experimental robots incorporated sensors for light and touch, as well as motors for propulsion and steering, and a two- vacuum tube (valve) analog "computer."
With the aid of simple circuitry, these electro-mechanical, three-wheeled robots were capable of phototaxis (an automatic movement toward or away from light), and could thus find their own way to a recharging station when they ran low on "food"—a precursor of the technique used in the popular Sony Aibo" robot dog some sixty years later. Using a combination of light-level and motor-power settings, four modes of operation were possible. This produced a variety of unique behavior patterns in the tortoises. In one experiment, Dr. Walter placed a light on the front of a tortoise and watched as the robot considered itself in a mirror.
Because of their speculative, exploratory tendencies, Dr. Walter called his tortoises "Machina Speculatrix." Designed to aid the study and testing of theories of behavior arising from neural interconnections, these small robots with reflexes were hugely influential in the birth and development of the sciences of cybernetics and robotics.
