Professor Richard Gregory: Scholar with a mind for science and art

His research ranged from the detailed examination of the eye of a marine crustacean to matters of human consciousness after observing his wife's unpredictable behaviour at a restaurant.

Professor Richard Gregory was famous for his science TV show.

Through his work on visual perception, Professor Richard Gregory made a considerable impact both in the fields of arts and science and humanities. His research ranged from the detailed examination of the minute eye of a marine crustacean to the conclusions he drew on the matter of human consciousness after observing his wife's unpredictable behaviour at a restaurant one evening. Born in London in 1923, Gregory attended the University of Cambridge and studied experimental psychology through philosophy before undertaking research at the Medical Research Council's Applied Psychology Unit in the same city. During the war he served in signals in the Royal Air Force, and in 1946 was assigned the task of explaining radar and communication systems to members of the general public who passed by the bombed site of the department store John Lewis in Oxford Street. It was a highly successful enterprise designed to encourage a wider understanding of science and technology, and during a period of six months he addressed four million visitors in all.

At the Psychology Unit he served first as a demonstrator, later a lecturer, remaining at Cambridge until 1967. Commissioned by Nasa to research sensory perception problems that astronauts in the first moon landing might encounter, he devised a practical experiment. Along the side of one of the unit's laboratories he constructed an electric railway. On the walls he placed visual displays that changed in size counter-intuitively as the viewer passed by, shrinking as he approached and expanding as he withdrew. The set-up simulated the disorienting conditions the astronauts could expect to experience in space. Various other inventions followed, including a chromatic photometer, a solid-image microscope and a three-dimensional drawing machine.

The case that set Gregory on his lifelong course of study concerned a man who had been blind from birth, only to have his sight restored at 52 following successful corneal implant surgery. Gregory was fascinated to discover that the man, known as SB, found tactile experiences confusing. He could not judge distances and was fearful of traffic. In time, he was transformed by the gift of sight from a self-confident and sociable man to a loner who preferred to sit in the dark at home rather than engage with the new, all too vivid and complex world to which he had suddenly been granted access.

Studying the development of SB's perception changed the way Gregory came to think of visual perception and its close relationship to touch. From the 1960s onwards, his research focused on the idea that sensory information provides only ambiguous evidence for what we see, or believe we see. In many aspects, his studies were a continuation of the ideas put forward by his scientific hero, the 19th-century German physicist and physiologist Hermann von Helmholtz, who proposed the notion of "unconscious interference". For von Helmholtz, perception involved implicit knowledge, experience and expectations about the world, not merely the act of observing something with the naked eye.

In 1966, Gregory published the first of a number of popular books, Eye and Brain, in which he expounded his theories on the psychology of seeing. He was also fascinated by optical illusions and artificial intelligence, and his knowledge on the complexities of the human visual system attracted the attention of Roman Polanski, who wanted to work with Gregory on a 3-D horror film. In 1970 the two men had a series of meetings, riding around London in the back of Polanski's white Rolls Royce, discussing aspects of a film that, ultimately, was not made. Passionate about interesting young people in science, he gave the Royal Institution's Christmas lectures for children in 1967, and later established the Exploratory (now Explore@Bristol), a hands-on science centre in Bristol and the first of its kind in the UK. He was also behind the "Launch-Pad" permanent exhibit at London's Science Museum.

He is survived by two previous wives, two children and his longtime companion, Priscilla Heard. Richard Langton Gregory. Born July 24, 1923; died May 17, 2010. * The National