White Noise
I have been experimenting with white noise lately, more so, to ward off external noises, rather than to validate the claim that such noises improve the cognitive skills. I admit, I like quiet workplaces. And I know, it's a luxury not everyone can have. It might have to do with luck as well -- if you get the hint. :)
Anyway, case in point being, white noises do help me in two ways: A. of course, as expected, they block external (non-uniform) noises; and B. I don't have to worry about -- as in the case of music -- managing the playlist and all.
"Improving the cognitive skills"...erm...I don't know! :) Maybe...maybe not.. little do I care! There are various YouTube videos, Websites, SoundStreams that offer rain sounds, cafe sounds, etc. The one I use the most is called RainyCafe. I stick to the 'rain' mostly, but every once in a while I've tried out their 'cafe' option as well.
Do try out a 'white noise' next time you're trying to concentrate on something, and need to disconnect. It helps.