It is no wonder that bank capital is regulated. When borrowing and lending is profitable, it is tempting for banks to scale up their operations and to borrow and lend too much in relation to their capital, in effect reducing the effectiveness of the potential capital cushion.

Personally, I don't see old economics and behavioural economics as opposed. It is useful to assume people are rational as a good approximation to their long term behaviour, but it would be unwise not to think how in practice their behaviour may deviate from that simplifying assumption.

For years, we've grown dependant on American consumers as the world's spenders of last resort. They've kept Europe out of recession, allowed China to industrialise, and prevented global deflation. But at the same time, they've not been looking after their own futures.

Interestingly, human irrationality is a hot topic in economics at the moment. Behavioural economics it's called, on the cusp of economics and psychology.

Even though disciplined sleeping habits and the adrenalin of live radio ensures that we are very awake while on duty, there is evidence of a phenomenon called circadian desynchronosis which causes one's brain to function slowly at those times of day when it thinks it should be asleep, regardless how wide awake the body is.

I've never enjoyed sleep as much until I got the 'Today' job. There is something about early sleep that's much better than late sleep. I feel myself going to sleep; I don't just plonk my head on the pillow. It's a sort of winding-down thing.

It is no wonder that bank capital is regulated. When borrowing and lending is profitable, it is tempting for banks to scale up their operations and to borrow and lend too much in relation to their capital, in effect reducing the effectiveness of the potential capital cushion.