William Grey Walter | |
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| Born | February 19, 1910 Kansas City, Missouri, United States |
| Died | May 6, 1977(1977-05-06) (aged 67) |
| Citizenship | United States (birthplace),United Kingdom[explain status] |
| Known for | Brain Wave,Delta wave,Alpha wave,Autonomous robot |
| Spouse | Vivian Dovey |
| Scientific career | |
| Fields | Robotics,neurophysiology |
William Grey Walter (February 19, 1910 – May 6, 1977) was anAmerican-bornBritishneurophysiologist,cybernetician androbotician.
Walter was born inKansas City,Missouri, United States, on 19 February 1910, the only child of Minerva Lucrezia (Margaret) Hardy (1879–1953), an American journalist, and Karl Wilhelm Walter (1880–1965), a British journalist who was working on theKansas CityStar at the time. His parents had met and married in Italy, and during the First World War the family moved to Britain. Walter's ancestry was German/British on his father's side, and American/British on his mother's side. He was brought toEngland in 1915, educated atWestminster School with an interest in classics and science, and enteredKing's College,Cambridge, in 1928. He achieved a third class in part one (1930) and a first class in physiology in part two of the natural sciences tripos (1931).[1]
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 theBurden Neurological Institute inBristol, from 1939 to 1970. He also carried out research work in theUnited States, in theSoviet Union and in various other places inEurope. He married twice, having two sons from his first marriage, and one from the second. According to his eldest son,Nicolas Walter, "he was politically on the left, acommunist fellow-traveller before theSecond World War and ananarchist sympathiser after it."[2]: 34–42 Throughout his life he was a pioneer in the field ofcybernetics. In 1970, he suffered a brain injury in a motor scooter accident.[3] He never fully recovered and died seven years later, on May 6, 1977.
As a young man, Walter was greatly influenced by the work of the Russian physiologistIvan Pavlov.[citation needed] He visited the lab ofHans Berger, who invented theelectroencephalograph, orEEG machine, for measuring electrical activity in the brain. Walter produced his own versions of Berger's machine with improved capabilities, which allowed it to detect a variety ofbrain wave types ranging from the high speedalpha waves to the slowdelta waves observed duringsleep.
In the 1930s, Walter made a number of discoveries using hisEEG machines at theBurden Neurological Institute inBristol.[4]: 60–83 He was the first to determine bytriangulation the surface location of the strongestalpha waves within theoccipital lobe (alpha waves originate from thethalamus deep within thebrain). Walter demonstrated the use ofdelta waves to locatebrain tumours or lesions responsible forepilepsy. He developed the first brain topography machine based onEEG, using an array of spiral-scanCRTs connected to high-gainamplifiers.
During theSecond World War, Walter worked on scanningradar technology andguided missiles, which may have influenced his subsequentalpha wave scanning hypothesis of brain activity.[5]
In the 1960s, Walter also went on to discover thecontingent negative variation (CNV) effect whereby a negative spike of electrical activity appears in thebrain half a second prior to a person being consciously aware of movements they were about to make.[6] Intriguingly, this effect brings into question the very notion ofconsciousness orfree will, and should be considered as part of a person's overallreaction time to events.
Walter's experiments withstroboscopic light, described inThe Living Brain,[7] inspired the development of theDreamachine by the artistBrion Gysin and technicianIan Sommerville, a device that has evolved into electronic devices known asmind machines.
Grey Walter's best-known work was his construction of some of the first electronicautonomous robots.[8] He wanted to prove that rich connections between a small number ofbrain cells could give rise to very complexbehaviors - essentially that the secret of how the brain worked lay in how it was wired up. His firstrobots, which he used to callMachina speculatrix[9] and namedElmer and Elsie, were constructed between 1948 and 1949 and were often described astortoises[10] 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 ofphototaxis, by which they could find their way to a recharging station when they ran low on battery power.
In one experiment, Walter 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."[11] 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 nameMachina docilis) and added to its simple single celled "brain" one, then two conditional reflex circuits in which they could be taught simple behaviors similar toIvan Pavlov's dogs.[citation needed] This tortoise was calledCORA. One of these included that 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, and this would make the animal become "afraid" wheneverfood was presented. Walter remedied this behaviour by severing the two additional circuits, and the tortoise reverted to being aMachina speculatrix. The conditioned reflex behaviour was later placed into a static desktop model, also known asCORA.
Later versions ofMachina speculatrix were exhibited at theFestival of Britain in 1951.[12]Walter stressed the importance of using purelyanalogue electronics tosimulate brain processes at a time when his contemporaries such asAlan Turing andJohn von Neumann were all turning towards a view of mental processes in terms ofdigitalcomputation. His work inspired subsequent generations of robotics researchers, includingRodney Brooks,Hans Moravec andMark Tilden.[citation needed] Modern incarnations of Walter'sturtles may be found in the form ofBEAM robotics.
In 2000, an original tortoise went on display in London, UK, in theScience Museum.[13] In 1995, this robot was also replicated by Dr.Owen Holland and Ian Horsfield[14] of theBristol Robotics Laboratory using some of the original parts.[15] An original tortoise as seen at theFestival of Britain is in the collection of theSmithsonian Institution.
Walter's papers including his letters, photographs and press cuttings form part of the Burden archive held at the Science Museum Library & Archives in WroughtonScience Museum at Wroughton.
Walter married twice. His first wife was Katherine Monica Ratcliffe (1911-2012), daughter ofSamuel Kerkham Ratcliffe (1868-1958), a former member of the executive of theFabian Society. They had two sonsNicolas Hardy Walter (1934–2000) and Jeremy Walter, who became a physicist.[1] After the couple separated in 1945, and divorced in 1946, their children were brought up by their mother Monica and her second husbandCambridge University scientistArnold Beck.
Walter's second wife was theradiographerVivian Dovey (1915-1980). They married in Bristol 1947[17] and had one child, Timothy Walter (1949-1976) before separating in 1960, and divorcing in 1973.[18] It has been noted that Walter and his institution gave a male biased view of their work. Vivian Dovey was a significant collaborator, yet she was depicted as a wife or assistant who cared for him.[16]
From 1960 to 1972, Walter lived with Lorraine Josephine Aldridge (née Donn), former wife of Keith Aldridge.[1] Vivian Dovey lived with Keith Aldridge and later took his name after her divorce.[18]
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