Well, we knew already that people who are depressed and those who didn't believe in their ability to remember tend to perform more poorly on tests of memory and cognition. Now an imaging study has found that the brains of seniors with low self-worth were up to a fifth smaller than those who felt good about themselves. Learning to think positively is therefore likely to have cognitive benefits as well as emotional ones.

And although this is somewhat off-topic, I couldn't resist this one: according to new imaging research presented at the Neuroscience conference, money is more rewarding when it is earned. Moreover, the sense of accomplishment in achieving your task appears more rewarding than the money itself. (BioMedNet report - free registration required)