H. Christopher Longuet-Higgins

Hugh Christopher Longuet-Higgins FRS FRSA FRSE (April 11, 1923 – March 27, 2004) was both a theoretical chemist and a cognitive scientist.

Longuet-Higgins was born on 11 April 1923 in Lenham, Kent, England.His father was Henry H. L. Longuet-Higgins and his mother was Albinia Cecil Bazeley.He was educated at The Pilgrims' School, Winchester, and Winchester College. In 1941, he won a scholarship to Balliol College, Oxford. He read chemistry, but also took Part I of a degree in Music. He was a Balliol organ scholar. As an undergraduate he proposed the correct structure of the chemical compound diborane (B₂H₆), which was then unknown because it turned out to be different from structures in contemporary chemical valence theory. This was published with his tutor, R. P. Bell. He completed a Doctor of Philosophy degree in 1947 at the University of Oxford under the supervision of Charles Coulson.

After his PhD, he did postdoctoral research at the University of Chicago and the University of Manchester. In 1952, he was appointed Professor of Theoretical Physics at King's College London, and in 1954 was appointed John Humphrey Plummer Professor of Theoretical Chemistry at the University of Cambridge, and a Fellow of Corpus Christi College, Cambridge. While at Cambridge he made many original contributions in the field of Theoretical Chemistry. Among the most important were his introduction of the occurrence of Geometric phase at the conical intersection of potential energy surfaces, his introduction of the correlation diagram approach to the study of Woodward-Hoffmann rules, and his introduction of nuclear permutation-inversion symmetry groups for the study of molecular symmetry. In his later years at Cambridge he became interested in the brain and the new field of artificial intelligence. As a consequence, in 1967, he made a major change in his career by moving to the University of Edinburgh to co-found the Department of Machine intelligence and perception, with Richard Gregory and Donald Michie.

In 1974 he moved to the Centre for Research on Perception and Cognition (in the Department of Experimental Psychology) at Sussex University, Brighton, England.In 1981 he introduced the essential matrix to the computer vision community in a paper which also included the eight-point algorithm for the estimation of this matrix.He retired in 1988. At the time of his death, in 2004, he was Professor Emeritus at the University of Sussex. His work on developing computational models of music understanding was recognized in the nineties by the award of an Honorary Doctorate of Music by the University of Sheffield.

An example of Longuet-Higgins's writings, introducing the field of music cognition:

Longuet-Higgins (1979): —

You're browsing, let us imagine, in a music shop, and come across a box of faded pianola rolls. One of them bears an illegible title, and you unroll the first foot or two, to see if you can recognize the work from the pattern of holes in the paper. Are there four beats in the bar, or only three? Does the piece begin on the tonic, or some other note? Eventually you decide that the only way of finding out is to buy the roll, take it home, and play it on the pianola. Within seconds your ears have told you what your eyes were quite unable to make out—that you are now the proud possessor of a piano arrangement of "Colonel Bogey".

Honours and awards

Christopher Longuet-Higgins was elected a Fellow of the Royal Society in 1958, a Foreign Associate of the US Academy of Sciences in 1968 a Fellow of the Royal Society of Edinburgh (FRSE) in 1969, and a Fellow of the Royal Society of Arts (FRSA) in 1970. He was a Fellow of the International Academy of Quantum Molecular Science. He had honorary doctorates from the universities of Bristol, Essex, Sheffield, Sussex and York. Among his notable prizes were the Jasper Ridley prize in music from Balliol College, Oxford, the Harrison memorial prize from the Chemical Society, and the Naylor prize from the London Mathematical Society. He was a governor of the BBC from 1979 to 1984.

In 2005 the Longuet-Higgins Prize for "Fundamental Contributions in Computer Vision that Have Withstood the Test of Time" was created in his honor.The prize is awarded every year at the IEEE Computer Vision and Pattern Recognition Conference for up to two distinguished papers published at that same conference ten years earlier.

His younger brother is Michael S. Longuet-Higgins. Longuet-Higgins died on 27 March 2004, aged 80. Although he respected many of the features of the Church of England, he was an atheist.

• Geometric phase
• Diborane
• William Lipscomb
• Woodward-Hoffmann rules
• Molecular Symmetry