Have you ever tried to look at a very faint light, a star or so? And did discover that you can see it better by looking next to it?
In a science edition of the NRC (Dutch newspaper) I read an article about unconcious thinking. In the article it was claimed that the concious mind is only suitable for simple decision, like buying toothpaste. But when it comes to really significant decisions, the complexity is too large for the concious mind. The unconcious mind is able to think much quicker and take much more complex thinking patterns than the concious mind. Decisions like buying a car or a house, changing your job or starting your own company are best left to the unconcious mind.
According to the experiment, a number of people were asked to listen to a large amount of unrelated information. Two groups were asked questions about the information after half an hour to verify what they remembered of it. One group was left to memorize the information and the other group conducted a numbering game that required them to use their rational abilities. It appeared that the second group was able to answer more questions correctly than the first group.
I was amazed by it, but it concurs with my own way of learning. If I absorb an amount of information and go do something else that takes my mind off the subject (playing on the piano or even studying a piece, for example), it is much easier to remember and see all kind of relationships in what I learned than when I try to stay concentrated and focussed. Sleep on it!