William Gray Walter

William Gray Walter (1949)

William Gray Walter (born February 19, 1910 in Kansas City , Missouri , † May 6, 1977 in Clifton, Bristol ) was a British neurophysiologist and robot researcher born in the United States .

Life

Walter was born in Kansas City, Missouri in 1910. His father, Karl Walter, was a British journalist who was working for the Kansas City star at the time. His mother, Minerva Lucrezia (Margaret) Hardy (1879-1953), was an American journalist of British origin. In 1915 the family moved to England and the son attended Westminster School (1922–1928) and then, until 1931, King's College, Cambridge . He then did postgraduate research , and his MA dissertation on electrical conduction in nerves and muscles was accepted in 1935. He then worked with the well-known neurologist FL Golla at London's Maudsley Hospital, who had a particular interest in the use of electroencephalography (EEG) in the clinical field and who commissioned Walter with the corresponding examinations on a wide variety of patients. In 1939 Golla and Walter went to Bristol and founded the Burden Neurological Institute, a soon internationally known research center for neuropsychiatry , where Walter worked until 1970. He did research work in the USA, the Soviet Union and various other places in Europe. Fluent in French, Italian, and German, he was a sought-after speaker and made frequent appearances on radio and television. He was married twice and had two sons from his first wife and a son from his second wife. During his life he was considered a pioneer in the field of cybernetics . In 1970 he suffered a serious traffic accident when he collided with a broken horse on his scooter - he had been driving a Vespa since 1947 -. He died seven years later on May 6, 1977 without fully recovering.

Act

Brain waves

As a young man, Walter was greatly influenced by the work of the well-known Russian physiologist Ivan Pavlov . He visited the laboratory of Hans Berger , who invented the electroencephalograph or electroencephalography (EEG). It was used to measure the electrical activity of the human brain. Walter developed Berger's machine further; with his version he discovered a number of different brainwave patterns. They ranged from the fast alpha waves to the slow delta waves he observed during sleep.

In his thirties Walter made a series of discoveries with his EEG machine at the Burden Neurological Institute in Bristol. He was the first to find the origin of the alpha waves correctly in the occipital lobe by measuring . He demonstrated how delta waves could be used to find brain tumors or wounds that were responsible for epilepsy. He developed the first brain topograph based on electroencephalography, for which he used cathode ray tubes arranged in a spiral and connected to highly sensitive amplifiers.

During World War II, he worked on scanning radar technology and remote-controlled missiles, which may have influenced his subsequent theory of the representation of brain activity by alpha waves.

Willful acts

In 1964 Walter and his working group in Bristol / England discovered the EKP component "Contingent Negative Variation" (CNV). This corresponds to a negative wave in a person's EEG between a first preparatory stimulus ("Attention!") And a second command stimulus ("Go!"), The time interval between the two stimuli varying at random. The CNV effect was understood as a sign that the brain was preparing for the next command, which was confirmed by a large number of other experiments.

The trigger for the discovery were abnormalities in EEG examinations on autistic children in 1962. In the period between two stimuli, a certain new type of EEG signal was noticed that Walter absolutely wanted to get to the bottom of. Diverse experiments during 1963 then led to reliable results, which were presented at two international EEG congresses in early 1964 and soon afterwards published in the journal Nature . The response in brain research has been enormous and lasting. By 1985 the work had already been cited more than 455 times.

These and subsequent results from others, in particular from Kornhuber and Deecke 1965 ( readiness potential ) and Libet 1983 ( Libet experiment ), led to a profound change ( paradigm shift ) in the understanding of voluntary actions in neuroscience . According to this, although their tendency is influenced by general planning decisions ( intentions , attitudes ), they are unconsciously initiated during the actual execution and only then are perceived as consciously controlled actions.

