Hugh Christopher Longuet-Higgins was born 11 April 1923, the second of three children born to Rev. Henry Hugh Longuet-Higgins and Albina Cecil Longuet-Higgins in Lenham, Kent. He joined the Pilgrim’s School, Winchester, in 1932, and became a senior chorister at the cathedral. Three years later he won a scholarship to Winchester College, having exhibited great abilities in math and music.

In 1941, he won a scholarship to Balliol College, Oxford, to read chemistry, but at the end of his first year took part one of the music tripos and was appointed Balliol College organ scholar.

As an undergraduate at Oxford, he proposed the correct structure of the chemical compound diborane. He completed his doctorate at Oxford and conducted postdoctoral work at the University of Chicago and the University of Manchester. From 1952 to 1954, he was professor of theoretical physics at Kings College, London. In 1954, Longuet-Higgins became professor of theoretical physics at Cambridge and a fellow of Corpus Christi College.

A growing interest in the brain and the new field of artificial intelligence led him to the University of Edinburgh, where, in 1967, he co-founded the department of machine intelligence and perception. The department encouraged collaboration in an interdisciplinary research group including computer scientists, linguists, psychologists and neuroscientists. It was Longuet-Higgins who, in 1973, was the first to name the field ‘cognitive science’.

In 1974, he moved to the experimental psychology department of Sussex University, where he made major contributions in the areas of vision, language production and music perception. He retired in 1984. An accomplished pianist, conductor and composer, after retirement he returned to the problem of how to generate automatically from a score a performance that would sound musical.

Professor Longuet-Higgins was a Fellow of the Royal Society and the Royal Society of Arts. He is the only person to be elected a Fellow of the Royal Society twice in two different disciplines—chemistry and artificial intelligence. He was a foreign associate of the U.S. National Academy of Sciences and served as a governor of the BBC from 1979 to 1984. He was a Fellow of the International Academy of Quantum Molecular Science.

He held honorary doctorates from the universities of York, Essex, Bristol, Sussex and Sheffield. The honorary doctorate from Sheffield was in music.

Christopher Longuet-Higgins died 27 March 2004.