Genius Radio documentary.

Modern brain scanners can see the mind at work. They can also raise moral issues. More "Mysteries of the Brain" this week on The Changing World

First Half
The mechanics of making a simple decision(such as deciding to move our arm to pick up a glass of water) may be more complex than we might assume. Barry Smith, director of the Institute of Philosophy at the University of London's School of Advanced Study, looks at the brain's role in routine as well as sophisticated decision making.

Second Half
It's a fair assumption that when several people look at the same thing; they see the same thing. You see a smiling face, I see a smiling face. But that's not always the case. Philosophy professor Barry Smith ventures into our consciousness; how we perceive stimuli; and how technology is being used to read our minds.