See also : Experiments on Free Will

robotics

Walter became known for the construction of one of the first autonomous robots. He wanted to prove that many connections between a small number of neurons can create complex behavior - in particular, finding the secret of how the brain works and how it's wired. He used to refer to his first robots as “Machina Speculatrix” and called them “Elmer” and “Elsie”. He built these robots between 1948 and 1949; they have often been described because of their appearance and their slow movements as "turtles" - and because they learn about the secrets of organization and life science taught . The three-wheeled tortoise-robots were capable of phototaxis ; they could find their way to a charging station when their batteries were dead.

In one of his experiments, he placed a light on the “nose” of a turtle and observed how the robot observes itself in a mirror. “It began to flicker,” he wrote, “trembling rapidly to and fro and bouncing like a heavy daffodil in the wind”. If this had been seen in an animal, Walter argued that it "might be accepted as an expression of a degree of self-awareness."

Later versions of the robots were exhibited at the Festival of Britain in 1951 . Walter emphasized the importance of fully analog electronics to simulate brain processes, while his contemporaries, such as Alan Turing and John von Neumann , saw their implementation of intelligent processes more in the areas of digital predictability. Walter inspired subsequent robotics researchers such as Rodney Brooks , Hans Moravec and Mark Tilden . Modern versions of Walter's "Turtles" can be found today in the form of BEAM robots.

In 1995 one of the original tortoises was recreated by Owen Holland at the University of West England - using some original parts. A second-generation turtle is on display at the Smithsonian .

Fonts (selection)

• The Living Brain . Duckworth, London 1953.
• An imitation of life . In: Scientific American . tape 182 , no. 5 , 1950, pp. 42-45 .
• A machine that learns . In: Scientific American . tape 185 , no. 2 , 1951, p. 60-63 .
• Contingent negative variation: An electrical sign of sensorimotor association and expectancy in the human brain . In: Nature . tape 203 , 1964, pp. 380-384 .

Web links

• Walter J. Freeman (University of California at Berkeley, USA): W. Gray Walter: Biographical Essay , in: Encyclopedia of Cognitive Science , 2003, Volume 4, pp. 537-539, ISBN 978-0-470-01619-0 . ( PDF )
• http://cyberneticzoo.com/tag/william-grey-walter/ Biographical documents and pictures

Individual evidence

1. ^ Ray Cooper: (William) Gray Walter (1910–1977) , in: Oxford Dictionary of National Biography , Oxford University Press 1985–1990, ISBN 978-0-19-861411-1 .
2. ^ Walter J. Freeman (University of California at Berkeley, USA): W. Gray Walter: Biographical Essay , in: Encyclopedia of Cognitive Science , 2003, Volume 4, pp. 537-539, ISBN 978-0-470-01619- 0 , PDF ( Memento from April 25, 2015 in the Internet Archive )
3. ^ WG Walter, R. Cooper, VJ Aldridge, WC McCallum, AL Winter: Contingent negative variation: An electrical sign of sensorimotor association and expectancy in the human brain. In: Nature. Volume 203, July 1964, ISSN  0028-0836 , pp. 380-384, PMID 14197376 .
4. ↑ Cornelis HM Brunia: CNV and SPN: Indices of anticipatory behavior , in: Marjan Jahanshahi, Mark Hallett (Ed.): The Readiness Potential: Movement-Related Cortical Potentials , Springer Science & Business Media 2003, pp. 207-227, ISBN 0 -306-47407-7 , p. 207.
5. ^ Ray Cooper: The discovery of the contingent negative variation (CNV) , In: Current Contents Life Sciences 21, May 27, 1985, PDF
6. ↑ Cornelis HM Brunia: CNV and SPN: Indices of anticipatory behavior , in: Marjan Jahanshahi, Mark Hallett (Ed.): The Readiness Potential: Movement-Related Cortical Potentials , Springer Science & Business Media 2003, pp. 207-227, ISBN 0 -306-47407-7 .
7. ↑ Steven P. Wise: Movement selection, preparation, and the decision to act: neurophysiological studies in nonhuman primates , in: Marjan Jahanshahi, Mark Hallett (eds.): The ready potential: Movement-Related Cortical Potentials , Springer Science & Business Media 2003 , Pp. 249-268, ISBN 0-306-47407-7 , pp. 260-262.