William Gray Walter created some of the world's first first electronic autonomous robots. Born in Kansas City, Missouri in 1910, at the age of five, he was taken to England and was educated at Westminster School and afterwards in King's College, Cambridge, in 1931. He failed to obtain a research fellowship in Cambridge and so turned to doing basic and applied neurophysiological research in hospitals, in London, from 1935 to 1939 and then at the Burden Neurological Institute in Bristol, from 1939 to 1970.
He also carried out research work in the United States, in the Soviet Union and in various other places in Europe. He married twice, and had two sons from his first marriage and one from the second. According to his eldest son, Nicolas Walter, "he was politically on the left, a communist fellow-traveller before the Second World War and an anarchist sympathiser after it." Throughout his life he was a pioneer in the field of cybernetics. In 1970 he suffered brain injury in a motor scooter accident. He died seven years later on May 6, 1977 without fully recovering.
Grey Walter's most famous work was his construction of some of the first electronic autonomous robots. He wanted to prove that rich connections between a small number of brain cells could give rise to very complex behaviors - essentially that the secret of how the brain worked lay in how it was wired up. His first robots, which he used to call Machina speculatrix and named Elmer and Elsie, were constructed between 1948 and 1949 and were often described as tortoises due to their shape and slow rate of movement - and because they 'taught us' about the secrets of organisation and life. The three-wheeled tortoise robots were capable of phototaxis, by which they could find their way to a recharging station when they ran low on battery power.
In one experiment he placed a light on the "nose" of a tortoise and watched as the robot observed itself in a mirror. "It began flickering," he wrote. "Twittering, and jigging like a clumsy Narcissus." Walter argued that if it were seen in an animal it "might be accepted as evidence of some degree of self-awareness."
One of the tortoises was modified, (given the pretend scientific name Machina docilis) and had added to its simple single celled "brain" one, then two conditional reflex circuits in which they could be taught simple behaviors similar to Ivan Pavlov's dogs. This tortoise was called CORA. One of these included being hit meant food whilst whistling means food, and when conditioned such a whistle by itself means being hit. When he added another circuit tuned to a whistle of another pitch, this could become whistle means being hit, whistle means food, this would make the animal become "afraid" whenever food was presented. Walter remedied this behaviour by severing the two additional circuits, and the tortoise reverted to being a Machina speculatrix. The conditioned reflex behaviour was later placed into a static desktop model, also known as CORA.
Later versions of Machina spectulatrix were exhibited at the Festival of Britain in 1951. Walter stressed the importance of using purely analogue electronics to simulate brain processes at a time when his contemporaries such as Alan Turing and John Von Neumann were all turning towards a view of mental processes in terms of digital computation. His work inspired subsequent generations of robotics researchers such as Rodney Brooks, Hans Moravec and Mark Tilden. Modern incarnations of Walter's turtles may be found in the form of BEAM robotics.
An original tortoise is on display in London UK in the Science Museum's Making the Modern World gallery. Recently, one was also replicated by Dr. Owen Holland, of the University of the West of England in 1995 - using some of the original parts. An original tortoise as seen at the Festival of Britain is in the collection of the Smithsonian Institution.