What's in a face?

Faces are the most important biological stimuli we see and we've evolved to be exquisitely sensitive to the most minute changes in another person's face. But what happens when our brain's ability to recognise the human face breaks down? In All in the Mind this week, some intriguing research on how our brains process faces, and we hear one inspiring woman's story of what it feels like not to even recognise her family and friends, and what strategies she uses to adapt to her condition of 'face blindness'.