Interesting observation. It is hard to find an in-depth article in Google Scholar on the idea that meditation or similar practices evolved to help us deal with stress and hone concentration. A recent study showed that nuns and monks who prayed or meditate showed increased activity in the parts of the brain implicated in analytical thinking and stress management.

My question is are these simply tricks we learned to deal with stress, or were they are part of human evolution to help cope with stress?

http://intro2psych.wordpress.com/2008/03/11/and-this-is-your-brain-on-prayers/