Jonathan Miller talks to eminent psychologists - 12 people who contribute in very different ways to our understanding of the human mind.
Until the 20th century vision was often regarded as a simple process - the eyes provide the brain with pictures of the outside world, and the brain just looks at them. It is now known that visual perception is one of the most complicated functions the human brain performs. Professor Richard Gregory from the University of Bristol shows how the study of illusions has demonstrated how, much of what one sees 'out there' is actually generated from within. Production PHILIP SPEIGHT David f. TURNBULL (R)