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A book and an exhibition: Illusion in Nature and Art


Classifying illusions and representing the three-dimensional in art
Richard Gregory Scientist
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Well, I’ve been trying to classify them. Actually, that’s what I do in my old age, I’ve been trying to look at all the illusions I can find or discover or know about, and then I put them into classes and I think in biology it’s immensely important, you think of evolution and classifying species, I mean chemistry and all of that, periodic table, incredibly important for revealing the ultimately structure of atoms. Now, I think the same is true with illusions. I think classifying them is really important but to classify them you have to relate the things to some sort of theory to get the criterion for the classes so that the classification is not empty, it actually relates to the theory and can modify the theory. If a theory predicts that one phenomenon should be different from another or in some way similar, you know, in order words is will modify the classification, that’s the power of the theory but then the power of the classification is it can modify the theory and, of course, when you’ve got a classification and you’ve got a gap, you’ve got something missing, then you might say, oh, golly, there’s got to be something in that gap for the whole story to work, that then suggests either you look for more data or you look at the theory again. And so that interplay between phenomena and classifying them and then the theory, I think is what science is all about and I’m trying to do that with illusions. What about illusions in art? Well, art, of course, is amazingly interesting because you’re representing the world of three dimensional, solid objects with pigments which effectively are not solid on a flat screen and how do you compress the world of three dimensions into a flat screen? This, of course, is something that Leonardo thought about, I mean it goes back certainly 400 years in the history of art and I’m very, very interested in that. How the brain works when you cut the information from three to two dimensions but you’re representing three dimensions. What happens is you get ambiguity. In other words, you get many possibilities from the same pattern as to what the object might be and ambiguity is an important class of illusions. Now, what is interesting is that ambiguities can be dynamic. The brain will guess one thing, change its mind, and say, no, no, it’s not that, it’s another, and it’ll flip from one possibility to another spontaneously and you see the thing flipping. Turner actually used this sort of thing in a very subtle way in his paintings, which gave his paintings life. As you go on looking at them, there are subtle changes in the sky, in the clouds, because of this ambiguity generated by the observer but given by Turner’s painting which is deliberately vague and misty, indeterminate, so that the viewer’s brain can take off, be creative, and entertain various possibilities. That’s why Turner is such an amazing painter; he controlled the viewer’s brain, allowing it freedom to entertain alternative possibilities.

The late British psychologist and Emeritus Professor of Neuropsychology at the University of Bristol, Richard Gregory (1923-2010), is well known for his work on perception, the psychology of seeing and his love of puns. In 1978 he founded The Exploratory, an applied science centre in Bristol – the first of its kind in the UK. He also designed and directed the Special Senses Laboratory at Cambridge which worked on the perceptual problems of astronauts, and published many books including 'The Oxford Companion to the Mind', 'Eye and Brain' and 'Mind in Science'.

Listeners: Sally Duensing Adam Hart-Davis

Sally Duensing currently is involved in perception exhibition work and research on science and society dialogue programmes and is working with informal learning research graduate students and post-docs at King's College, London. In 2000 she held the Collier Chair, a one-year invited professorship in the Public Understanding of Science at the University of Bristol, England. Prior to this, for over 20 years she was at the Exploratorium, a highly interactive museum of science, art and perception in San Francisco where she directed a variety of exhibition projects primarily in fields of perception and cognition including a large exhibition on biological, cognitive and cultural aspects of human memory.

Born on 4 July 1943, Adam Hart-Davis is a freelance photographer, writer, and broadcaster. He has won various awards for both television and radio. Before presenting, Adam spent 5 years in publishing and 17 years at Yorkshire Television, as researcher and then producer of such series as Scientific Eye and Arthur C Clarke's World of Strange Powers. He has read several books, and written about 25. His latest books are Why does a ball bounce?, Taking the piss, Just another day, and The cosmos: a beginner's guide. He has written numerous newspaper and magazine articles. He is a keen supporter of the charities WaterAid, Practical Action, Sustrans, and the Joliba Trust. A Companion of the Institution of Lighting Engineers, an Honorary Member of the British Toilet Association, an Honorary Fellow of the Royal Photographic Society, the Royal Society of Chemistry, the Society of Dyers and Colourists, and Merton College Oxford, and patron of a dozen charitable organizations, Adam has collected thirteen honorary doctorates, The Horace Hockley Award from the Institute of Scientific and Technical Communicators, a Medal from the Royal Academy of Engineering, the Sir Henry Royce Memorial Medal from the Institute of Incorporated Engineers, and the 1999 Gerald Frewer memorial trophy of the Council of Engineering Designers. He has no car, but three cycles, which he rides slowly but with enthusiasm.

Duration: 3 minutes, 14 seconds

Date story recorded: June 2006

Date story went live: 02 October 2009