In Jonah Lehrer’s article about the benefits of depression, nothing seemed solid until I came across this:
[Joe] Forgas [an Australian psychology professor] 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 [vary] mood, Forgas conducted the survey on gray, rainy days â€” he accentuated the weather by playing Verdiâ€™s â€œRequiemâ€ â€” and on sunny days, using a soundtrack of Gilbert and Sullivan. The results were clear: shoppers in the â€œlow moodâ€ 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.
I found the scientific article that reports this experiment, in Journal of Experimental Social Psychology. Memory for the trinkets was measured two ways — recall and recognition — and both ways the “sad” shoppers did much better. I didn’t know about this; the size of the effect suggests it’s important. Calling it variation in “memory” is odd, since the remembered event was only a minute ago. Variation in attentiveness is a better summary.
Whatever you call it, I like the general point made in the scientific article. When you are in a good mood, you pay less attention to your surroundings than when you are in a bad mood. When you’re in a good mood, the model of the world in your head is working well. No need to change it. When you’re in a bad mood, the model of the world in your head isn’t working well. Time to gather more data and revise it.
My colleagues and I have studied a different effect along these lines (in rats): When things aren’t going well, you vary your actions more. You try new things more. That’s another way to update your model of the world.