Do you want to improve your ability to concentrate? Take a walk!
But wait! Don't just walk anywhere.
In the paper "The Cognitive Benefits of Interacting With Nature" (Berman, et. al, 2008), published in Psychological Science, the authors discuss how a walk through a natural setting can refresh your brain. A walk in the city seldom does; it requires too much directed attention. Car horns force you to focus on not getting run over. You have to consciously ignore billboards, ringing cell phones, and other mentally jarring intrusions just to get some peace. Natural settings, on the other hand, give your brain some much needed breathing room. You might see and hear interesting things, but they aren't urgently forcing your brain to pay attention.
(Mama Joules' digresses: OK, so I have to wonder about this. What if your natural setting isn't so peaceful? Maybe you are hiking through an untamed forest complete with stinging insects, the threat of extreme weather, and the potential for attacks by large hungry wildlife? Would you still feel refreshed and restored afterward?!)
The authors conducted a study among college students and sent them for walks under different conditions. The students were able to concentrate better on a memory test after a walk along a wooded path (as opposed to the densely populated city street). This effect held true even if the participants were in a bad mood or the weather was foul.
So, the next time that you or your child are stuck on a hard problem -- be it homework, a tax question, or how to seat your relatives at the dinner table so that they won't fight over the rolls -- take a time out and go for a walk in the park.
(But take my advice: If you're seeking solace and mental restoration, go for a relatively tame natural setting. No bears!)