William Grey Walter

William Grey Walter (19 February 1910 – 6 May 1977) was an American-born British neurophysiologist, cybernetician and robotician.

Early life and education Walter was born in Kansas 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 the Kansas City Star 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 to England in 1915, educated at Westminster School with an interest in classics and science, and entered King'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). 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, 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, 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 a brain injury in a motor scooter accident. He never fully recovered and died seven years later, on 6 May 1977.

Brain waves As a young man, Walter was greatly influenced by the work of the Russian physiologist Ivan Pavlov. He visited the lab of Hans Berger, who invented the electroencephalograph, or EEG 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 of brain wave types ranging from the high speed alpha waves to the slow delta waves observed during sleep. In the 1930s, Walter made a number of discoveries using his EEG machines at the Burden Neurological Institute in Bristol. He was the first to determine by triangulation the surface location of the strongest alpha waves within the occipital lobe (alpha waves originate from the thalamus deep within the brain). Walter demonstrated the use of delta waves to locate brain tumours or lesions responsible for epilepsy. He developed the first brain topography machine based on EEG, using an array of spiral-scan CRTs connected to high-gain amplifiers. During the Second World War, Walter worked on scanning radar technology and guided missiles, which may have influenced his subsequent alpha wave scanning hypothesis of brain activity. In the 1960s, Walter also went on to discover the contingent negative variation (CNV) effect whereby a negative spike of electrical activity appears in the brain half a second prior to a person being consciously aware of movements they were about to make. Intriguingly, this effect brings into question the very notion of consciousness or free will, and should be considered as part of a person's overall reaction time to events. Walter's experiments with stroboscopic light, described in The Living Brain, inspired the development of the Dreamachine by the artist Brion Gysin and technician Ian Sommerville, a device that has evolved into electronic devices known as mind machines.

Robots

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