This documentary looks at the fact that perhaps one in every hundred people experiences a blending of the senses. Imagine if every time you saw someone called Derek you got a strong taste of earwax in your mouth. It happens to James Wannertonwho runs a pub. Derek is one of his regulars. Another regular’s name gives him the taste of wet nappies. For some puzzling reason, James’s sense of sound and taste are intermingled. Dorothy Latham sees words as colours. Whenever she reads a black and white text, she sees each letter tinged in the shade of her own multicoloured alphabet, even though she knows the reality of the text is black and white. Spoken words have an even stranger effect. She sees them, spelled out letter by letter, on a colourful tickertape in front of her head. Both James and Dorothy have a mysterious condition called synaesthesia, in which their senses have become linked. For decades synaesthesia baffled the scientific community and noone could quite believe it was real. For a while hallucinogenic drugs were blamed, especially in the 1960s. Some put it down to an overactive imagination others thought it was caused by associations from childhood that had survived into later life. In the end noone could find out what was causing it, so synaesthesia was placed in the same scientific category as seances and spoon bending. But Professor Ramachandran thought it should be taken more seriously. He’s one of the world’s leading brain researcher. Having established a genetic link, scientists have now set out to discover what environmental influences might be shaping each person’s Synaesthesia. Clues to those environmental influences might come from the mind of James Wannerton and from his ability to taste words. Dr Jamie Ward is a neuro-psychologist who has been studying James for the past two years. He’s found that James consistently links the same words with the same tastes. Now he wants to discover if there’s a pattern to those links which may explain how they were first formed. Dr Ward has found that James’s synaesthetic tastes are from his childhood. There are no associations with foods from later in his life like olives or curry. What is remarkable is that John is able to see these colours at all, because for all his adult life he’s been blind. Neuroscientists have discovered that our different senses seem to be processed in separate areas of our brains, so the vision areas are usually only triggered by signals from the eye, the hearing areas only by signals from the ears and it’s the same with other senses like touch. Not only is the sound area of the brain active, but parts of the visual area have been triggered as well. Areas, which should only be activated by a signal from the eye. So Synaesthesia is caused by the creation of special working connections between areas of the brain which are normally quite separate. Synaesthesia could be a manifestation of how we have learned to work with abstract concepts, to manipulate numbers and ideas. Something that has defined our species and helped shape our civilisation and some scientists go even further. Scientists think synaesthesia may help explain another critical skill that defines us as human, our creativity. This idea was developed when one scientist began to wonder about the genetics of synaesthesia. What purpose did these genes actually serve? Today, synaesthesia is no longer regarded simply as a bizarre or rare condition. It may now be opening a window into our greatest mysteries and some of our greatest achievements.