This is a podcast from the archives of the BBC Reith Lectures.

This lecture in the series The Emerging Mind, given by Villanour S. Ramachandran, was originally broadcast in 2003.

Good evening from the Nelson Mandela Lecture Theatre in Oxford, where an audience of scientists, artists and writers are waiting to hear the fourth wreath lecture on the subject of the human mind.

Our lecturer, a neuroscientist, is a man who's been a fan of Sherlock Holmes since he was a boy and in fact sees his work on the human brain as that of a detective in part,

presented with bizarre neurological cases, a man who believes his mother is an imposter,

a clinically blind man who can see.

He searches for the rational anatomical explanation.

So you can see that Freudian theories are being challenged here.

So far, we've learned that there are other

ways of seeing than through the eye. We've been shown ways of cheating the brain by using mirrors.

And last week, we were offered explanations as to why a Rodin sculpture or a Picasso sketch

can generate pleasure in our soul. Did I say so? Here we have a man who deals with more

tangible matter, the kilo and a half of jelly we call the brain. Tonight he confirms that people

who hear shapes or see sounds aren't mad or bad, but in fact provide us with clues to the

development of language and expression. Ladies and gentlemen, would you please welcome this scientific sleuth,

the Director of the Centre for Brain and Cognition at the University of California,

Professor Villanour Ramachandran.

In the 19th century, the Victorian scientist Francis Galton, who was a cousin of Charles Darwin,

noticed something very peculiar. He found that certain people in the normal population,

who were otherwise perfectly normal, had a certain peculiarity.

And that is, every time they heard a specific tone, they would experience a specific color.

For example, C-sharp might be red, F-sharp might be blue.

...