When you exercise your muscles, you don’t see immediate gains in strength. It’s only after you’ve rested that the strength gains occur. Neuronal connections seem to act similarly. When you’re thinking hard about a problem, it’s rare that you’ll have a eureka moment. The insight usually comes only after you’ve let the problem ruminate in your subconscious for a while. Stepping away from the problem and resting allows your brain to form new neuronal connections between thought centers that previously weren’t connected.
Letting a problem incubate helps you connect the seemingly unconnected.
People who study creativity often talk about the 3 B’s: The bed, the bath and the bus. Creative ideas seem to come to us when we’re not consciously thinking about them – after we’ve slept, while we’re doing mundane chores, while we’re daydreaming while we drive. A powerful example of this is set forth in this story from the NY Times: