If you want to get to know someone, a biography is more useful than a brain scan. Indeed, a biography is the attempt to understand someone as fully as possible, not just to trace out what they have done, but also to try to understand how they see the world and why. Imagine you are asked to write a biography of someone you don't know. How would you set about your research? In all probability you'd want to know where the person was born, into what family. You'd trace significant influences, people, places, events that impinged on your subject's life. The significance of each of these for your subject will vary. Some major events – a world war, for example – may actually affect your subject only peripherally; others, like the loss of a parent, will be profound. You gradually build up a picture of what your subject has done with his or her life, and of all the relationships and influences that have impinged on him or her along the way. In doing this, you are trying to get a rounded image of the person as they are now; you are trying to get under their skin. And you rightly assume that to do this you do not need to carry out an operation on their brain or to await a full analysis of neural activity. What you need to do, in order to understand how and why they are as they are, is to understand their history, but to do so in a particularly sensitive and empathetic way.