Our
brains have remarkable filtering capabilites. Everyday, we throw away huge amounts of
information because we deem them irrelevant.
For example, when I was a child, I was facinated by everyday objects in the bathroom or the kitchen. I simply had to know what purpose every surface, handle, dial or switch held. Now, I can walk into one of those rooms and not give it a second thought.
However, the process of seperating relevant information from useless information is a boon to creativity. Take a guitar player playing a solo. With 6 strings across 24 frets, he has to choose 1 through 6 notes out of a possible 144 notes. But, due to knowledge, or even intuition, he can choose only from the notes that will sound pleasing to the ear.
A chess player might have over 30 possible moves. When looking moves ahead, the number of possible board configurations grows exponentially. For each of his 30 possible moves, his opponent might have 30 replies.. Then, for each of those, he could have another 20 or 30 replies. Luckily, the brain can discard the moves that would not be very beneficial. (Although, it can discard beneficial moves..)
When stuck in a rut, I have gone through days where my brain has deemed almost everything irrelevant.