Cheerful people regroup faster and are still going strong on the 3rd/4th attempt to solve a problem. The higher-IQ person is more likely to get it right the fi

Cheerful people regroup faster and are still going strong on the 3rd/4th attempt to solve a problem. The higher-IQ person is more likely to get it right the first time. But there won't be much conviction on try No. 2, and after that, his/her position will be: "It doesn't work. Can't be done. Dumb idea." In a lot of work that I see, the IQ adjustment might be more like 10-15 points. For gnarly problems, we might still get better results with the really smart guy who's not 100% invested. And even grouchy geniuses can get enthused once they see that their ideas might work in a problem that has most other people stumped. Still, for problems that just require a lot of different attempts until something clicks, well-aimed enthusiasm can work wonders.