Cognitive Daily (link via scoble) reports on an intriguing study on the relationships between mood and being able to synthesize memories - basically, if you're in a great mood, it looks as though you are more able to make what psychologists call 'gist' memories - an artificial memory that's based on deduction.
It always fascinated me how human brains can do this. At some point in time, some hairy ancestor of yours and mine figured out that five seeds lying in the cave were the same as five fruits - that the concept of 'five' was common. And then went on to apply the newly 'remembered' concept of 'counting things' to all sorts of stuff.
(This leap of faith is brilliantly illustrated in Robert L Forward's Dragon's Egg - one of my all time favorite books - which you should really read if you get a chance).
So it turns out that being happy means that you're more likely to make such a leap -that you're actually smarter when you're happier. That's not too surprising - I spent this week in a fairly glum mood, and I felt that my work probably suffered a bit because of it. I'm sure everyone has had similar experiences.
It all adds more weight to something that I've always believed - that anyone responsible for managing people should do their very best to ensure that they are happy. Unhappy people don't produce great things, in fact, come to think of it, they end up sabotaging things. Optimizing the mood of your team is absolutely critical to any projects success.