Last year, Forgas ventured beyond the lab and began conducting studies in a small stationery store in suburban Sydney, Australia. Forgas placed a variety of trinkets, like toy soldiers, plastic animals and miniature cars, near the checkout counter. As shoppers exited, Forgas tested their memory, asking them to list as many of the items as possible. To control for the effect of mood, Forgas conducted the survey on gray, rainy days — he accentuated the weather by playing Verdi’s “Requiem” — and on sunny days, using a soundtrack of Gilbert and Sullivan. The results were clear: shoppers in the “low mood” condition remembered nearly four times as many of the trinkets. The wet weather made them sad, and their sadness made them more aware and attentive.

There are two important lessons of this research. The first is that our fleeting feelings can change the way we think. While sadness makes us more focused and diligent – the spotlight of attention is sharpened – happiness seems to have the opposite effect, so that good moods make us 20 percent more likely to have a moment of insight. The second takeaway is that many of our creative challenges involve tasks that require diligence, persistence and focus. It’s not easy making a collage or writing a poem or solving a hard technical problem, which is why sometimes being a little miserable can improve our creative performance.