The hormone that may have triggered the financial crisis

Did you ever think - watching the way the bankers and share traders behaved in 2008 - that they were "on something"? Cortisol is a hormone. We all produce it at moments of stress. But too much of it for too long makes us dangerously risk averse at a time when we should be out there buying and investing. Dr John Coates of the Judge Business School at Cambridge University, talks about the dangers of cortisol in his new paper published in the Proceedings of the National Academy of Sciences. He speaks to the BBC's Roger Hearing.