When you were a small child, did your parents tell you to go play outside already? Or were you the type that preferred to go outside to play anyway? In either case, going outside is not only good for you, but can even make you smarter, more creative, and happier? Wait, what?
It seems that there's some kinds of bacteria in most soils that can float through the air, and improves your brain's function should you inhale them. You're most likely to encounter them while walking on grass or dirt, and least likely inside, when you breathe mostly filtered air and have little contact with the soil. Mice given an aerosol spray of these bacteria could run a maze in half the usual time, and showed less anxiety to boot.
I'm also jokingly thinking about what these means to Internet addicts, who are stereotyped as shut ins. Could this be one of the reasons why they are so grumpy?